How does everyone stabilize Idle Torque and/or Timing at Idle?

I have been through over 100 logs trying to get VVE and MAF correlated to what my wideband tells me, although I doubt my wideband sometimes. I thought the issue was I just didn't have VVE good enough and after messing with VVE and MAF this long its starting to make me think otherwise. No other idle settings seems to change a thing (torque reserve, PI control gains, VTT at idle region, etc.).

Once the immediate torque control source goes to idle the timing starts jumping up and down almost going negative and then going back to almost 30 degrees, which causes really annoying bucking at idle and its especially annoying at rolling idle with the foot on the brake.

You can see it here right when I put my foot on the gas the the immediate engine torque command source switches to axel from idle timing stabilizes:
Attachment 97342

To me all the other torque PIDs look normal. Zero pedal engine torque, immediate engine torque commanded, and delivered engine torque all say around the same value, my scanner shows I am sampling them all at the fastest rate although it looks to me like some of them aren't actually sampling that fast, so I may be aliasing some of the data since timing and rpm are jumping around faster than some of my torque PIDs seem to be updating. I am also running open loop since I have my wideband in place of my bank 2 O2 sensor.

I still am trying to make sense of the confusing mess of torque PIDs, but it appears to me that the torque PID's agree, but its almost like the torque command is what's fluctuating and making the timing fly around trying to match it, I'm getting almost a 100 rpm swing at idle. I know I should bump my idle up but the issue does not completely go away until about 1000rpm idle.

On a sidenote I just noticed my VVE table at the powerband region 5000-6000rpms is barely over or equal to the stock VVE table and I've adjusted it from wideband feedback, the lower rpms are 20-30% less, this just dosent make sense to me, but I had to take a lot out at low rpms and idle regions from stock though.

Attachment 97345

Attachment 97346

So I wanted to bring this back up. I think maybe this negative timing at idle has caused my cats to start failing, or it could just be from the overlap and extra unburnt fuel.

I have tried all kinds of combinations of adjustments with the proportional and integral gain (which I am not entirely convinced it is a gain and also given it has units assigned to it (ft-lbs), I am thinking it could be a error value difference). I have tried all kinds of different settings for the external load and limit offset as well, which I don't believe should be adjusted from stock since the HP Tuners description says this table "models the engine load" which makes sense as it is based on oil temp which should make a big difference in how much torque is needed to turn the engine over.

After messing with all the stuff trying to make sense of it and experimenting, I have basically concluded not much of anything besides if you deviate them too far from stock it will kill the engine. No matter what combination of values I try nothing will make the timing go higher, so the ECM is always trying to reduce delivered torque. The predicted control however will respond consistently no matter the gain values, so as the immediate control command pulls the timing back (sometimes to -20 degrees), the predicted will respond and open the throttle blade (sometimes to 20% or so).

I am not a big fan of having to change the virtual torque tables that much from stock. Since I believe GM tuned in particular the airmass table to be accurate. So if I haven't fundamentally altered the combustion chamber design or significantly reduced friction losses then the porting and cam I have done will then just pull more airflow and then the PCM will reference higher airflow torque values in the tables. That being said I understand sometimes we can't do everything exactly right given we don't have full access and control and we will have to do work around. For example, I think it is necessary that I update the MAP based torque table since the engine could theoretically make more torque with the same MAP value from stock. Also it may be necessary to slightly bump the VT tables globally since I have increased compression. Is that logical thinking?

So it appears that the trend is when I decrease VT in the idle range, I get extremely low idle timing until it eventually dies.

When I increase VT I get extreme instablity in idle timing where it bounces from very high to very low values, so somewhere there is maybe some kind of discontinuity in the table references causing oscillation at idle.

As always I really appreciate the help everyone puts in to help other with tuning as this stuff can become so frustrating. I really hope there is someone out there who has figured out GEN V torque based tuning with cams. I don't expect a stock like idle with a large cam, but it seems like I should at least be able to get timing under control.

So I realize the importance when you are tuning these GEN V controllers that VVE must be dead on since everything is referenced from the VVE airflow model. However, I have spent hours and hours logging correcting and reflashing to try to get VVE better.

That being said I have tried a few other things. I rescaled the y-axis on the leading edge angle table for the high pressure fuel pump in effect to model the "32% increase" fuel lobe I have from my cam swap. I was really thinking this might be my issue but so far doesn't seem to have made any difference in anything, I didn't really have any large fluctuations in commanded versus desired high fuel pressure anyway. I also figured, especially since so much timing is being pulled and effecting combustion and combustion stability, that I would cut fuel pressure at idle. This did end up increasing pulse width a couple ms, but unfortunately didn't seem to do anything either.

Its stressed so much and for good reason that VVE has to be dead on or you will be going around in circles, so I am pretty confident this has got to be my problem. The thing is I have spent months and months and log after log, logging histograms of wideband error and fuel trims in every which way I can think of and feeding that back into VVE and trying to correct. I just am going in circles as well, the error is not converging, I have tried many ways of filtering as well. I think the negative timing along with the high overlap in the cam bring in exhaust charge to dilute the intake is causing false feedback with the wideband.

This wouldn't be so much of a problem if I could manually use the bi directional controls to force spark and throttle to where I need it to be but none of this is working since I have heard if your air models are off the commands won't work. However, I have found sort of a alternate method, I use the bi directional controls to lock the highest gear I can and force the TCC solenoid on. Then I go drive up and back up a hill so I can basically hold the engine at idle speed (500-600 rpms) but the torque source is axle not idle since I am moving the car at around 10mph. I feel like if I keep doing this though I am going to ruin crank bearings or the TCC clutch or something but hopefully not. I have done this countless amounts of time, but even with this my error is not converging, I wouldn't say its diverging either.

I also have noticed it is having the same low timing problems at very very light throttle as well. I can watch it in the scanner and see that "axle" is my commanded torque source and see timing at 0-10 degrees and accelerator foot pedal position at around .5-4% I will be creeping along slowly up high at about 1 or 2 percent throttle and all the sudden timing will go to its normal 30 degrees of timing then all of the sudden drop back to 0 or 10 and you can feel the car stumble back and forth. Its really bad when you creep along with the TC locked in high gear and I go to lighter throttle where it starts doing the low timing stuff and it rattles the entire drivetrain and pinion gears back and forth and feels like the car is about to come apart.

I just don't get it, how is everyone else doing it? I have heard that under +/-5% is the target, I just don't see how anyone is getting there given the instability of O2 feedback, inability to control timing, and error in back solving VVE coefficients.

