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Tuner in Training
Car feels like it is lauching in 3rd gear. PLEASE HELP !!
1998 Trans Am
4000 stall converter
Cam
4.10 gear
Saturday I made 1/4 mile 10 passes with the car, no problems. On Sunday I made 3 passes and then on the fourth pass when I lauched the car the motor started lugging. It felt like the car left the starting line in 3rd gear. If I manually down shift the car down to 2nd or 1st the car will wake back up and run correctly. I am still having this problem. If I manually shift the car at the track it runs fine. What I don't understand is that the car made 13 clean runs and then I had the problem. I didn't change the tune at all during the runs.
On the street it will drive fine when you drive it normally. When you beat the shit out of the car the problem comes up intermitently. Sometimes on the street I can go WOT and the trans will stay in OD or D while only going 30 mph.
Things I tried to fix/troubleshoot the problem:
Changed converters 4000 stall to a 3000 stall.
Changed MAF
Check engine, as is fuel pressure, and compression check.
Brought the trans back to the builder, had them go thru it and dyno test it. They could not re-create the problem on their trans dyno shifting it electronically.
I am not getting any DTC's.
Is this a trans problem ? ECM ? Tuning ?
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Tuner in Training
I attatched some logs and my tune.
"Bad Pass at US41" is the first time I had the problem, 2 weeks ago. Unfortuneatly I was not logging any good trans info.
"Good Pass at US41" is the pass I made right before I started having the problem. Unfortuneatly I was not logging any good trans info.
"4-26-08 same problem manually shifted" is from this past saturday after the trans was gone thru, a different converter, and I manually downshifted the trans during the run when I had the problem. I was logging trans input and output rpm, and PCS current.
"Streetdriving" this is a log of me driving the car to work and getting the car to have the problem several times on the street. I was logging trans input and output rpm, and PCS current.
time frames or points of interest:
1140-1160 The trans stayed in overdrive at WOT
1680-1760 I manually downshifted into second to get the car to wake up
2240-2300 In OD @ WOT again
3020-3100 Drove the car nice, leaving a stop light.
3140-3160 In OD @ WOT again
4140-4160 In 3rd gear @ WOT
4240-4320 I manually shifted the car
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Tuner in Training
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Tuner in Training
Common, nobody knows anything about this problem ???
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Tuner in Training
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Advanced Tuner
we had this problem once inn 99 C5 Vet A4 and if I remember correctly it was a range adjustment on trans to tell ECU what gear car was in.
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Tuner in Training
UpDate !!
This was the problem.
http://www.hptuners.com/forum/showthread.php?p=101510
I disabled the TPS error test as per the above thread.