swaping a 90 w/stick ecu for a 92 w/stick ecu

[ogrefish]

Hi: brand new.. own 2 subaru.. 1990 Legacy Wagon manual 340,000 miles .. second owner... 1992 legacy wagon manual.. 180,000 miles... runs great

I am having issues with the Air Flow Sensor... code... starts perfect, as soon as it warms... quavering idle and dies when coming off of higher rpm.... woulds like to swap out Air flow from a 92, because the 90 manual is different than all the rest... would like to make it like the 92... have ECu and Airflow from 92... but changing that doesn't make it run... anyone know what else i would need to do to make this swap work?.... or maybe a link to a 90 service manual so I can diagnosis properly as the 92 service manual has different data, wiring etc... Thanks for listening

pat

[Legacy777]

Hi Pat & welcome to the BBS.

There are also differences with the injectors, idle air control valve, and other miscellaneous wiring. Unfortunately the 90-91 manual trans Legacies are slightly unique and aren't as interchangeable between the other years.

My recommendation would be to try and find another Hitachi MAF for the 90 Legacy if you believe that is the problem. Those MAF sensors are found on the 90-91 non-turbo manual trans legacies as well as the 91-94 turbo Legacies. I'd suggest posting in the Parts Shed to see if anyone has one for sale.

[ogrefish]

Thanks for the reply... I have found a problem that might be the ghost I have been chasing... I have a constant voltage to injectors of the 90 even with the key off... but without the book.. I don't know if this should happen... I know it doesn't happen with the 92... my son and I are playing with the 90... we swapped the ECU, Air Flow and Air Idle and it seem to run well; but... we did get 4 codes that showed up( even though the CIL doesn't stay on).... thanks again for the info... didn't know the Air Flow sensor also was on the 91-94 turbos... that helps

[Legacy777]

On the 90 MY the injectors will get a constant 12v regardless of the ignition; that behavior is normal.

There is one additional wire for the idle air control valve on the 92 compared to the 90.

Regarding the diagrams and manuals, I urge you to review the stuff you need to know forum. If you do, you'll find this thread

Here are direct links to some of the wiring diagrams you need:

http://www.main.experiencetherave.com/s ... agrams.zip

http://www.main.experiencetherave.com/s ... and_Elect/

[ogrefish]

Thanks very much

Pat