For some reason I can't get my log file to upload so here is a link to download:
https://1drv.ms/u/s!AkCUE89IhD0Ng-B1...Z8eKA?e=IOtUdN

When you change the cam you change the air model which changes the torque output. Especially at idle. Torque is greatly reduced at idle with a larger cam. The vtt needs to be changed to reflect this. It takes a lot of time getting this right as it's more of trial and error. Start by unchecking the link selections box and make changes to each table individually. I'll start with reducing the torque by 20% in the rpm, airmass, and map in the idle areas of the -10 and 0 degree tables. Then 15% in the 10 degree, 10% in the 20 degree and 5% in the 30 degree. Larger cams I'll reduce 30% in the lower timing tables and gradient up from there. You also need to smooth the tables out from the idle cells up in rpm, airmass, and map so you don't just have a big chunk of torque removed from the idle areas and stock the rest of the table. Changes also need to be made all at once before you hit the calculate button. And once you calculate that's it. If you need to make further changes you have to go back to stock and start over. Otherwise you start to get too far out in the rest of the tables. If you're cam is not locked you have to make the same changes to the different cam angle tables as well. It's extremely time consuming, but I can get a large cam to hold the timing as smooth as a stock cam. This is the only way I have found to add significant amounts of timing at idle as well as smooth the idle timing fluctuations.

I believe we are missing tables for idle control. My 17' 1LE idled at 0-2 degrees when it was stock. The first 17' manual Camaro SS I tuned started completely stock before we did bolt ons. That car idled at 10-12 degrees of timing stock. When I compared the two stock files the only difference was the external load table. I copied the SS table to my 1LE tune. Still 0-2 degrees at idle. Both calibrations were identical. Vtt, vve, maf curve all the timing tables, everything was identical, yet the SS idled with 10 degrees more timing.

So for now completely restructuring the torque model is the only way I have been successful at adding timing at idle with large cams.

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Originally Posted by cmitchell17

That being said I have tried a few other things. I rescaled the y-axis on the leading edge angle table for the high pressure fuel pump in effect to model the "32% increase" fuel lobe I have from my cam swap. I was really thinking this might be my issue but so far doesn't seem to have made any difference in anything, I didn't really have any large fluctuations in commanded versus desired high fuel pressure anyway. I also figured, especially since so much timing is being pulled and effecting combustion and combustion stability, that I would cut fuel pressure at idle. This did end up increasing pulse width a couple ms, but unfortunately didn't seem to do anything either.

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I thought that the thing to do for bigger fuel lobes was to multiply the entire 'Fuel Pump Flow Temp Corr' table by your new fuel lobe %.

I hope someone will chime in on this one as I'm curious if I've been doing it wrong. :shrug:

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Originally Posted by g26er

I thought that the thing to do for bigger fuel lobes was to multiply the entire 'Fuel Pump Flow Temp Corr' table by your new fuel lobe %.

I hope someone will chime in on this one as I'm curious if I've been doing it wrong. :shrug:

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scale the y axis is correct
multiply table values is incorrect

I edited this axis by multiplying the entire axis by the increased fuel lobe percentage:
Attachment 98418

So I am assuming the pump doesn't know anything but now the controls have to know that a stroke now displaces 32% more volume than it did stock, what I don't get is how this y-axis even exists it seems like it should just be one constant value, and that value is the displacement volume of the pump, which the aftermarket cam lobe increases by so much percentage.

So I learned this from Greg Banish's GEN V videos, which I really was not too impressed with, however I trust that he would know a lot more than what most people claim to know. There is a lot of information missing from his videos and he basically gives one example. He kind of insinuates, which I know its important to have a correct VVE airflow model, that VVE is the answer to all your problems and that's the only thing you need to do. For example of important left out info, he completely leaves out an explanation of all the torque PID's and how they relate the the tables we have available in HP Tuners.

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Originally Posted by 32vape

When you change the cam you change the air model which changes the torque output. Especially at idle. Torque is greatly reduced at idle with a larger cam. The vtt needs to be changed to reflect this. It takes a lot of time getting this right as it's more of trial and error. Start by unchecking the link selections box and make changes to each table individually. I'll start with reducing the torque by 20% in the rpm, airmass, and map in the idle areas of the -10 and 0 degree tables. Then 15% in the 10 degree, 10% in the 20 degree and 5% in the 30 degree. Larger cams I'll reduce 30% in the lower timing tables and gradient up from there. You also need to smooth the tables out from the idle cells up in rpm, airmass, and map so you don't just have a big chunk of torque removed from the idle areas and stock the rest of the table. Changes also need to be made all at once before you hit the calculate button. And once you calculate that's it. If you need to make further changes you have to go back to stock and start over. Otherwise you start to get too far out in the rest of the tables. If you're cam is not locked you have to make the same changes to the different cam angle tables as well. It's extremely time consuming, but I can get a large cam to hold the timing as smooth as a stock cam. This is the only way I have found to add significant amounts of timing at idle as well as smooth the idle timing fluctuations.

I believe we are missing tables for idle control. My 17' 1LE idled at 0-2 degrees when it was stock. The first 17' manual Camaro SS I tuned started completely stock before we did bolt ons. That car idled at 10-12 degrees of timing stock. When I compared the two stock files the only difference was the external load table. I copied the SS table to my 1LE tune. Still 0-2 degrees at idle. Both calibrations were identical. Vtt, vve, maf curve all the timing tables, everything was identical, yet the SS idled with 10 degrees more timing.

So for now completely restructuring the torque model is the only way I have been successful at adding timing at idle with large cams.

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Thank you for the help. I believe at this point trying to get my VVE more accurate with wideband feedback, given that the ECM is pulling so much timing and therefore effecting combustion and skewing the accuracy of the wideband (I am suspecting I don't know if that's factual but it seems plausible), is going to be a waste of time. For now at least I am going to have to try your instructions and change the VTT.

With all that being said I watched Greg Banish's GEN V videos, which I was not impressed with at all especially for the money they cost. However, he states in the video that you shouldn't be editing the VTT tables independently and that you should leave on the "link selections". I forgot what he was really getting at there but I need to go back and watch the videos again to try to pickup more info I didn't get the first time.

