GEN 5 Camaro goes lean after 5-10 minutes. Immediately fixed after re-flashing ECM.

[c.u]

Dave is this a purging disorder.

[Pekka_Perkeles]

Dave is this a purging disorder.

He is god.

From the business perspective, do we really want this (HP Tuners) to be a single tuner platform?

I've not seen too much responses lately for threads started by junior tuners. Just a coincidence perhaps.

Anyway, it is good there's at least one person who is able to tune these PCM's as intended. I wish I would be able to do the same someday.

[NYLS1346]

Well i was about to start a thread because im pulling my hair out on a 2011 camaro ss w/ a procharger i tuned. i tuned it on my mustang dyno and everythings within 3% then the customer picked it up and its getting lean conditiin codes and then im adding 30% fuel on the street.. so i tried tuning it on the dyno again to go over everything and the same thing.. i really hope this is whats going on because its not making any sense, however i noticed when im on the street and i flash the corrected tune in and go on to do another log and its still adding fuel

[c.u]

He is god.

From the business perspective, do we really want this (HP Tuners) to be a single tuner platform?

I've not seen too much responses lately for threads started by junior tuners. Just a coincidence perhaps.

Anyway, it is good there's at least one person who is able to tune these PCM's as intended. I wish I would be able to do the same someday.

I was playing on words. What he posted log fuel trim cell,So i would look to EVAP purge or DI. If you do a search on EVAP purge go to page three some good info there. But it looks like you Know about this already.

[DSteck]

If you run the fizuckwitz out of it after you reflash it, it clears up very quick.

[Pekka_Perkeles]

I was playing on words. What he posted log fuel trim cell,So i would look to EVAP purge or DI.

Sorry, I'm not native in English. I just didn't catch it.

If you do a search on EVAP purge go to page three some good info there. But it looks like you Know about this already.

I will definitely search that right after this message.

And no, I was not aware there may be up to 10 minute period to have rich AFR after flashig because of EVAP.

Anyway, with my rather problematic online attitude and low amount of contacts with fellow tuners here in Europe, I will never catch the pro's in United States. So be it. But what I will try to do in future is to help some new members in this forum, at least from time to time.

[LSxpwrdZ]

Chris, Bill can we have EVAP parameters added to the Gen4 apps so that we can manipulate these affects. Makes everything timing consuming trying to dial in a car and having to wait. I normally unplug the EVAP solenoid just so it physically cannot cause issues with tuning but I still see ~10% rich for the first 8-10mins.

[Midnite Magic]

If you run the fizuckwitz out of it after you reflash it, it clears up very quick.

True all you need is a quick WOT pull on the dyno and everything is back to normal

[mustangtuner77]

I have a 2005 gto im dealing with same exact thing been a week into this thing after reflash pig rich then goes lean ive changed more stuff than needed that for sure so started back over with a stock tune and been doing what midnight said slap it up to a small wot and boom back to lambda 1 its insane after a reflash!

[openwheel25]

I have been having the same problem. It will go very rich after a flash and by the end of a drive it will be very lean. So, if going WOT makes it go to normal how do you tune it. Meaning make a change then flash the car, start it up and put it on the floor for a few seconds? Or does it have to be under a load when it is WOT? I wonder if this is a computer glitch and bigger injectors make it worse. This is a interesting thread I have been fighting this for some time.

[Moparmatty]

I am dealing with the same thing right now.

[edge04]

So does this still need to be done or does it need to driven for 10 mins first even if you are running in OL and reset the trims? Based on the speculation on why this happens I am guessing yes.

[LSxpwrdZ]

I know it is def not EVAP related. I unplugged the EVAP solenoid and blocked it off on several cars now and no change. There is some background pulse modifier that is causing this issue. Haven't had much spare time to experiment anymore but really curious to find what is causing the issue.

[openwheel25]

I agree with LSxpwrdz. I too have unplugged the evap and also logged the evap purge on the scanner. Even when the evap has been commanded closed the car is still rich. I think that there is a pulse modifier just like LSxpwrdz said because the PW of the injector in the scanner is the same when it is running rich as when it is running lean. This problem has really drove me batty until I realized what was going on. I even changed the ecm thinking it was corrupted.

[MikeOD]

I agree with LSxpwrdz. I too have unplugged the evap and also logged the evap purge on the scanner. Even when the evap has been commanded closed the car is still rich. I think that there is a pulse modifier just like LSxpwrdz said because the PW of the injector in the scanner is the same when it is running rich as when it is running lean. This problem has really drove me batty until I realized what was going on. I even changed the ecm thinking it was corrupted.

I agree that it's gotta be a short pulse modifier. The commanded fuel is correct, and you're right, the theoretical pulsewidth (which is what the E38 shows us) isn't changed, but based on the data from the wideband, the ACTUAL pulsewidth absolutely is modified, and since the scanner can't show us that, we can't tune correctly until it clears up.

I've been going as far as to drive for over a half hour now before I log VE/MAF errors...and it still really isn't right.

[openwheel25]

What I have been doing is after a flash I let the car sit with the ignition off for a few hours. It also seems if it has been held under a load for some time it will go back to normal. Like if you go up a long step hill. But, the AFR for me to so rich I don't like to drive it for very long so I let it sit.

[Mike@G-Force]

Still no fix!!!

[Pekka_Perkeles]

Any updates?

[IDRIVEAG8GT]

Post O2 testing in the diagnostics section if left enabled can make a radical difference with post startup fueling.

[MikeOD]

Post O2 testing in the diagnostics section if left enabled can make a radical difference with post startup fueling.

It's disabled in the stock 2010 Camaro LS3 calibration.