lean area around 2500ish rpms-2014 ctsv

[JayRolla]

Interesting that you notice it then. I was dyno tuning that particular car at 3400ft when I noticed it's "issue". Again it was only on E and I'm not even sure it was the same issue. It just had a lean tip in while at cruise speed and moving the pedal down more. It was also pullied with headers, a cai and 850's. Those were it's only mods if I'm even remembering it right. Only remembered it because you mentioned running E as it was 6 years ago since I tuned it Again, all of this may not make a bit of difference...

Slapped your tune in. Nothing changed for the spike but the additional timing down low does feel better. Im at 6k altitude for what it matters.

[pannetron]

Could that lean spike be a misfire?

[blindsquirrel]

All these different cars with different mods all having the exact same glitch at the exact same RPM?

[JayRolla]

All these different cars with different mods all having the exact same glitch at the exact same RPM?

Yes. Right at 2600rpms. I go from 1.00ish to 1.12ish for about 100rpms and then richens right back up. It also does it at WOT in PE. Goes from .79 to .85 and then back to rich again. Tossing fuel at it with VVE or PE table does not really help much at all. Its usually at around 30-40% throttle. If say 5-20%ish throttle it does not seem to happen or not as bad. Seems to happen ever since I upgraded the injectors. I am going to look through some old logs before I changed the injectors and then right after to make sure.

[JayRolla]

Could that lean spike be a misfire?

I dont think so. Usually a misfire if from no spark it would cause it to richen not lean out. Unless the misfire is from an injector not firing. But seems that would be strange that all our cars are having the exact same misfire at the exact same RPM. Wonder how I could try to diagnose if its a misfire or not with a log? It also does seem it started right after installing the larger injectors.

[JayRolla]

https://www.ctsvowners.com/threads/o...tumble.143730/

I found this thread with someone that seemed to have the same issue with a manual 6 speed car. They said the tuner fixed it by correcting the injector scaling. Right now I have my IFR at 50% of injector size and then doubled the stoich table to scale my injectors. I remember when I first installed my injectors I didnt scale them and maxed out the upper tables just to get it running. I dont know if I had the stumble then. Then I scaled them and maybe thats when the issues started. I need to look at some older logs but maybe this issue has to do with the scaling somehow.

[blindsquirrel]

Double stoich and half IFR... and also half IVT Terms>AFR Term (I think it's ECM 12560)?

[JayRolla]

Double stoich and half IFR... and also half IVT Terms>AFR Term (I think it's ECM 12560)?

Just read about the IVT table. I dont think I have done this. I will do that tonight and see if it helps. Does seem a lot of users said it made the car feel smoother from a stop or low rpm throttle. Thanks for the tip!

[sgod1100]

Just read about the IVT table. I dont think I have done this. I will do that tonight and see if it helps. Does seem a lot of users said it made the car feel smoother from a stop or low rpm throttle. Thanks for the tip!

pretty sure that's not going to help...besides with ID1050s (like the 850s I had) you don't need to do any scaling

[sgod1100]

All these different cars with different mods all having the exact same glitch at the exact same RPM?

that's why I wonder if the prediction coefficients may need to be tweaked?? To add fuel at that particular VVE zone? I'm just guessing here by the way

[sgod1100]

Did any of you guys change the "make up pulse min" in the injection timing tab? When I had my 850s in I had that table the same as "min injector pulse". Not sure if this would help with the lean issue, but just a side question. I've seen some tunes with aftermarket injectors that the "make up pulse min" is still stock

[JayRolla]

pretty sure that's not going to help...besides with ID1050s (like the 850s I had) you don't need to do any scaling

I thought so also but the data you input from injector dymanics goes over the 127lb maximum or am I missing something? I didnt scale them when I 1st installed and it seemed to run fine but I was being OCD to get the correct data in the tables I guess. Here is the data from the 1050cc's