Another interesting point he makes is that the way HP Tuners labels each table as spark=x, spark=x+5, spark=x+10 and so on depending on what you set the spark increments to is actually incorrect by HP Tuners. What I believe he was saying that basically each different spark scenario table is just another table based on how far away you are from the MBT table (which is a table you can adjust in HP Tuners in the ECM which HP Tuners says in their descriptions that adjusting that table is NOT recommended, even though it seems like Banish was recommending it if you have the appropriate mods). So instead of saying spark=0, spark=5, spark=10, I guess it would be like torque when timing is retarded from MBT by x amount of degrees. I would take it that you could go look up whatever is in your MBT table and say its 20 degrees, then you go to the table where HP Tuners says "spark=20" and that would be your torque at MBT. Although I could be wrong?

Anyway I really appreciate your help 32vape, i'm going to go try it now if I can find some motivation.

Does anyone know of a good number to be within to make the airflow model correct on VVE? I've always heard +/-5%, but I am wondering if its good enough? I have doubts about the accuracy of a wideband in trying to get there especially given that we are measuring non-steady state, suboptimal timing conditions.

Instead of using the built in HP Tuners EQ ratio error percentage, I am just using commanded/actual and directly multiplying that number (by half) to the VVE table for correction purposes. This method is recommended by Banish, although it seems like its going to do the exact same thing. I really question my practices especially since nothing will converge. Honestly it seems like I would have better luck blindly adjusting the VVE table up and down at idle speeds until things started looking better.

IMO, it shouldn't be +/- 5% it should be 5% so that is really +/- 2.5% but I like everything negative so I like it between .95 and 1.0 lambda in open loop tuning.

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Originally Posted by Higgs Boson

IMO, it shouldn't be +/- 5% it should be 5% so that is really +/- 2.5% but I like everything negative so I like it between .95 and 1.0 lambda in open loop tuning.

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Thank you Higgs, I agree, even a 2.5% increase at some rpms could cause a very significant airmass and corresponding torque change.

So looking at it a little closer I feel like my VVE correction factors are definitely diverging. I've still been taking histogram logs and trying to correct the VVE table better when I started to notice more of a increase in torque reduction during part throttle shifts, I thought it was from my virtual torque table adjustments I was making by taking away torque at the lower rpms and idle range, but lookin closer I figured out it was cutting power becuase its getting so lean and the timing reduction at the shift is making it basically almost cut out and loose a lot of torque.

Anyway there is something going on. I have the AEM wideband that has the integrated CAN broadcaster and there is a few PID (unit ID's) that I am getting whenever I select to log it and when I try to use it as an input to a math parameter. This is the actual PID I am logging for it and I know this has got to be correct as I can see its picking up its unknown "virtual module":
Attachment 98462 https://photos.app.goo.gl/oELjGuax59FicSKh8

But somehow things in HP Tuners get changed around when you go try to pull PIDs to use in math parameters and other things. I was initially using this PID for the error calculation in the math parameter:
https://photos.app.goo.gl/grdtzsTDTTKXZbda6

But I am not so sure this is the right one so I changed it to this one:
https://photos.app.goo.gl/1qGiC5XTSrFAFXkV6


However whenever I try it both ways it gives me what seems like the same error number that is correct and plausible. So I just don't get it, does anyone else see what else I could be missing or doing wrong? I think I am still having the same problem when I use the generic built-in HP Tuners errors, no matter how many times I log the histogram and reflash nothing just seems to converge?

Just a question are you still running your wideband sensor behind the cat in bank1 position 2

No the wideband is at bank 2 position 1 at the header collector merge.

So I really did'nt give this much though, but I believe what Banish uses in his video is wrong. He says he makes a feedback math to chart in the histogram that is Actual/Desired, which since I am running lean ( I can feel it and my wideband (in lambda) is reading higher than 1). If I take the direct value of actual/desired, and I am running lean, it will always be a number higher than 1, and therefore it will increase the value in the VVE table, and then, since I'm in OLSD will inject more fuel, which should correct the lean condition and go back towards rich, but this hasen't been happening?

Something seems off here and its probably contributing to my problem. So I changed it to desired(commanded)/actual(reading from WB), which should technically be right since say your actual WB reading was .9 lambda (lean) you would multiply that calculated quantity (which would be bigger than one) against your VVE table which would then increase the VVE table values which should then increase your base fueling which would then correct it back to stoich. So I tried this but instead of trying to copy and paste the errors to the VVE, I just multiplied the whole portion of the table I was looking at (under about 2200rpms) by about .9 which is about the average value of the math parameter correction factor on the histogram. This would insure it actually made a change given the errors of calculating coefficients and trying to interpolate missing cells and stuff.

So this made the car read basically that much more leaner at about .72-.73 lambda. So this is obviously going the wrong way, but the really weird thing is I went and smelt the exhaust and I can tell it seems richer, and I can see excess condensation as well (maybe just because it was cooling off and I started it back up).

Anyway so now I am even more confused. My suspicion is maybe I am getting EQ ratio out of my wideband somehow, even though reading the AEM documentation and using logic it seems like the only thing the AEM wideband will send out to the CAN bus is a lambda value? HP Tuners is also showing, when it reads the virtual module created by the AEM controller/gauge the PID shows "WB EQ Ratio 1 (SAE)" but then right next to it it has units of lambda?? I know you can change the gauge output on the AEM to show you EQ, lambda, or AFR, but according to the documentation it appears this is only what the gauge display shows and doesn't change what it reports on the CAN bus, which is what HP Tuners picks up, it appears that only lambda is reported and you can't change it on the CAN bus.

Its almost certain to me that the AEM CAN Bus output that I am reading out in HP Tuners is lambda and this is because I can see the value DECREASE when the PCM enables power enrichment, so this would mean that it has to be lambda. Also going over the discussion by Keith from HP Tuners, he states:

"When describing fuel modifiers, F/A EQ ratio is easy to understand because, increasing the # increases the fuel delivery. An F/A EQ Ratio of 1.2 = 20% more fuel over stoich.

When we use wideband meters, they report in Air/Fuel EQ Ratio.

Wait, what? Widebands report values in Lambda.

Air/Fuel EQ Ratio is the term for the function, who's unit result is Lambda (λ).
Fuel/Air EQ Ratio is the term for a function, who's unit result is Phi (ϕ)."

So just because they use the term "EQ Ratio" it still can be lambda since its "Air/fuel EQ Ratio" and not "Fuel/Air EQ Ratio", they both are called EQ Ratio.

I'm really sorry to keep rambling, but something I just thought of that I think would seem like it would cause problems correcting the VVE table. How is bank 1 and 2 accounted for? I know if you are using fuel trim feedback there is an individual right and left bank PID, and then there is another PID that I would assume is the average of the banks? Now I have heard people recommending getting 2 WBO2s one for right and left banks. So If I am in OLSD, I am assuming the right and left injector banks get exact same fueling command right?

