[99saleensheep]

Hello. This is my first post so I figured I'd make it a good one. Here's the problem. My car dies at idle after it gets hot. Easy enough.
I've done multiple swaps but haven't encountered this.
Car is a 1999 GT 4.6 that I swapped a 2001 Bullitt into. GT wiring harness and computer. I've replaced MAF, TPS, CKP, CMP, egr valve, dpfe sensor, egr vacuum regulator, fuel rail pressure sensor, IAC, ECT, fuel injectors, coil on plugs, spark plugs, oxygen sensors (4), fuel pump, fuel filter. Engine was resealed and rebuilt. New head rebuilt using Comp Cams valve springs, retainers, valve seals, and XE272 cams.
At cold idle car is fine, runs great. After it warms up it dies at idle unless I give it gas.
Compression check was all good, no blow by. Cylinder leak down test passed, no issues. Smoke check revealed no leaks. No vacuum or exhaust leaks. Fuel pressure was normal at cold and idle. Timing was set correctly.
So, any ideas as to my problem? I was thinking ECU was the issue and I'd have to flash it and put Bullitt tune on.
I appreciate any and all help. Thank you.


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[Ezekial]

My guess is with the cams and intake, you need a tune to account for the significant differences from a stock GT.
With so many sensors replaced, that seems to me the most likely candidate at this point. If you want to double check sensors, I think the IAC would be the most likely sensor to cause this issue.

 

[99saleensheep]

Thanks for the input. The IAC was my first guess too. I double checked it. Electrically and mechanically it works as it's supposed to. The computer is where I end up every time.

 

[sganow]

I would think it needs to be tuned, especially since you have aftermarket cams.

 

[hondamoto17]

Hello. This is my first post so I figured I'd make it a good one. Here's the problem. My car dies at idle after it gets hot. Easy enough. I've done multiple swaps but haven't encountered this. Car is a 1999 GT 4.6 that I swapped a 2001 Bullitt into. GT wiring harness and computer. I've replaced MAF, TPS, CKP, CMP, egr valve, dpfe sensor, egr vacuum regulator, fuel rail pressure sensor, IAC, ECT, fuel injectors, coil on plugs, spark plugs, oxygen sensors (4), fuel pump, fuel filter. Engine was resealed and rebuilt. New head rebuilt using Comp Cams valve springs, retainers, valve seals, and XE272 cams. At cold idle car is fine, runs great. After it warms up it dies at idle unless I give it gas. Compression check was all good, no blow by. Cylinder leak down test passed, no issues. Smoke check revealed no leaks. No vacuum or exhaust leaks. Fuel pressure was normal at cold and idle. Timing was set correctly. So, any ideas as to my problem? I was thinking ECU was the issue and I'd have to flash it and put Bullitt tune on. I appreciate any and all help. Thank you. === This is an automatically generated message === This is my first post. My Welcome thread is here. Please post all my welcome message there. === This is an automatically generated message ===

I’m also in the middle of a swap 2002 gt with 2001 bullitt drivetrain, you did use gt harness and computer right? Or is there an adapter to make bullitt harness fit all plugs inside the cab? Thank you!