1989 f-150 Engine, Tranny, Wiring Harness Computer issues
 

I have a 1989 F150 that i put a 351 in (replaced the old 302) I also have the original transmission and wiring harness used with the 302. The tranny has been rebuilt and the motor is a reman. I have everything put in but the truck still is not running right. Have been told it is the computer issue. So I pulled a computer out of a 1989 Ford Bronco that has the C-6 tranny and a 351 in it but still is not running right. My mechanic keeps saying it is because the numbers do not match on the computer and it wont pass emissions. He has also told me that it is going to be almost impossible to find a matching computer for the tranny, motor and wiring harness. Wondering what my options are?

Not running right how? I can't remember if a 89' 302 had a H.O. firing order, but in theory if you put a 351FI motor in place of a 302FI motor the computer wouldn't know.

I put a H.O. SEFI computer in place of a standard SEFI computer in a Cougar i had and it ran like a scalded ape. Broke the motor mount and overpowered the stock AOD.

well it wont shift out of first gear (Tranny has been rebuilt and was checked again by the company that did it). Verified the linkage is all correct. And the truck keeps stalling out. Brand new reman motor as well as new starter, battery, alternater, water pump, etc. Everything has been replaced with new or rebuilt parts except the wiring harness and the computer basically. Was told the tranny wont shift because the computer is differant need a specific code for it. Also was told the motor is stalling out because the code does not match that motor for the computer. Also been advised that the truck will not pass emissions unless the code for the computer matches the motor and the transmission.

On another note had differant mechanic tell me to put a computer in from a ford desiel pickup and it would solve my issues. Any thoughts on this?

Yes, 89 computers don't control the transmission.

Start with the basics, double check your wiring and timing.