I think I might have to go against the common thinking and say that virtual torque actually needs to be DECREASED at low airmass values. I have been lowering VT at idle region on both airmass and map tables (and E85 since I have E85) and if there is any effect it has the effect isnt very pronounced. I have zeroed out the immediate idle speed adaptive table in hopes that the ECM would abandon trying to control speed/torque through timing and move the throttle blade which I also increased the values for the predicted tables. That looks like that may have helped in that now instead of the timing signature looking so jagged on the logs now it looks more like a straighter line.

Attachment 98764

I have made a math parameter to calculate idle speed error in magenta on top. You can see its somewhat in phase with the spark advance, but if you look at the airmass its definitely completely out of phase with the timing. So when the idle goes overspeed airmass is pulled back and timing is increased towards where it should be. I'm not sure what the behavior is supposed to be when you zero out the immediate proportional speed control gain (I believe in classic "tuning" of a PID controller you are supposed to increase proportional constants until you get oscillation, then start increasing integral control until it damps the oscillation out), but apparently it does this where is seems like there is some major phase lag that will keep the system in oscillation. The good news is it looks like by zeroing the immediate prop constants it has eliminated the jaggedness in the timing which hopefully has made the vibration at idle go away.

At peak spark timing indicated torque parameters are all negative. I don't understand how engine torque can be negative? unless the torque reserve is factored in or some other torque is factored in? If the delievered engine torque at idle was truly negative the engine would immediately die?

I would say at this point my VVE is about as good as I can get it. I know this thing can idle better than it does because at colder starts the idle is a lot better almost stock like, and I don't think its just because the idle speed is raised so much either.

I tuned a procharged/cammed silverado last week and the single best thing i did was raise the idle rpm to 850, I still had some idle surging and found that the previous tuner adjusted the etc scalar, i put that back to stock and the truck idles perfect now. It took me a good day or so to get it to where I was happy, but those to changes made the biggest difference.

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Originally Posted by cmitchell17

I think I might have to go against the common thinking and say that virtual torque actually needs to be DECREASED at low airmass values.

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I've been saying this for months in random threads lol. I don't know if it is the correct way to do things, but it definitely has an effect on idle and part throttle timing meaning if you lower these values the car will not be pulling timing. Basically lowing the VT tells the car its making less torque so it doesn't try to pull timing out to bring the torque value down. Now this also makes me think we still don't have defined tables that show what the torque limit is per RPM before it starts pulling timing.

I have also been messing with the Increasing Torque Rate limits in the Driver Demand section and I THINK this also has an effect on how much Torque Management Advance is active on idle and part throttle pedal movement. Meaning if you raise the values, TMA kicks in less just off idle. I was testing this on a ported throttle body and so far have seen lower TMA values when taking off from a stop light vs leaving these tables stock. But I don't have enough yet to say this is actually the case.

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Originally Posted by ZincGT

I tuned a procharged/cammed silverado last week and the single best thing i did was raise the idle rpm to 850, I still had some idle surging and found that the previous tuner adjusted the etc scalar, i put that back to stock and the truck idles perfect now. It took me a good day or so to get it to where I was happy, but those to changes made the biggest difference.

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So I agree with a cam there is a certain rpm you can hit to where everything just goes back to normal like magic. I mean this is obviously got to do with larger cams and overlap and combustion stability and EGR effect, but its really surprising that it goes from so rough to almost stock in a few rpms, you would think it would take more rpms. Problem is then you lose the cool sound (which will probably eventually annoy me haha) and then you lose some driveability in parking lots, and unfortunately your car still sounds broken to people who don't know what a cam is haha. Thats kind of my main goal to not be embarrassed by making people think my brand new car is broke haha.

My problem is I've been chasing all this rough idle issues with a cam, but I don't even know what I should expect with a cam, maybe I can't expect any better idle quality that I already have? I see my wideband jump all over the place sometimes, one day I will take a log to tune VVE and it will be rich, I will correct it and it will be good and normal, the next day its right back to rich, correct it and its normal, then the next day its lean? Makes me think it may be bad combustion stability, I can log misfire counts and see some counts 10-20 in a glance of looking down at the scanner, but I have the same problem, how much is "normal"? We just don't have the right tools to actually really know whats going on, so I could be wasting my time getting myself frustrated because maybe I am getting a false lean condition because of the excessive misfires is letting too much pure oxygen out the exhaust? We just don't have any way to tell.

I may go revisit idle speed again, but I have another problem, the dynamic testing tools are so buggy you can't use them. Sometimes the idle speed control works, but the idle spark correction bypass (whatever this is supposed to "bypass" I'm not entirely sure) or the timing advance override/control I have never been able to get to work, I am not sure if maybe it doesn't work when the airflow model or torque correction is off by so much or what but I have never seen it do anything.

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Originally Posted by TriPinTaZ

I've been saying this for months in random threads lol. I don't know if it is the correct way to do things, but it definitely has an effect on idle and part throttle timing meaning if you lower these values the car will not be pulling timing. Basically lowing the VT tells the car its making less torque so it doesn't try to pull timing out to bring the torque value down. Now this also makes me think we still don't have defined tables that show what the torque limit is per RPM before it starts pulling timing.

I have also been messing with the Increasing Torque Rate limits in the Driver Demand section and I THINK this also has an effect on how much Torque Management Advance is active on idle and part throttle pedal movement. Meaning if you raise the values, TMA kicks in less just off idle. I was testing this on a ported throttle body and so far have seen lower TMA values when taking off from a stop light vs leaving these tables stock. But I don't have enough yet to say this is actually the case.

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I have raised the values and tried maxing them out. I haven't notice much difference besides if you max out the decreasing torque table you get extremely annoying and bad NVH problems from the driveline when coasting/cruising, when you let off the wheels immediately being to drive the engine it takes up the backlash in the pinion and makes the awful extremely annoying clunk that makes the car feel cheap a lot more evident.

In my case I do acknowledge we can get higher average timing at idle, it has worked a little for me. By adjusting the idle/low airmass cells (<1000 rpms/<300grams/<70kPa) by about 75ft lbs and then slowly not decreasing as much as you get higher on spark (like how 32vape suggested) it works to bring idle up to about 10-15 sometimes 20, I think given the cam we need above 30 to ensure complete combustion but that is my speculation with no evidence or proof (we dont' have combustion analyzers or in cylinder pressure testers). I think if I go any more above about 100 ft lbs decrease it screws up the speed control and the idle speed will slowly start oscillating.

