'90-92 3.1 swap

I swaped eng. and transaxle forom a 90 Lumina to a 92 eruro. Afew things had to be swaped such as AC compressor bracket, fuel lines and such. The swap came about due to transaxle in '92 had no forward. I changed the position switch. Now when starting the car, the alt. won't charge, and it acts as if the timeing is way off. Do I also have to change the ECM computer? And if I do what will be the effect on the ABS sys. that the 92 has and the 90 didn't? I know it sound strange toi swap out for an older motor, but there was a 100,000 mile diference. Also because I had to pull everything at once anyway........ I did notice that the harness that hooks to Alt. on the 92 has only 2 wires and the other has 4. Any ideas? I need to finish so I have something to drive.

There shouldn't be many issues on the engine, as long as both are Vin-T 3.1's. Assuming both cars have overdrive, there could be a trans issue, as the 90 had only a 4t60 (ME9 option code) non-electronic trans, and the 92 could have had a 4t60 or 4t60-e (M13 option code) electronic trans.

Tranny shifts fine. On the main harnesses that connects from ecm to the motor (2) there is a difference in the color code from one to the other. I swapped out the ecm w/ same reults. both motors ran great before swap. I will remove the cableing from the '92 and put on the '90 (now in the car) when the tropical sun goes down a bit and it's not so damn hot.

PM me if you need connector end veiws of the ECM's, i may be able to help you out.