98 Camaro SS - 2nd Tune Attempt -> In need of guidance I'm afraid

[MikeyZ28SS]

Hi,

Newbie tuner in need someone with experience to take a look at this one. Narrowband tuning (No Wideband yet) I'm not sure my LTFT tuning changes are doing anything... Config or setup missing something? Resetting fuel trims by disabling, flashing, then loading the tune. Scanning using only VE - LTFT & STFT, No MAF channels. But when I make changes not seeing LTFTs move much if at all.

What am I missing here?

Thanks!
Mikey

17-09-20 17-46-01.hpl
1998 Camaro Fuel Trim Tuning.Channels.xml
98 SS Tune 05 Maxed - MAF Fail 4 LTFT Tuning.hpt

[MikeyZ28SS]

Bump... Review and comment anyone?

[AutoWiz]

If you want to tune your ve table you need to set your maf fail high hz to 0 under engine diagnostics > airflow. Then under engine > fuel you need to disable DFCO, PE, and COT. These things kick in at unannounced times and can provide you with bad o2/ fuel trim data. write that to the vcm and now as long as you have the right injector size programmed, hopefully you will see changes made to your ve table on the next log. Don't forget to reset fuel trim after making changes before logging more data or you might be chasing your own tail. Also under engine > airflow > dynamic you might want to set the high rpm disable to 7k rpm so you can tune past 4,000rpm. You can put all these values back and enable everything when your fuel trims are all looking good.

Once your ve table is good and you have fuel trim data all in the -3 or less range, the next step before you put everything back together is to set high rpm disable to a very low number like 200 under engine > airflow > dynamic and then set maf fail high hz back to 13,500 or w/e you had it at under engine diagnostics > airflow. Now you can do to your maf sensor calibration exactly what you did to your ve table. You will find that table under engine > airflow > general right next to the ve table. you shoot for the same goal here, Until all cells report back -3, -2, -1, or 0. Remember to keep resetting fuel trims in between logs and changes and keep looking at your tables in 3d or 2d chart view and make sure as you make changes things stay smooth.

[Area47]

disabling pe is not advised. it does not kick in at "unannounced times. This is triggered by set parameters.

[AutoWiz]

hey fool, when the pe kicks in it commands the afr outside what his o2 sensors can see. And it's not advised by whom? you?

With everything disabled you do all your idle and part throttle tuning until you have a known good ve table and maf. then you put it all back together and start tuning for wide open throttle. But you DON'T want to be in power enrichment when you are trying to tune your ve table. especially off of LTFT or any data from your narrowband o2 sensors. Let's hope area47 reads the whole thread before any further posts.

[5FDP]

Um, you can just raise the PE enable feature to above the normal without disabling while still leaving them active and still having the safety net there if you had to hammer on it. You'd just have to redo your data logging if that happened.

Part throttle won't enter PE so no need to disable that.

[Area47]

hey fool, when the pe kicks in it commands the afr outside what his o2 sensors can see. And it's not advised by whom? you?

With everything disabled you do all your idle and part throttle tuning until you have a known good ve table and maf. then you put it all back together and start tuning for wide open throttle. But you DON'T want to be in power enrichment when you are trying to tune your ve table. especially off of LTFT or any data from your narrowband o2 sensors. Let's hope area47 reads the whole thread before any further posts.

I would suggest you stop posting before your made a fool of.

5FDP is correct.

[AutoWiz]

but if I didn't post that then this guy would be trying to tune his ve table with pe commanding his o2 sensors to just read 900+mv. Good thing that I corrected your information here, huh?

[Oleblu]

For a little more clarification I would say disabling pe is not advised for anyone trying to tune on the street without the comfort of using a dyno. There is much less control over the amount of variables that can and should be taken into account. Its much easier to adjust the thottle enable percentage above your normal part throttle driving usage.

[Area47]

but if I didn't post that then this guy would be trying to tune his ve table with pe commanding his o2 sensors to just read 900+mv. Good thing that I corrected your information here, huh?

You set up filters to remove the PE from the equation. problem solved. you have failed to correct anything, but only to suggest risking an engine without properly evaluating the situation and how to avoid it.

[AutoWiz]

for A LOT more clarification, log and watch your kr sensors. if you are creating noise at 14.7 but not at 12.5 then maybe you got a bit too happy with your ignition timing. Generally a well tuned engine needs more than 2pts in either direction before you get kr, but you all seem like you have such great ideas and thoughts on the subject.