I still am a really firm believer and it seems like common sense that the torque tables do not need adjusting. If the cam is less efficient at lower rpms because the intake valve is open too long and its allowing fresh air charge to bleed off back into the intake manifold then the MAP and MAF should pick this up as a lower airmass in the cylinder and the torque table should reference a lower cylinder airmass in its tables and indicate a torque value less than stock and everything should be fine. I don't know maybe when you have a bigger cam than stock with the longer exhaust duration and late exhaust valve closure it maybe needs even more reduction in virtual torque than what's on the stock tables? since the stock tables are obviously designed with the stock cam? So maybe I am not really correct in my assumption?

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Originally Posted by cmitchell17

I have raised the values and tried maxing them out. I haven't notice much difference besides if you max out the decreasing torque table you get extremely annoying and bad NVH problems from the driveline when coasting/cruising, when you let off the wheels immediately being to drive the engine it takes up the backlash in the pinion and makes the awful extremely annoying clunk that makes the car feel cheap a lot more evident.

In my case I do acknowledge we can get higher average timing at idle, it has worked a little for me. By adjusting the idle/low airmass cells (<1000 rpms/<300grams/<70kPa) by about 75ft lbs and then slowly not decreasing as much as you get higher on spark (like how 32vape suggested) it works to bring idle up to about 10-15 sometimes 20, I think given the cam we need above 30 to ensure complete combustion but that is my speculation with no evidence or proof (we dont' have combustion analyzers or in cylinder pressure testers). I think if I go any more above about 100 ft lbs decrease it screws up the speed control and the idle speed will slowly start oscillating.

I still am a really firm believer and it seems like common sense that the torque tables do not need adjusting. If the cam is less efficient at lower rpms because the intake valve is open too long and its allowing fresh air charge to bleed off back into the intake manifold then the MAP and MAF should pick this up as a lower airmass in the cylinder and the torque table should reference a lower cylinder airmass in its tables and indicate a torque value less than stock and everything should be fine. I don't know maybe when you have a bigger cam than stock with the longer exhaust duration and late exhaust valve closure it maybe needs even more reduction in virtual torque than what's on the stock tables? since the stock tables are obviously designed with the stock cam? So maybe I am not really correct in my assumption?

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I don't mess with the decreasing values at all since that parts works well on the OEM values 99.999999999% of the time. I only change the increasing.

You're thinking is right from a mechanical standpoint but not from a tuning standpoint on the valve overlap at low rpms with a bigger cam. But with a larger cam you idle with less vaccuum because of it so the ECU sees a highe MAP value of say 65kpa instead of 30kpa but the Airmass values from the MAF aren't off as much and manifold vacuum is mostly irrelevant to the MAF(unless you get a real big cam and reversion is an issue). Since the ECU uses MAP and Airmass(derived from MAF and sometimes referenced by MAP) to lookup the torque tables it gets confused. You have to go into the MAP VT tables and shift all of the values you would normally see at idle areas for the 30-35kpa range and move them up to 60-65kpa range (depending on cam size). Then what is also interesting is just off idle with the cam your manifold vacuum actually increases meaning the MAP measures a drop in kpa for a moment even though you just stepped on the gas pedal. This creates a kind of hooking reference lookup on the MAP based tables instead of a linear increasing MAP value with RPM. So you have to account for this in VVE as well. I would recommend you graph MAP and AIRMASS vs RPM in the scanner and watch how they both move across the tables differently. You might find you need a higher VVE value at 45kpa at 1200-1600 RPM than you do at say 65 kpa at 1200 rpm. If your cam is locked at 0 then it will make this part way easier as you only have one VT table to tune.

Quote:

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Originally Posted by TriPinTaZ

I don't mess with the decreasing values at all since that parts works well on the OEM values 99.999999999% of the time. I only change the increasing.

You're thinking is right from a mechanical standpoint but not from a tuning standpoint on the valve overlap at low rpms with a bigger cam. But with a larger cam you idle with less vaccuum because of it so the ECU sees a highe MAP value of say 65kpa instead of 30kpa but the Airmass values from the MAF aren't off as much and manifold vacuum is mostly irrelevant to the MAF(unless you get a real big cam and reversion is an issue). Since the ECU uses MAP and Airmass(derived from MAF and sometimes referenced by MAP) to lookup the torque tables it gets confused. You have to go into the MAP VT tables and shift all of the values you would normally see at idle areas for the 30-35kpa range and move them up to 60-65kpa range (depending on cam size). Then what is also interesting is just off idle with the cam your manifold vacuum actually increases meaning the MAP measures a drop in kpa for a moment even though you just stepped on the gas pedal. This creates a kind of hooking reference lookup on the MAP based tables instead of a linear increasing MAP value with RPM. So you have to account for this in VVE as well. I would recommend you graph MAP and AIRMASS vs RPM in the scanner and watch how they both move across the tables differently. You might find you need a higher VVE value at 45kpa at 1200-1600 RPM than you do at say 65 kpa at 1200 rpm. If your cam is locked at 0 then it will make this part way easier as you only have one VT table to tune.

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Sorry for not responding I haven't forgotten about this post, because I really really think you are on to something here. However, trying to just copy the 30kpa values to the 60kpa values in the MAP Virtual Torque tables I can't get to work. I tried copying them and interpolating until the ends of the graph to smooth the transition and then interpolating horizontal as RPMs increase, but when I extrapolate coefficients button to calculate, it gives me a bad solution that looks basically the same as before I started. Also if we copy the values from 30 kpa, do we leave the values at the 30kpa cells the same?

I get the point of this and that is to look at what we idled at stock with the stock cam, and say its around 30 kpa, so we know that that MAP referenced airmass is how much air and therefore torque it took to balance everything out at idle, so we just move that to where the aftermarket cam will idle which is at less vaccum and higher MAP?

What you are describing TriPinTaZ I think is exactly what is happening here:

Attachment 99190

I see this a lot in my VVE tuning logs, you can see its linked in the scan tool to a normal MAP range (.56), but every now and then the idle will blip up to the .70 range and the timing will spike and this is my problem, this is when I get the surge and annoying bucking, then it goes back down, and of course during open loop speed density the wideband fueling is showing 10% lean.

Something is causing it to hook like you said when its referencing cells, I am just so confused right now I can't really think about what's going on. I still have a strong feeling that the torque model dosen't need to theoretically be changed, but I think its just overlap, reversion, EGR effect, etc on bigger cams is causing anomalies like this.

Just as a way to experiment, if I put 0 rpm in the High RPM Disable table for dynamic airflow would it go MAF only, and therefore I could see if this problem is still occuring? I think I may have tried this before, but im wondering if it will still use MAP for torque calculation? What if I unplugged the MAF sensor?

