Car feels like it lauched in "drive" or 3rd gear. Is it a tune problem ?
05-01-2008, 09:15 AM
#1
Car feels like it lauched in "drive" or 3rd gear. Is it a tune problem ? 1998 Trans Am
LS1
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 **** 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. (problem occurs more on the street with the tighter converter)
Changed MAF
Check engine, as in 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.
What the hell is wrong ? ECM ? Tuning ?
LS1
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 **** 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. (problem occurs more on the street with the tighter converter)
Changed MAF
Check engine, as in 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.
What the hell is wrong ? ECM ? Tuning ?
05-01-2008, 04:46 PM
#2
I am currently having the same problem, except on a more consistent basis at the track- on the street its fine. I also have a 4000 stall, 4.10's, but with a h/c. All the research ive done points to the tps being messed up. Mine reads .4-.8 at idle and cant get it to go away. You may want to look into that. Good luck.
05-01-2008, 06:57 PM
#3
Here is a good read about my experience with this as well as info gathered over the years http://www.hptuners.com/forum/showthread.php?p=101510
05-05-2008, 11:58 PM
#6
9 Second Club
iTrader: (9)
Join Date: Nov 2007
Location: mississippi
Posts: 220
Likes: 0
Received 0 Likes
on
0 Posts
What if you just changed to a th350 and the first 4 or 5 runs it done great and then you stall up at the line and when you leave it just bogs down untill about the 60ft mark and then takes off like i shot it with nitrous.........I will not even do a burn out now.......