[GHuggins]

Trying to get back on track here... I would start by multiplying your entire VE table by 25%, but I'm not sure you even have it in SD mode... Set MAF Hz to 1 and then after starting verify with the scanner that it has indeed set a DTC for the MAF... You can also log air calc mode - should be Normal if it's in SD and then high speed for MAF if memory serves on these... That might possibly take care of a lot of your issues... Also don't forget to copy with axis on the VE map and then paste into your secondary VE map to keep them the same...

IF and I do mean "IF" you use the keep it in closed loop method - make sure your O2's are correct and not giving you false information - common with headers or air adders changing your airflow calculation tables for the O2's and then make dang sure to pull 10 to 15 degrees out of the spark table AND THEN do like previously stated and design in further safeties such as going into PE still with anything over 80% calculated PE pedal "not to be confused with regular pedal"...

[MikeyZ28SS]

Okay, so trying to digest a lot of good info, and sort it into a sequence of operations/tasks. Please review and edit / revise If I didn't capture it correctly. Well, here goes;

Tuning Sequence:
To tune your ve table you need to set your maf fail high hz to 0 under engine diagnostics ( Set MAF Hz to 1 and then after starting verify with the scanner that it has indeed set a DTC for the MAF... You can also log air calc mode - should be Normal if it's in SD and then high speed for MAF ) > airflow.

Then under engine > fuel you need to disable DFCO, PE ( raise the PE enable feature to above the normal without disabling while still leaving them active and still having the safety net there if you had to go WOT ), and COT. Start by multiplying your entire VE table by 25%

Write that to the vcm and now as long as you have the right injector size programmed, hopefully you will see changes made to your ve table on the next log.

Log and watch your kr (Knock Retard) sensors. if you are creating noise at 14.7 but not at 12.5 then maybe you got a bit too happy with your ignition timing. Generally a well tuned engine needs more than 2pts in either direction before you get kr. You can also log air calc mode - should be Normal if it's in SD and then high speed for MAF

Don't forget to reset fuel trim after making changes before logging more data or you might be chasing your own tail.
Also under engine > airflow > dynamic you might want to set the high rpm disable to 7k rpm so you can tune past 4,000rpm.
You can put all these values back and enable everything when your fuel trims are all looking good.

Once your ve table is good and you have fuel trim data all in the -3 or less range. Don't forget to copy with axis on the VE map and then paste into your secondary VE map to keep them the same.

The next step before you put everything back together is to set high rpm disable to a very low number like 200 under engine > airflow > dynamic and then set maf fail high hz back to 11,250 or w/e you had it at under engine diagnostics > airflow.

Now you can do to your maf sensor calibration exactly what you did to your ve table. You will find that table under engine > airflow > general right next to the ve table. you shoot for the same goal here, Until all cells report back -3, -2, -1, or 0.

Remember to keep resetting fuel trims in between logs and changes and keep looking at your tables in 3d or 2d chart view - and make sure as you make changes things stay smooth.

With everything disabled you do all your idle and part throttle tuning until you have a known good ve table and maf. then you put it all back together and start tuning for wide open throttle. But you DON'T want to be in power enrichment when you are trying to tune your ve table. especially off of LTFT or any data from your narrowband o2 sensors.

IF and I do mean "IF" you use the keep it in closed loop method - make sure your O2's are correct and not giving you false information - common with headers or air adders changing your airflow calculation tables for the O2's and then make dang sure to pull 10 to 15 degrees out of the spark table AND THEN do like previously stated and design in further safeties such as going into PE still with anything over 80% calculated PE pedal "not to be confused with regular pedal"...

GHuggins; You lost me on much of this part… Sorry, still a newbie… but learning fast (though not as fast as my ’98 SS!)
?Pull 10 to 15 degrees of timing? Not questioning, just trying to understand why, why so much?


Thanks for the input and great guidance.
Mike

[AutoWiz]

Despite what a lot of people here will tell you, your own logic should tell you that the more inputs the ecu has can only translate into the better control over your engine the ecu will have. You should also be able to clearly see that the advantage to electronic fuel injection over the old school carbs is that it can adjust for different conditions trimming it's fuel delivery to a painfully specific accuracy. The best you will ever make your stuff run is with a good ve table and a good maf calibration in closed loop with a switchover at or around 4k. When everything is right there is a certain smoothness to the way the motor runs. And if the maf or map sensor fail you can still drive home. And if your fuel filter starts to get dirty or your vacuum booster starts to leak air and you are in closed loop then no harmful pinging will be heard.