I am too fighting my VVE similar to you with some lean ridges and idling issues with a larger cam which lead me to this post. In your post from two weeks ago you mention the exhaust smelled richer when lambda went lean at 0.72-0.73 lambda.

Anything less than 1.0 lambda is rich and over 1.0 lambda is lean. That's the way I understand it and that would explain the exhaust smelling richer.

Just trying to help and understand at the same time.

In the simplest terms you will need to reduce VVE in the Idle(600-900rpm) and off idle(1000-1200) areas. You don't necessarily need to copy the values from 30kpa and paste in 60kpa. Instead, lower the new idle area in VVE starting at 20-30%. But before you make any changes, click on the "show zone numbers" to see the boundaries, then uncheck it and ONLY lower the values inside a section at a time or you will often get the errors you are describing. You should be editing Manifold Switch OPEN in the drop down. Once you are done you can paste the same values into the Manifold Switch CLOSED table but I never do, at least not on LT1/LT4 cars.

SO think about it this way, editing by section as described above.
#1) What is the value in the VVE idle area pre-cam? What is the value in the new idle areas post cam? Is the difference about 10% 20% 30%? Lower the idle section in VVE by the estimated difference(I wouldn't exceed 30%).
#2) When you tap the throttle and the car comes just off idle, look at the same thing above, pre cam VS post cam. Off idle due to increased overlap(and the aftermarket cam locked at 0 movement) there will be a lower Volumetric Efficiency for this area as well compared to stock. And the cells movement in the scanner, meaning your vacuum increases so KPA goes lower(less than idle) temporarily. This area is likely also less efficient than stock with the new cam and needs to be lowered but not quite as much as you would at idle. You really want to just start with a base of going from say 30% reduction at idle rpm and scaling towards 0% reduction near 2000 RPM. This is a rough estimate to get you in the ballpark so that it is driveable.

As for the "hook" that is the new cam overlap with zero cam movement. MAP values behave differently because science of air pressure and such lol. Think about the below example to sort of see what I am talking about.

Stock Cam:
-Idles at 600 rpm with a MAP value of 30kpa. You tap the throttle and the RPMs climb to 1500 and MAP moves linearly from 30kpa to 70kpa in an increasing manor. This is due to low overlap in stock cam which is even more reduced due the cams ability to move around.

231/246 Aftermarket Cam:
-Idles at 850 rpm with a MAP value of 60kpa. You tap the throttle and the RPMs climb to 1700 and MAP moves from 60kpa down to 45kpa then back to 70kpa in sort of a bump then fish hook(looking at the scanner) manor.


For these reasons alone the OEM VVE tables are wrong. So after the cam you might find the 1200 rpm area at 40-50kpa needs to increase and the 1200rpm area at 50-60kpa needs to decrease, and then at 1200rpm 70-90kpa needs to increase. I know this is all a bit weird to type out without charts etc. But lets forget the complications of tuning Gen V stuff and think about the physical operation of the engine. Even from the very first small block until now, even far more advances, the laws of physics still apply. Supercharges and Turbos add another level of complexity to the VVE but not in the sense where it behaves any differently than other cammed blower/turbo cars.

Quote:

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Originally Posted by MattofEarle

I am too fighting my VVE similar to you with some lean ridges and idling issues with a larger cam which lead me to this post. In your post from two weeks ago you mention the exhaust smelled richer when lambda went lean at 0.72-0.73 lambda.

Anything less than 1.0 lambda is rich and over 1.0 lambda is lean. That's the way I understand it and that would explain the exhaust smelling richer.

Just trying to help and understand at the same time.

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I too get really confused with it sometimes, but after a while your brain starts to get used to thinking in EQ. Here is a good link where Chris @ HP Tuners explains it in good detail:

https://forum.hptuners.com/showthrea...EQ)-Discussion

Quote:

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Originally Posted by TriPinTaZ

In the simplest terms you will need to reduce VVE in the Idle(600-900rpm) and off idle(1000-1200) areas. You don't necessarily need to copy the values from 30kpa and paste in 60kpa. Instead, lower the new idle area in VVE starting at 20-30%. But before you make any changes, click on the "show zone numbers" to see the boundaries, then uncheck it and ONLY lower the values inside a section at a time or you will often get the errors you are describing. You should be editing Manifold Switch OPEN in the drop down. Once you are done you can paste the same values into the Manifold Switch CLOSED table but I never do, at least not on LT1/LT4 cars.

SO think about it this way, editing by section as described above.
#1) What is the value in the VVE idle area pre-cam? What is the value in the new idle areas post cam? Is the difference about 10% 20% 30%? Lower the idle section in VVE by the estimated difference(I wouldn't exceed 30%).
#2) When you tap the throttle and the car comes just off idle, look at the same thing above, pre cam VS post cam. Off idle due to increased overlap(and the aftermarket cam locked at 0 movement) there will be a lower Volumetric Efficiency for this area as well compared to stock. And the cells movement in the scanner, meaning your vacuum increases so KPA goes lower(less than idle) temporarily. This area is likely also less efficient than stock with the new cam and needs to be lowered but not quite as much as you would at idle. You really want to just start with a base of going from say 30% reduction at idle rpm and scaling towards 0% reduction near 2000 RPM. This is a rough estimate to get you in the ballpark so that it is driveable.

As for the "hook" that is the new cam overlap with zero cam movement. MAP values behave differently because science of air pressure and such lol. Think about the below example to sort of see what I am talking about.

Stock Cam:
-Idles at 600 rpm with a MAP value of 30kpa. You tap the throttle and the RPMs climb to 1500 and MAP moves linearly from 30kpa to 70kpa in an increasing manor. This is due to low overlap in stock cam which is even more reduced due the cams ability to move around.

231/246 Aftermarket Cam:
-Idles at 850 rpm with a MAP value of 60kpa. You tap the throttle and the RPMs climb to 1700 and MAP moves from 60kpa down to 45kpa then back to 70kpa in sort of a bump then fish hook(looking at the scanner) manor.


For these reasons alone the OEM VVE tables are wrong. So after the cam you might find the 1200 rpm area at 40-50kpa needs to increase and the 1200rpm area at 50-60kpa needs to decrease, and then at 1200rpm 70-90kpa needs to increase. I know this is all a bit weird to type out without charts etc. But lets forget the complications of tuning Gen V stuff and think about the physical operation of the engine. Even from the very first small block until now, even far more advances, the laws of physics still apply. Supercharges and Turbos add another level of complexity to the VVE but not in the sense where it behaves any differently than other cammed blower/turbo cars.

