Thread: Any probs. with '94 3.1?

I am in the process of getting a '94 3.1 for my '88 Grand Prix. I was just wondering if there were any problems with the 3.1 motors that I need to know about before I swap it in?

The only real downfall to the 3100/3400 motor was GM's retarded idea of using nylon/silicone for the intake gaskets, which were inevitably prone to failure. When the LIM gasket goes, depending on how bad the sepage is into the block, it can either lock up the motor, or the coolant destroys the bearings, leading to a spun bearing.

The other issue is the '94 uses an OBD 1.5 (an OBDI/II hybrid), where as your '88 is an OBDI. This might be a wiring nightmare for the swap. I'm not positive on whether you'd need to change wiring, the computer, etc.

I'd just try to find something pre-'93 IMO...that way it is a direct swap.

Also...just change all the gaskets while the motor is out

and what engine is in the 88 prix now? the 2.8? and you are going to the 3100? or pre 94 3.1? even if it is a more direct swap from a 93 and less for a 3.1 dont you have to change the prom chip in the pcm?

It's the 2.8L. The only GM to get the 3.1 in '88 was the very limited (124 made) Pontiac 6000 STE All Wheel Drive. And if it's truly a '94 he's picking up, it would have to be the 3100. Changing PROM chips is a breeze. It's changing out all the wiring and computer that would be a serious pain in the ass. If he's going to go through all that, he'd be better off getting a '00 & up 3400, and swapping over to an OBDII computer. More power to start with, plus a lot more easy to tune.

I actually just bought a '00 3100 last week. I have talked it over with guys on the 660 forum, and I don't have to do a whole lot to do this swap.

I can run the 2.8's ECM, injectors, and motormounts. That way it will be a lot easier to deal with.

Those 60* guys know their stuff...good deal you got it all figured out man!!

Thanks, I hope so! I just got the new motor unloaded from my dads S10 last night, and I hope to start disassembly of the 2.8 tomorrow.

Here are some pictures of my car and engine. Any constructive comments or suggestions will be accepted. Thanks!

Some of you may have noticed that I may be missing some parts. I want to let you know that I do have all the parts.