Without a dyno and without a wideband, I think I would dial in the ve table and the maf as best you can as far as you can, then make sure the areas of your ve table and maf you don't get to tune follow a common trend. That is all ve tables are different but in 3d view they are similar. Same with maf curves. So you tune what you can where you can with your fast switching narrowband o2's(LTFT). Then because you are n/a and you do not need to verify dropping down to the low 12's, On WOT pulls you can just make sure that your o2 sensors are pegged in the 900mv+ range. This ensures you are richer than 14:1 and within a single point of your afr target. Less if you like 13.2-13.5 for wot. And so long as you get no kr and you are pegged 900+mv on both your o2 sensors, then you can add 2 degrees of timing to your main spark table in the areas you logged on your pull. If o2's come down below 900mv then goto maf calibration in the hz you logged where the o2 dropped and multiply the value in that cell by 1.02 or 1.05. If you get kr and your o2s are pegged over 900mv then you can try running a higher octane fuel or you can back off 2 or 5 degrees from the point of noise. Just so there is a little headway. It is important to note that one degree of kr is not damaging in the tuning process especially when the ecu is pulling that amount of timing as soon as it sees it. And as long as you walk up your timing in small incriments like 2 degrees at a time, then your kr when you bump up against it will be under 2 degrees.


When it comes to ve table and maf calibrations, you should try to get o2 sensor data from a chart in vcm scanner and copy and paste it or rather paste special multiply by % and then when the numbers in your charts are getting smaller you will copy and paste special multiply by half. This method will let the ve table and maf calibrations build themselves and you will only have to look at them in 3d and 2d chart view for smoothing. There are a lot of helpful short videos on youtube from the tuning school that might be helpful in getting more familiar with vcm scanner and charts. Here is one:

https://www.youtube.com/watch?v=iEBvufxAvqM

[AutoWiz]

Once you have found your upper limit with ignition timing and both of your o2 sensors have stayed pegged over 900mv you can log maf hz and compare it to your o2 on your wot pulls and start picking areas of your wot pull and find those cells in your maf calibration and multiply them by .98 and make another pull always watching for kr. When you see one or both of the o2 sensors come down into the 800mv range then you know you are just getting above 14:1. If you command your pe to 13.8 while you are doing this than you can change your commanded pe when you are done to 12.8 or 13.2 and in theory you will be correct. In reality you will be close.

[GHuggins]

The reason why you pull the timing is so it doesn't have the "ability" to knock - last thing you want is it knocking and cracking a piston or ring land because your trying to cheap out and tune without a wideband installed Being as nice as I can with that statement too

Next thing you can do to make things really easy and quick for you is to also disable ltft's in the tune until your air model is dialed in - this will make things go quickly and keep the occasional PE readings from interfering with your regular fuel trim readings...

I am in absolutely no way indorsing closed loop fuel trim tuning solely - I always tune with both in the picture as it would be normally, BUT if you do - make sure to pull the timing and since this is a gen 3 - make sure both of your timing tables are the same while in SD mode... In other words pull the timing from the high octane table and then copy and paste the entire table into the low octane table... This is all temporary and only until the air model is done...

To clarify on the airflow and O2 subject - everything O2 switching and control related are defined by the amount of airflow the engine is seeing - SD isn't as noticeable, but if you change the air intake tube diameter, O2 location or anything like that - the O2 portion of the tune will be off meaning all of the tuning your doing in closed loop will make your then open loop PE commanded fueling off... Which is just another reason why people don't like using "this" method...

Also don't worry about modifying the VE table by anything until you fail the MAF correctly and re-log...

[AutoWiz]

Time to start draining the swap. Hey GHuggins, how's about some more details on that magnuson heartbeat pushing 20psi on 93 octane fuel? Got any proof to share with us on this build? Or better some more detailed specs like what kind of static compression are you running that you can get to 20psi on pump gas? If I was involved in something like that I sure know I would have a whole mess of proff to offer the masses on what I did. So how's about it?

[Oleblu]

Probably best to bark up trees through pm insted of more cluttering of threads. Which it seems your particularly good at

[AutoWiz]

I'm sorry Oleblu but that's not how you drain a swamp. This dirty laundry needs to be aired out publicly. And GHuggins has some outlandish claims at the bottom of his every post that require some explaining. OK, ok that require A LOT of explaining. We are a magnuson dealer and installer. And I know a few things about that heartbeat blower. And I know a few things about power adders and boost. And most importantly, I want to help all the little guys in here who be like..

[AutoWiz]

A little bit of sanity for you all. If someone were by some miracle able to get a motor to run such low compression so they could safely run 20psi off of 93 octane and were able by an even larger miracle to get over 900hp, the very next step and on that same day for anybody would be to put 110 in it and start ramping up the timing and boast on 4 digit power numbers. But this man's claims just befuddle common logic. So then how long have you been lying to everybody on this forum and yourself GHuggins??