I'm looking for some possible ideas on my problem child of a car.
Sorry for the long post...
2004 Cobra
DSS built motor, Roush heads, Comp Cams etc...
3.4 Whipple @26psi
4R70W Auto
The car was tuned a few months ago and made 660whp with belt slip on 19psi. Unlocked converter.
I put a Thump tensioner in, made one more dyno pull and updated the tune on May 7th. 732whp on 26psi or so.
It ran great.
I added a drive shaft loop, drove the car 1 time in town without issue, and then went to the track about 4 weeks ago.
I noticed it was really rich and wasn't running as fast as it should, so I only made three passes.
It still ran 6.50s in the 1/8, but it should be significantly faster.
Whatever happened is slowly getting worse.
Now under light throttle the widebands will peg out rich and the car will stumble like crazy. It sounds almost like launch control.
(I have 1 wideband on each header. Both are going rich)
I can't get it to act up in park/neutral.
Usually happens around 2500 rpm or so, but not always.
You can give it more gas and it will come out of it, but it is still breaking up under heavier throttle.
You can actually watch the widebands sit in the 12-14 range as you push on the gas... then randomly they will start to head down and the car will start to stumble.
It starts and idles fine without touching the gas. With the big cams, its hard to hear a miss or something at idle.
So far I have tried:
New plugs - BR7EF gapped at .022
Swapped Coils
New cam/crank sensor
New O2 sensors
New BA5000 MAF
Reflashed the tune
Smoked the car for vacuum leaks
New alternator - previous voltage drop issue
Watched throttle position sensor on scanner - sweep was clean and steady
I'm waiting for my handheld to get the PATS unlocked so I can try another PCM.
Data logs haven't shown anything useful to me.
No check engine lights or codes.
I really thought it was the MAF, but I got a new one today with no luck.
Any thoughts or suggestions?
I might have to go back to the tuner and see what we can see.
Its getting worse, so I guess I'm hoping something will just fail completely and I can figure it out easier.
Here's a short video of how its acting. This is just slowly easing into the throttle.
https://youtu.be/7Z8dMVMDkg0
Dyno Video just because:
https://youtu.be/r2D84WT3S7A
TIA
Sorry for the long post...
2004 Cobra
DSS built motor, Roush heads, Comp Cams etc...
3.4 Whipple @26psi
4R70W Auto
The car was tuned a few months ago and made 660whp with belt slip on 19psi. Unlocked converter.
I put a Thump tensioner in, made one more dyno pull and updated the tune on May 7th. 732whp on 26psi or so.
It ran great.
I added a drive shaft loop, drove the car 1 time in town without issue, and then went to the track about 4 weeks ago.
I noticed it was really rich and wasn't running as fast as it should, so I only made three passes.
It still ran 6.50s in the 1/8, but it should be significantly faster.
Whatever happened is slowly getting worse.
Now under light throttle the widebands will peg out rich and the car will stumble like crazy. It sounds almost like launch control.
(I have 1 wideband on each header. Both are going rich)
I can't get it to act up in park/neutral.
Usually happens around 2500 rpm or so, but not always.
You can give it more gas and it will come out of it, but it is still breaking up under heavier throttle.
You can actually watch the widebands sit in the 12-14 range as you push on the gas... then randomly they will start to head down and the car will start to stumble.
It starts and idles fine without touching the gas. With the big cams, its hard to hear a miss or something at idle.
So far I have tried:
New plugs - BR7EF gapped at .022
Swapped Coils
New cam/crank sensor
New O2 sensors
New BA5000 MAF
Reflashed the tune
Smoked the car for vacuum leaks
New alternator - previous voltage drop issue
Watched throttle position sensor on scanner - sweep was clean and steady
I'm waiting for my handheld to get the PATS unlocked so I can try another PCM.
Data logs haven't shown anything useful to me.
No check engine lights or codes.
I really thought it was the MAF, but I got a new one today with no luck.
Any thoughts or suggestions?
I might have to go back to the tuner and see what we can see.
Its getting worse, so I guess I'm hoping something will just fail completely and I can figure it out easier.
Here's a short video of how its acting. This is just slowly easing into the throttle.
https://youtu.be/7Z8dMVMDkg0
Dyno Video just because:
https://youtu.be/r2D84WT3S7A
TIA
