: Please help with PCM issue on 1993 Allante

06-09-14, 06:45 PM
My dad just bought a 1993 Allante with the Northstar. It was running really rough and rich with P025 code, so I shut down 1 injector at a time to see what (and if) cylinder was the culprit. Turns out 3 and 8 did nothing when shut down, so I replaced the coil. Car ran much better but still a little rich and slight miss. Checked and P025 was back. Cleared again and it came right back. I have done the diagnostic tree for P025 and everything shoots toward a bad PCM. The part number on the current PCM (it is a reman from GM) is 16180517. My dealer and AC Delco say that the part number is the mid-year intro PCM and that I should have part number 16159277 or 16207768. AC Delco says it's not discontinued but don't know if or when they will get more and can't tell me if the other unit can cross over. I really would like the AC Delco model... Does anyone know if the
mid-year model will work? Obviously it is in there now and drives, but is that the reason it is missing and running rich?

Thank you for any help!!!!!!:worship:

06-09-14, 10:15 PM
Running rich? Have you checked for a leaky FPR?

06-10-14, 12:51 PM
No, net yet. Thanks for the advice, I'll check that out too. I wanted to get the PCM taken care of first. After changing the coil it took care of most of the rich problem.