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Here is my VVE table, this is after months and 100+ logs of refinement. I have been using Bluecat's tool to calculate the table. First I use the VVE editor in HP Tuners to copy and paste the scanner feedback. Then I use the VVE editor to interpolate horizontally (since I can more safely assume linearized behavior between RPM, rather than interpolate vertically since I think you get more non-linear behavior through RPM). This get it more filled out. Then I use Bluecat tool to calculate the coefficients and if any come back above the integer hard limit in the tune file, I have to smooth. I try not to smooth too much because I think it takes out what you are trying to do. What I like about the Bluecat tool is that it will adjust the zone boundaries as well as a variable to get even more accuracy:
Attachment 99232

It may be worth it for me to go back to the stock VVE and do exactly as you said increase the 40-50Kpa area a certain percentage, decrease the 50-60kpa by a certain percentage, then increase the 70-90KPa a certain percentage. When you watch the O2 or fuel trim feedback in the histogram and watch the cells its referencing, you can see it kind of go in a circle or that J-hook think like you said. The drastically different cells it references, along with all the other modifiers very well could lead to some negative feedback loop causing instability which causes the timing to spike around.

Would you mind sharing what your VVE table looks like?

Quote:

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Originally Posted by cmitchell17

Here is my VVE table, this is after months and 100+ logs of refinement. I have been using Bluecat's tool to calculate the table. First I use the VVE editor in HP Tuners to copy and paste the scanner feedback. Then I use the VVE editor to interpolate horizontally (since I can more safely assume linearized behavior between RPM, rather than interpolate vertically since I think you get more non-linear behavior through RPM). This get it more filled out. Then I use Bluecat tool to calculate the coefficients and if any come back above the integer hard limit in the tune file, I have to smooth. I try not to smooth too much because I think it takes out what you are trying to do. What I like about the Bluecat tool is that it will adjust the zone boundaries as well as a variable to get even more accuracy:
Attachment 99232

It may be worth it for me to go back to the stock VVE and do exactly as you said increase the 40-50Kpa area a certain percentage, decrease the 50-60kpa by a certain percentage, then increase the 70-90KPa a certain percentage. When you watch the O2 or fuel trim feedback in the histogram and watch the cells its referencing, you can see it kind of go in a circle or that J-hook think like you said. The drastically different cells it references, along with all the other modifiers very well could lead to some negative feedback loop causing instability which causes the timing to spike around.

Would you mind sharing what your VVE table looks like?

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PM'd you

following along here as in the same boat now as did a cam and heads on my 17 zl1. Seeing a lot of the same issues on mine but with a pd supercharger that also is affecting the kpa at idle vrs if yours is N/A as mine is naturally higher due to over spinning it. So adding the cam took that up another notch. Going back to a stock vve today and start over in idle cells. That is if can get this thing into sd and not get reduced power as that seems to be random if will work or not.

so 30 attempts at vve as it kept wanting me to pull 10 percent every time I re wrote it and did a log I got it to idle at .95/1.00 so ill call that a good vve but yet timing is -6 to -12. I tried everthing up on vt down on vt i tried to hammer it with 50 percent on the main eq table both ways and adjust it in the virtual torque edtor just trying to push it one way or another. I tried small adjustments first I went down to 675 on the idle tring to force it to use torque to make it idle. So bounced from 750 to 675 I tried all the idle torque settings. all most of it did was move around the idle make it more unstable or stay with in what I was shooting for but all of it had low timing in the -5 and lower. At one point I put the stock throttle body scaller back in it and when it started it was at 13 degrees and sounded great for about 8 seconds then back to the shit idle with no timing. Its around 700 rpm . 75 kpa and .50 airmass when its at the lower timing. If timing crosses over 10 it will drop the airmass to .30 range and kpa to the 60s. This is also a blower cam with 0 overlap on a 118 while its 227-244 it does idle very good when it has timing in it. So I will say getting the vve correct is not the answer to this. Last time I did this it wouldnt idle with any timing until I added the maf back into it then it had like 3-6 degrees on the same tune that had -10 with sd only. Funny thing is lean on the throttle just a touch and it will drop the airmass raise the timing and kpa goes down. Gets really good with a tiny bit of throttle input so thought maybe this is in the driver demand so messed with that too. I put a few settngs on differnt maps and didnt do much of squat when changing between them. Will play with it more and report back if hit on something that can help.

Try raising the Peak Torque table in the idle RPM ranges and reducing your VT table by 20% in idle area and blending to a lower reduction as RPMs go up. If your cam isn't moving any then you would just have to edit one VTT table. You might need to adjust your SOI & EOI now for the cam as well.

Technically Driver Demand shouldn't affect idle stability while stationary because at 0% driver pedal its requesting no torque or negative torque. You can test this by changing the 0% pedal / 0 mph column to 0 or lower and see if it has an effect on idle torque requested but I doubt it.

Quote:

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Originally Posted by TriPinTaZ

Try raising the Peak Torque table in the idle RPM ranges and reducing your VT table by 20% in idle area and blending to a lower reduction as RPMs go up. If your cam isn't moving any then you would just have to edit one VTT table. You might need to adjust your SOI & EOI now for the cam as well.

Technically Driver Demand shouldn't affect idle stability while stationary because at 0% driver pedal its requesting no torque or negative torque. You can test this by changing the 0% pedal / 0 mph column to 0 or lower and see if it has an effect on idle torque requested but I doubt it.

