I am thinking about buying a replacement ECM from Rockauto for a 3.1L. They have three - Stantard Motor ($77), A-1 Cardone ($78), ACDelco ($106). Any recommendations on the which one is better, worse? Prices are pretty close. Or should I get one from a junk yard? Mike

 

How 'bout this one?

 

if you can find a 165 ECM in the junkyard, thats the way to go. I'm heading there tomorrow hopefully with luck this time. Re-pinning the ECM connectors for it is a snap. Only thing you need but might not have is an eprom programmer. I paid $40 for mine through Mcumall.

 

on a 3.1, down grading to a 165 isn't the way to go. the 3.1 has the 730 ecm. the same (basically) as some v8s. There is a lot of good tuning software available for it and emulators...no need for an eprom programmer then.

In answer to the OP's question, I don't imagine there's a difference in any of those, performance wise. As far as quality, I'd say AC Delco. I assume you are having problems with yours? If so, what?

 

Sorry so long to reply - I don't have a good answer to why th ECM. I did figure out why the engine was stalling when I stepped on gas. I replaced the TPS and fixed it. I drove the car and still surges but when I got home the idle was very rough but it was smooth before I drove around the neighborhood. I cleaned the IAC valve but no help. ECM seems like a possible fix but I also think the vavel prepoad is still a little to much (5/8 turn after zero lash). I planned to check compression in a few days. thanks Mike

 

Valve lash should be between 1/4 and 1/2 turn... As for the ECM, if you can't possibly get an AC/Delco, get something with a decent warranty because I can almost guarantee it's going to crap out again. I've had one and seen one that were both remanned that had serious driver problems (the one in my ECM had a transistor literally broken in half).

 

My buddy did the '302 to '730 swap. It seems just as easy as the '302 to '165 swap with the added benefit of having a '730 (and ditching the MAF). I had the idea of doing this swap a few years ago and picked up a junkyard '730 for $30.