91-94 Ecu In A 90

[Nash]

After doing some research I think I know all that needs to be done to get a 91-94 ECU to work in a 90, but I just want to make sure. This is what I have found so far. The MAF Reset line and the Idle Switch lines need to be swapped and you need to put in a '91-94 ignition transistor. Does anyone know if I'm missing something?

[Jakey]

Andy could you explain a little bit the benefits of switching the ecu to the 91-94?

[Shane@DBPerformance]

It's too hard to find an 90 EPROM ECU.

[Nash]

Like Ecoli said they are hard to find. From the research I have done the only 90 EPROM ECU's were in 1.6 Turbo Mirage/Colt/Summit.

[Kracka]

Nathan Helder in Duluth did this swap, I believe all he had to do was switch around a few wires down at the ECU.

[Nash]

Did he do a 90 to a 91-94, or a 91-94 to a 90? I think you can just change the wires when doing a 90 to 91-94, and it will work. But when doing a 91-94 to a 90 you need to put in a 91-94 ignition transistor or the tach won't work.

[JET]

I think you are right Andy. I know the 90's need a different tach input for the MSD ignitions.

[At-Least-It's-An-Evo]

Originally posted by Nash@Dec 2 2003, 05:21 AM
Did he do a 90 to a 91-94, or a 91-94 to a 90? I think you can just change the wires when doing a 90 to 91-94, and it will work. But when doing a 91-94 to a 90 you need to put in a 91-94 ignition transistor or the tach won't work.
I believe his is a 90 gsx, so he probably went from 91-94 to 90.

[Nash]

I found this site http://www.ecanfix.com/~mdhamilton/ecuconversion.html.

[Jacek]

is there anything special about the eprom chip? is it just because you can slap a different chip in it?