Oil_Money

I recently replace my 5.0L with a 347 stroker in my 1991 GT. The engine description from the builder is:

Stock block, 0.030 over, SRP Pistons, Scat Rods and Crank
about 9.5:1 compression, balanced,SFI Damper

Patriot Aluminum 185cc heads with a little port work, Roller rockers, 280 HR comp Cam, TFS Track Heat Intake, 24# Injectors, 70mm BBK Throttle body.

The engine was installed, including long tube headers, and was running great! However, the car was then taken to a different shop to have a strut tower brace, intake tube and exhaust installed, as well as a wheel alignment. While at this shop they welded on the intake tube and the exhaust pipe due to the headers.

We then got the car back with all of this installed and it runs like absolute crap now. At idle it is not too bad, but when taken to 2-3000 rpm it starts sputtering and popping and the tac bounces when this misfiring is happening.

They have replaced the plugs, wires, cap, rotor, distributor, MAF, we have even tryed a new (not 100% new but from a different car) PCM.

I have an engine wiring harness and a rebuilt PCM on order with fingers crossed it will cause this gremlin to go away.

If anyone has any comments/ideas I would appreciate it.

Thanks

1989 GT KY

Did they disconnect the battery when they did the welding? That could be your problem.

89StangGTConvertible

Electrical problems can be a real PITA. Hopefully someone on the forum can help so you can you get it sorted out - sounds like you have a sweet little setup with that stoker motor.

Oil_Money

Thanks for the responses.

We are doubting they disconnected the battery when welding. That seems to be accepted at the culprit, but trying to find what got fried from that is frustrating (and expensive).

I dont know what else to try before we take it to some electrical "specialist".

1989 GT KY

Have you tried to speak with the shop that did the work? It seems they should have some level of owership for this issue!

Oil_Money

Well the problem is there are two shops involved, the engine and muffler shop. Each is pointing the finger at the other saying that it isn't anything that they did to cause this.

1989 GT KY

Oh, the plot thickens. You would be suprised what a call from a lawyer can do. I would get an estimate from an indy shop and go from there. Keep track of all your reciepts. I'm not one to play the sue card, but in this case I think I would persue it. Don't cost anything to try.. Good luck, I hope you get it resolved.

Bubba 95SN

Test the EEC 1V system? Fuel pressure?

1989 GT KY

Any welding shop worth their salt would know to break ANY ground prior to welding ANYTHING. I'm a garage builder and know better,