1g 90 ecu differences

[sly mantis]

Hi
Ive been reading and heard that the 90 ecu is somehow different then the rest of the 1st gen ecus.
How is it different from the others?

 

[JayRolla]

Im not sure what the difference is but I do know you need to swap two pins to make it work correctly. Search you will find it.

 

[Gromit]

Hi
Ive been reading and heard that the 90 ecu is somehow different then the rest of the 1st gen ecus.
How is it different from the others?

If you try to use an unmodified 91-94 ECU in a 90 car the dash tach will not function correctly.

Look here:
http://www.dsmchips.com/1990ecu.html

and here:
http://www.ecanfix.com/users/mdhamilton/ecuconversion.html

for what is required to get it to work right.