One thing that I've done to help a little bit is slow down the switching of the O2 sensorsOriginally Posted by JayRolla
One thing that I've done to help a little bit is slow down the switching of the O2 sensors
Yeah, the DC seemed to be locked at 60% without changing the base setting. Sorry this log is very short as I just drove around the block to test this
fuel pump DC locked at 60%.hpl
Are you sure it's not misfiring here? Played with adding and pulling some timing? I see pressure drop a touch, but not like it was unless I'm remembering wrong? Pressure always stays above commanded and wondering if something else is going on as it's still the exact same amount lean. You would think with the added pressure that it would change something. It also seems to be gear or load dependent. Didn't do it at all with the first accel, but there plain as day the next gear. Maybe it's just revving slower and more obvious at that point?
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
No I don't think it's misfiring. Yeah, seems the more load on the engine is when it tends to do it more. Not gear dependent as it will do it in any gear..I just feel it much more in the lower gears obviously. Played with timing long ago and that didn't do anything either unfortunately.
So I encountered something like this on a 2012 ZL1 I did recently. Was quite a bit worse, so the root cause was a bit more apparent. But could be what's happening here...
337256957_3447472042182291_5657708164859947558_n.jpg
Log on the left is before with an intake tube that didn't get along with the car. On the right is a smaller diameter/length tube with the MAF sensor blanket-scaled for good measure. Literally no other changes. Higher sample rate data shows an invasive noise that permeates basically everything in the powertrain. The setup clearly suffered from MAF reversion, but the amplitude of the MAF signal was large enough that it dynamically coupled with the fuel system through the ECM's injection control. Spikes in the airflow drove fuel demand way up, which put excess load on the fuel supply and caused fuel pressure to fluctuate wildly as well and continue the cycle. The noisy fuel delivery showed up as leanness on the wideband due to the FP and injector pulsewidth drops despite flowing a bunch of fuel.
The trick to spotting it is high rate data. You may have to get rid of a bunch of channels, but try to isolate the airflows, fuel pressure/inj pw, cylinder airmass and MAF frequency. In the 'fuel pump DC locked at 60%' file, the wideband does show some real sharp noise in the trace right as fuel pressure starts to dance. Airflows are updated too slow to judge though. Strip out a lot of the parameters and max out the polling on those few airflow/fuel channels and see how it responds. Wouldn't be surprised to see some sawtooth waveforms show up in the MAF and whatnot.
Yeah, thanks for the suggestion on doing this. I'll be trying this as soon as I can. Is the "correct way" at getting high rate data by deleting as many PIDs as you can and then verify the polling rate for the remaining PIDs is as fast as it can be?
You know it is funny that you found this, because honestly I thought about changing the axis of the MAF and testing this same theory. I just found it very odd that it was present in MAF, VE and rpm dependent which is why I never did. It also didn't make sense to me why it was doing it with just an injector change only. Hopefully this is all it is. Something simple that can be fixed in MAF scaling.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Can you enlighten me yet again? How would scaling the maf correct the issue?
What he's saying is he put the MAF in a smaller intake tube forcing it to better read the airflow coming into the engine. As I understood it he also changed the axis of the MAF table to a better resolution to get rid of the spike areas. These spike areas were inevitably causing his fuel pump to loose control, causing pressure to dance and showing up as a lean area on the wideband.
This is if I understood it correctly - if not Smoke can correct me
Basically this - https://www.youtube.com/watch?v=ccF7pv1B-Xg&t=1s
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Gotcha. Yeah, I actually used that maf assistant before. Pretty slick stuff created by Cringer. Just weird that guys with my same exact intake aren't experiencing it...unless they are and don't realize itWhat he's saying is he put the MAF in a smaller intake tube forcing it to better read the airflow coming into the engine. As I understood it he also changed the axis of the MAF table to a better resolution to get rid of the spike areas. These spike areas were inevitably causing his fuel pump to loose control, causing pressure to dance and showing up as a lean area on the wideband.
This is if I understood it correctly - if not Smoke can correct me
Basically this - https://www.youtube.com/watch?v=ccF7pv1B-Xg&t=1s
Last edited by sgod1100; 06-21-2023 at 02:12 PM.
Yes Cringer discusses it quite thoroughly in that vid. The same thing quite often is done to Ford MAFs when converting them to boost or even earlier lt4's as there isn't enough resolution in the idle and cruise areas. Still don't know if this would correct for an injector swap, but I guess it's possible... Awesome if it does.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
No I didn't change the axis in the MAF table. Just multiplied the whole cal by the ratio of the new tube diameter to the old one. Crude, blanket scaler to make the car start back up.
