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I know you guys are always looking for 90 Eproms, but is it a big deal to use the 92 ECU in the 89 Mirage? Besided the two wires you have to switch is it only the issue with the Tach signal?? Its been so long since Ive have to deal with this I cant remember.

I have my DSM link in my 91 Galant VR4 right now but Im going to swap it back to my Mirage. I dont have the tach filter any more because Im using the tach signal from the DIS-2 so I think I wont need to worry about that. Car has spark, just dont know if the tach is going to work.

It's the same as putting a 91+ ECU in a '90 DSM, you have to swap pins 6 and 14, and the tach won't work, but the car will run fine.

I know on a 91-99 you can cut the white wire on the transistor and feed it with the tach output from the DIS-2 so you dont need the tach adapter, should that work with a 89-90 car also? Only difference would be Im using the 4th Yellow wire from the Coil pack Harness??

I don't know to be honest. There is something physically different about the '90 ECU's that changes the way the tach works, it nothing to do with any of the ignition components.

The 90 ECU's are different because they require a noise filter. I'm sure it could be rewired like they are in DSM's. I believe its only 2 wires that you have to change around.

If all your worried about is the tach, why dont you try a tach from a 91-92 CSM. Its a theory but I think that the 91-92 12 valve 1.5l cars did didn't need the filtered signal.

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

keydivers site has alot of info. it may help you

Well I talked with that Keydriver guy and pretty much what he told me was 89-90 cars Tach and ECU use a Positive pulse to run the dash tach and the ECU. The Tach interface coverts that signal to a positive pulse. I need to leave the tacho interface in place so my tach will read correctly and then use the DIS2's negative pulse output and feed it to pin 109 for a tach signal to the ECU. Sounds like it will work I guess.