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I did add to the soi table but didnt touch the eoi. I looked at my cam events vrs the stock ones when I used a wallace calculator to get actual timing events and saw that I now have a larger window but its moved back quite a bit towards top dead center. My intake valve opening is around 1 degree before tdc vrs stock which was out at 20 i believe so common sense looking at how the stock cam is setup I should now move my soi back the same amount of degrees as my cam is moved? Its so hard to find the right way to do any of this and so many wrong ways posted out there. The banish video I watched didnt cover it the greatest so just tried to move the soi the same amount that my cam now has moved the intake opening.
Seems like no matter what I was doing if I am in SD that it will always revert back to around -10. It might do a cold start and have 20 degrees of timing and sound great but with in 20 -30 seconds its back to retarding it. I thought maybe changing the 0 value in the driver demand would help it by commanding a differnt torque reading but I only tired higher I didnt try lower then stock. Whats odd is when i re induce the maf back into the tune I then have closer to 0-5 degrees of timing in it. Im going to have to street tune the vve which I know is a pain and so hard to hit enough cells to make a good table i was attempting this on the bolt ons as the ported blower had it so far out of wack.
Seems no matter what I do in SD it wants to raise up the cylinder airmass to .50-.60 vrs when maf is in play its around 30 closer to stock .20 and of course makes it idle much better when getting that lower. I even put my high side pump to 300 psi as it was throwing 1500 plus at it when airmass is too high. It seems to be more important to get that cylinder airmass back down closer to stock so more of the tune lines back up. Even the mbt timiing table will be so jacked up if cylinder airmass is out over .30
This cam has no overlap its actually -.05 and on a 118 so i didnt expect so much grief from it trying to get the idle correct. I have played with other cars that people couldnt get to idle right or didnt attempt it with cams on a 114-116 with more over lap and had no issues getting it to idle with some timing. But then I never put any of those into SD either I was just trying to help a friend or someone get the tune a little more stable and drive better and not "Tune" the car correctly which is what I am attempting now on my own car. So big differnce in patching someone elses tune to work vrs doing it correctly or what you think is right by tons of info out there which much of it could be leading you in the wrong direction. Why I watched the banish video hoping for some more on all of this. good tips there but doesnt go into it as much as hoped.
This is nothing like gen 3/4 like he enjoys saying over and over as every small change on this platform will affect another. With out being able to look at a log and understand what the data is telling you to make the right changes is the biggest challenge. This is nothing like wot tuning or even part throttle which yes is more like other platforms at least gen 4 when comes to making the transmission work well with using virtual torque but that is about it.
Thanks for help from those that comment. Hoping I can help myself and the original poster here with replys as not trying to hijack his thread when having the same issues.

so after screwing with it all day and watching a few vidoes over I did manage to get a decent idle from it in SD holding some timing. Im commanding 750 but its staying under that and it sounds good even with only 5-10 degrees of timing in it. But when I put it into park It goes up to 750 pulls on the brakes the kpa shoots up the cylinder airmass shoots up and it goes back to -10 degrees so not sure what Im misssing on it.
Im trying to get it good enough just to do some logging and get the vve dialed in or attempt it anyway as some things I see just dont seem right.
I have it in open loop and it says open loop not ready yet its logging stft still where the ltft is showing 0 so not sure if that is right or not.
Then with the maf failed and on first error like typical early it goes to reduced power. So I then set it up to not report any errors and then it stays out of reduced power BUT its still showing maf HZ on the log so its still logging it. I went as far as unpinning the green and white wire so that I saw no reading on the log so that way I know the maf is not in play here still. Maybe over kill but I didnt like seeing it read as the same with the stft I dont like seeing it pretty much in line with what my wideband is saying which tells me the stupid thing is stull using trims. I guess the only verifcation its not is that the widebnd will not try to center at commanded and it is reading rich or lean if the vve is off in that area. Just very odd that it is still reading fuel trims though not using them same with Maf.
So took me like 30 trys to nail the park/neurtal down so if some one could check out my tune and log possibly and give some pointers on it.
I have found that once cylinder airmass goes up over 50 it screws with all kinds of stuff. The cam having no overlap I thought I was going to see better vacuum/kpa but maybe the blower is skewing it more then I thought it would as im idling around 73 kpa in parrk and goes up to 85 in gear and it gets all screwy at that point. On the log you can see it go between in and out of gear and go from a decent idle to shit when its got the added load on it.
Thanks for any help here on it

Got it almosst decent but still wont hit my target idle and it is all over though I finally got enough timing to not glow the headers in both park and in gear. Any advice off my log and tune would be great.

What threads are you reading to learn how to adjust the SOI tables????

Quote:

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Originally Posted by Jonblarc7

What threads are you reading to learn how to adjust the SOI tables????

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I had read a few on here and one of them had a chart someone had made that I had printed out and its has all the cam events on it. think it was called camshaft and injector timing. I also watched the greg banish gen v tuning videos.
After fighting some of it and it kept going into limp I got it to where i could actually drive the damn thing and after about 3 revisions its really good for the driving part anyway. Numbers are not perfect some cells I have showing 10 percent rich still but car is driving great on it right now. trans is clicking off firm shifts no longer lazy feeling at low and part throttle. Wot was still a little rich buit car felt good. Started to rain so waiting on that now to get back at it. I am not going to be so concerned with all of it being perfect as I will run it in maf most likely anway but more about how it drives and the fact it drives great right now other then rich off throttle which I am going to fix I feel confident that when add the maf back its going to be really good. the more I drive it the more stable the idle got too and added some timing to it on its own vrs doing a change then write car and test write test write test where went much of no where once I got to around 0 plus or minus 5 degrees. Now I was seeing upwards of 18 degrees at idle and it was not pulling on the brakes as its idleing around 650 and seems to be fine with it.

Quote:

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Originally Posted by lt1z350

Got it almosst decent but still wont hit my target idle and it is all over though I finally got enough timing to not glow the headers in both park and in gear. Any advice off my log and tune would be great.

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Apply the same VT changes to the E85 MAP and Airmass

so I had it pretty good and was driving on it for a few days and it was pretty hot out side here. Still not the amount of timing I want in it and cannot seem to make it increase the timing no matter If I go up or down on the virtual torque. What sucks is it drives even better then stock on what I have done to the virtual torque and vve.
Then yesterday we have a temp drop goes into the 70s and it starts hunting bad in gear. Its fine in park but pull it into gear and hunts like crazy up to 1200 sometimes and trys to drive off. Im on tune 30 this morning trying to make it go away and though I can see all these values move around and it change with each addation to torque or reduction it will still contiune to hunt in gear. Same thing as before lean on the throttle a little so push the pedal the tps goes down timing comes up kpa down airmass down and idle drops to a steady 550 push a tad more I can make it idle so good in gear but all it seems to be doing it closing the throttle and adding timing and the rest is working itself out.
You try to make sense of it looking over stock vt tables and say the car idles at .14-.20 airmass 35-40 kpa (pd blower) but only delivering -14 engine torque low tps around 12 percent or less and has 8-10 degrees. You try to wrap your head around all that on stock tables and think you make sense of it but yet trying to adjust the vt to that its not helping it. i can have it steady in park and pull into gear and hunts so bad it will try to run off. None of this happened until I had a temp swing out side. I never got it perfect as can never get the timing I want in it but not this hunting you cant even drive.So something is drasticly changing when transmission load is added to it and causing it to start trying to add all this timiing and torque for no reason that isnt there with no load. Its become baffling as it drives so good yet idle is just fighting me.