To clarify, it is not a 'bad intake' problem. Several pieces of hardware are involved to create that response. On a different application, the result could be lessened or gone entirely.
Would that still cause it to be rpm and different injector dependent Smoke? I know personally I've never seen one do this before, but obviously the problem exist...
I also assume changing the axis to a finer resolution would be the best way to go about it in this case?
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
Try to take a ZL1 tune and copy over the VE Reversion & Dynamic Airflow gain tables. I did that and made some changes to my intake volume and transient tables and today I did not feel the stumble. Remember I have an automatic. But it use to do it in manual TUTD mode and slightly in normal drive mode and today it was gone.
2013 OBM A6 CTS-V Coupe
Mods: Headers back Billy Boat Exhaust, GripTec 2.65, 8.6 PowerBond Lower, LSX Innovations Solid Isolator, ID850's, NGK TR7IX's, Accel 9070CK Wires, Spectre CAI, SRI Ported Throttle Body, SRI Catch Can, NGK AFRM, 160* T-Stat, 0fx2gv Brick, Hard Line Delete W/3/4" Lines, FB 101 FMIC, Pierberg CWA50, Stoptech Drilled/Slotted Rotors, EBC Redstuff, Cut Stock Springs, Flat Bottom Steering Wheel
2006 Black Raven STS-V (Traded In)
Fully Modded: 459RWHP@5888rpm/451lbft@4696rpm
It's not a matter of resolution. Capturing CAN data on a 10ms raster shows you plenty of detail. It's the matter of requesting constant torque and the system not being able to deliver because of how the hardware/software all interacts. The best approach for a solution is disturbing the interaction. For the ZL1 it was changing the intake.
I meant changing the MAF axis for better resolution and dial in instead of the poling interval, but that's OK. So basically in the case of reversion changing to a smaller diameter pipe for more vacuum to be applied to or rather having quicker flowing air in the intake tube resulting in a cleaner MAF signal might also work in the above cases by shifting or rather smoothing out possible turbulence from taking place that is being caused by the blower pulley swap. Would this take care of it on the VE side as well though? It would theoretically make airflow into the manifold/blower smoother, but would also choke it off a little up top. Better to drive smooth and lose a little if it fixed it.
Hoping the transient and reversion changes takes care of all of them.
2010 Vette Stock Bottom LS3 - LS2 APS Twin Turbo Kit, Trick Flow Heads and Custom Cam - 12psi - 714rwhp and 820rwtq / 100hp Nitrous Shot starting at 3000 rpms - 948rwhp and 1044rwtq still on 93
2011 Vette Cam Only Internal Mod in stock LS3 -- YSI @ 18psi - 811rwhp on 93 / 926rwhp on E60 & 1008rwhp with a 50 shot of nitrous all through a 6L80
~Greg Huggins~
Remote Tuning Available at gh[email protected]
Mobile Tuning Available for North Georgia and WNC
So I found a log when I 1st installed my WBO2 with stock injectors and still had this issue. So I do not believe the injectors are the issue. I also agree that its not the MAF because I can completely fail it and nothing changes.
2013 CTS-V Coupe M6 - 1 7/8" Headers, 3" x-pipe, stock mufflers, Airaid intake w/green filter, ID1050X injectors, DSXtuning flex fuel kit, DMS under hood tank, upgraded pump, 3/4" lines, griptec 2.4" pulley, solid isolator, 100mm idler, reinforced brick, MM mild catch can, AEM 30-0334 wbo2, 600whp/630wtq
Are you also monitoring this area with a wbo2? I sometimes dont get a stumble but stiill see the lean spike. I flashed an entire zl1 tune over that ghuggins did for me and no change but not sure if he kept the zlq ve reversion and dynamic airflow gain tables. I might try this tonight and see what happens.
2013 CTS-V Coupe M6 - 1 7/8" Headers, 3" x-pipe, stock mufflers, Airaid intake w/green filter, ID1050X injectors, DSXtuning flex fuel kit, DMS under hood tank, upgraded pump, 3/4" lines, griptec 2.4" pulley, solid isolator, 100mm idler, reinforced brick, MM mild catch can, AEM 30-0334 wbo2, 600whp/630wtq
did you have anything else done to the car other than installing the WB?
Yeah, I'm going to try it out...nothing to lose at this point..lol. A true test would be to go on the highway in 6th gear and go through that 2600 rpm area to see if you see a "hill" of the WB going lean because I can see that on mine when I do that
Last edited by sgod1100; 06-22-2023 at 09:26 AM.
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