91 3.1l to 95 3.1l swap?

[mgosse]

I have a 1996 Grand prix that recently lost the motor, the body is in impeciable condition and i really dont wanna thow the body away, With that said I also have a 1991 Grand Prix 3.1 with and excellent running engine and trans but the body is toast. Is the Motor from the 91 a direct swap into the 96? The motor and trans seem to be the same to bolt in but my concern is the wiring hooking up fine without making a mess of a harness. Any input would be greatly appreciated.

[bszopi]

First off, welcome to the site.

Secondly, its illegal to put an older engine into a newer vehicle (mainly an emissions thing). But, lets say you don't care about emissions...

Its not going to work because the older engine doesn't have all the sensors that the newer PCM is looking for, therefore its basically going to cause SES lights and/or force the PCM into Limp mode. Not an ideal situation.

Long answer short, unfortunately it won't work.

[mgosse]

Thanks, Im glad for the input, Guess I'll look for a newer engine,

[mgosse]

I was also wondering, I have a full running donor car with the 3.1. Iis it possible to swap the harness and pcm and make it run fine?

[Superdave]

the PCM controls the trans in the 96 so you'd have to leave it hooked up and piggy back the 91 computer to run the engine basically running 2 wiring harnesses through the car. completely not worth it. You'd also get worse gas mileage and have less power (about 20 HP difference) with the gen2 3.1.

Now is a good time to swap out the old 3100 with a modern 3400 or a 3500.