car is a 2004 gto. ls1 with 228r cam. headers. no cats. stock heads/intake/tb. working on getting a log but this is the tune that was in the car when i bought it. on decel when you push the clutch in, rpms drop way down then it intermittently dies. this is worse with the ac on. if you're cruising on the throttle and quick let off and push the clutch in it doesnt happen. does anything stick out here? will post log as soon as i can. gto-1.hpt
do you have a log of this happening by chance?
updating vcm suite then ill go out and get a log
going to send you a DM
You might try raising your stall saver setting on the lower RPM range and try raising your timing in the Deceleration cells that youre hitting when you clutch. watch your log and get a good idea of what area this is happening in then raise it by a couple degrees. make sure to smooth the edges of the area you adjust so theres not a big jump from one cell to another. remember the smoother the tranistion the better itll perform. Same with VE and MAF and pretty much anything else....
Im at work til monday so i cant view your log or tune until then. maybe someone else will chime in with advice by then.
log attached. started from cold. drove around showing differences between ac on and off.6-25-23 gto log.hpl
I notice you have your adaptive idles off along with rolling idle/throttle cracker off. Any reason behind that?
This is what came in the car. Guessing that?s not helping my issue?
I would figure out why it is going so lean on deceleration, and for some reason-only on bank 1? When I play the log it looks like only B1 is going super lean... bank 2 appears normal. There may be something happening with B1S1 O2 sensor that is causing the issue, or an exhaust leak on bank 1, or an injector that is not working, or a coil that is intermittently misfiring. There is a discrepancy between the two banks in the log. I'm willing to bet that if you can figure out what that discrepancy is, and fix it, that you will be in a much better place.
I will take a look. Thanks for the input!
fixed my exhaust leak on left bank. reset fuel trims. drove around. still seems to be doing it but decel/coming to idle ltft looks better. any suggestions? 6-28-log.hpl
Sent you a dm
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so the bank to bank fuel trims look much better... Why does your TPS/APP ALWAYS show 0? That seems odd.
I would go in and reduce the OVERSPEED idle spark. You can see that every time you let off the gas the PCM immediately begins pulling a bunch of timing, and that happens right before the engine stalls. Watching your timing advance, you are going into negative #'s on deceleration causing a rapid engine rpm decline that the PCM cannot catch before stalling. Also, just looking at STFT you can see that it's going very lean on deceleration. That lean condition and NEGATIVE spark is contributing to the engine stalling. Did you re-enable the Idle adaptives?
On your scanner log-get rid of all of the Misfire channels, A/C channels, CRUISE channels, and anything else that does not relate to engine airflow. Get TPS/APP working. Log MAF FREQUENCY as well. Not to nit-pick, but put your timing advance, right next to your idle advance in your channels list so that you can see how the PCM is affecting timing on deceleration.
It is doing what it should. Cable driven throttle.Originally Posted by HATEHPTUNERS
Timing crashing is where you need to look.
Yes, if he is DBC, than he needs to be logging TPS % as well.
Chumba-is there a fast and easy way to look at the tune and identify whether it is DBC, or DBW? I'm sure there is a simple way, I've just never known it. I would have assumed that he was DBW because most F-bodies in those years were DBW....
and... as a test.. he can go into his scanner under controls and lock his timing at something like 18 degrees, during a log session, and then see if the engine is able to maintain idle under those circumstances.
Last edited by HATEHPTUNERS; 06-29-2023 at 06:30 AM.
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