64.04 68.92 73.65 78.23 82.66 86.93 91.05 95.02 98.83 102.50 106.01 109.37 112.58 115.63 118.53 121.26 123.833 126.270 128.587 130.778 132.762 134.595 136.381 138.214 140.175 142.206 144.278 146.389 148.532 150.722 152.960 155.230 157.540

[JayRolla]

Did any of you guys change the "make up pulse min" in the injection timing tab? When I had my 850s in I had that table the same as "min injector pulse". Not sure if this would help with the lean issue, but just a side question. I've seen some tunes with aftermarket injectors that the "make up pulse min" is still stock

Mine is still stock. I didnt see that needing to be changed from any of the data from ID or tutorials I found for injector change.

[GHuggins]

Found another one I had done for the lsa blower and 1050's that didn't have this problem - at least to my knowledge. I put all of the tables into Jay's. You'll probably have to retune the MAF or just plug it in and let the o2's correct for the quick drive... It's got to be something in the calcs that the ecm is seeing and testing for.

[JayRolla]

Found another one I had done for the lsa blower and 1050's that didn't have this problem - at least to my knowledge. I put all of the tables into Ray's. You'll probably have to retune the MAF or just plug it in and let the o2's correct for the quick drive... It's got to be something in the calcs that the ecm is seeing and testing for.

Okay thanks, I will try this out tonight.

[sgod1100]

Mine is still stock. I didnt see that needing to be changed from any of the data from ID or tutorials I found for injector change.

ok, thanks for letting me know. I'll make sure to keep mine stock as well

[sgod1100]

Found another one I had done for the lsa blower and 1050's that didn't have this problem - at least to my knowledge. I put all of the tables into Jay's. You'll probably have to retune the MAF or just plug it in and let the o2's correct for the quick drive... It's got to be something in the calcs that the ecm is seeing and testing for.

I noticed that your "makeup pulse min" matches your "min injector pulse" in this tune. Was there a particular reason for that? I also notice you VVE having a rather large spike right at the 2500-2600ish rpms. That to me indicates the car had the same problem we are having

[blindsquirrel]

I thought so also but the data you input from injector dymanics goes over the 127lb maximum or am I missing something? I didnt scale them when I 1st installed and it seemed to run fine but I was being OCD to get the correct data in the tables I guess. Here is the data from the 1050cc's

64.04 68.92 73.65 78.23 82.66 86.93 91.05 95.02 98.83 102.50 106.01 109.37 112.58 115.63 118.53 121.26 123.833 126.270 128.587 130.778 132.762 134.595 136.381 138.214 140.175 142.206 144.278 146.389 148.532 150.722 152.960 155.230 157.540

Technically it only needs data in the cells it's actually capable of hitting. The ones to the right of 480/488 would need either impossibly high vacuum (low MAP) or more than 58psi rail pressure with MAP very low.

The first E38s to use the 128-640 axis scaling had placeholder data to the left of 400kPa & to the right of 480kPa, because with fixed 58psi in the rail and a N/A engine it just can't get outside that range unless something's broke.

[JayRolla]

I noticed that your "makeup pulse min" matches your "min injector pulse" in this tune. Was there a particular reason for that? I also notice you VVE having a rather large spike right at the 2500-2600ish rpms. That to me indicates the car had the same problem we are having

I bet that VVE spike is just from my tune. And that was created by doing EQ error from the wbo2. So that is the wbo2 error being seen and trying to correct the issue. I bet if I tuned via LTFT it would not have as much of a spike. Pretty sure he just changed the injector data. You can download my original tune to compare.

[JayRolla]

Technically it only needs data in the cells it's actually capable of hitting. The ones to the right of 480/488 would need either impossibly high vacuum (low MAP) or more than 58psi rail pressure with MAP very low.

The first E38s to use the 128-640 axis scaling had placeholder data to the left of 400kPa & to the right of 480kPa, because with fixed 58psi in the rail and a N/A engine it just can't get outside that range unless something's broke.

That sounds right. I am going to toss in the tune that Ghuggins posted for me without injector scaling.