What can it be? Sooo close!

[karmasupra]

Here's the deal, I got a 1j AT supra swap into my 89 AT. The problem is it will not run right with the original ecu. It will crank but when you move the ecu around it starts stumbling, running rough then cuts off. All plugs have a tight fit. I bought another auto ecu and it doesn't even crank but here's the crazy part; put a manual ecu in to try and it runs dam near perfect. The only thing we can think to do is go back and check the engine harness auto trans wires. 3 ecus and the one that not made for my swap works. Any ideas?

 

[mattjk]

I would always recommend replacing all the caps in the ECU first.

 

[OneJSupra]

Here's the deal, I got a 1j AT supra swap into my 89 AT. The problem is it will not run right with the original ecu. It will crank but when you move the ecu around it starts stumbling, running rough then cuts off. All plugs have a tight fit. I bought another auto ecu and it doesn't even crank but here's the crazy part; put a manual ecu in to try and it runs dam near perfect. The only thing we can think to do is go back and check the engine harness auto trans wires. 3 ecus and the one that not made for my swap works. Any ideas?

Call Dr Tweak www.phoenixtuning.com. He's in SAV, GA and he did my swap. He may be able to help you with the wiring.