Computer questions for tranny swap

Am going to stroke a '90 4.0 Renix engine to go into an '84 CJ8. Thinking of using an AX-15 or maybe a 3550. My question is, is there a difference in the computers depending on whether you have an AW-4 or and AX-15, or...? And, can a computer from an AW-4 be used for a manual tranny?

Have done some searching and reading, particularly Dr. Dyno (of course), but haven't stumbled on anything yet.

The renix system uses separate computers for engine and trans. The renix engine will run perfectly fine without the tranny computer.

The computer between an auto and a manual are different. The auto version has a couple of more inputs that handle functions like the NSS if I remember right. When I swapped from a manual to an automatic, I swapped the computer, even though It would have most likely worked. I still have the manual computer from an 89/90. If you want, I would swap you. That way you have a manual computer and I have a spare for the auto.

old_man said:

The computer between an auto and a manual are different. The auto version has a couple of more inputs that handle functions like the NSS if I remember right. When I swapped from a manual to an automatic, I swapped the computer, even though It would have most likely worked. I still have the manual computer from an 89/90. If you want, I would swap you. That way you have a manual computer and I have a spare for the auto.

Click to expand...

Hmmm. That has posibilities. I don't actually have the ECM yet. I am picking up the engine this weekend and can get the computer (for the AW-4) too. Problem is I still will need a wiring harness.

Good point on the NSS. If I use an ECU meant for use with the AW-4, will the lack of a signal from the (ain't got one with a manual) NSS cause a no-start? Or will I be O.K. as Slip-Kid says?

Just trying to get my ducks in a row at the moment.

I think you will be OK. If I remember right it also has an input from the auto to boost the idle when you put it in gear.

The Parts List shows #5300-5429 for the manual ECU and #5300-5428 for the auto ECU. Not surprising that they would be different, based on what we have already discussed. Doesn't mean the auto ECU wouldn't work with the manual. I am guessing the manual ECU wouldn't work with the auto though.

Guess I better learn how to read a FSM wiring diagram....