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1988 Grand Prix 2.8 to 3100 swap


1988 Grand Prix

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Hello, I have a 1988 Grand Prix that currently has a dead 2.8L w/ 249,092 miles. I bought a '00 3100 out of a rear-ended Malibu. I have posted this question on the 660 forum, and RobertIsaar, suggested that I post on here to see if anybody had any suggestions/ideas.

 

If anyone has any suggestions or success stories, I'd sure like to hear them. Anything that you think might make this swap go smoothly. Thank you.

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supposedly a 3100 will work on a 3.1mpfi chip, using the 3.1mpfi injectors. you might be able to update your car by using a 1989-90 wiring harness and a chip from a 89-90 car with a 3.1...

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Yah, I'm curious too.

 

What did all of you (those of you who swapped a 3100 into your older w-body) do to make it fit? I mean, are there any parts that have to be moved/modified to make it fit?

 

 

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chip has already been worked out.

 

whats the difference in the 88 and 89-90 engine harnesses?

the 88's had the MAF sensor that was notoriously bad and had to be reprogrammed for speed density? it may be possible to re-wire?

 

you need 3100 W-body motor mounts. that said, someone here may have them....

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chip has already been worked out.

 

whats the difference in the 88 and 89-90 engine harnesses?

the 88's had the MAF sensor that was notoriously bad and had to be reprogrammed for speed density? it may be possible to re-wire?

you need 3100 W-body motor mounts. that said, someone here may have them....

 

it already has the recall done for S-D. using PROM ASWH, which according to service bulletin 88-6-97, is the fixed PROM.

 

would it be possible to pull the mounts off of the 2.8 and bolt them to the 3100?

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Thanks Robertisaar, I was wondering about that too.

 

I don't see why the mounts wouldn't work. I've heard that a 3100 is just a newer 3.1 which in turn is just a 2.8 with a bigger bore. They used the same block I think.

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I don't see why the mounts wouldn't work. I've heard that a 3100 is just a newer 3.1 which in turn is just a 2.8 with a bigger bore. They used the same block I think.

 

not identical, but VERY similar.

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Oh.

 

So, would the motor mounts off of the 2.8 work?

 

thats what i was suggesting...

 

they should as long as they bolt up the same way they do on the 2.8...

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Oh.

 

So, would the motor mounts off of the 2.8 work?

 

thats what i was suggesting...

 

they should as long as they bolt up the same way they do on the 2.8...

motor mounts are the same... BRACKETS are different. you need the W body specific 3100 brackets.

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Boy Garrett Powered, you sure like the rare turbo Grand Prix. I like that.

 

In order to get the motor mount brackets from a junkyard, I would have to take the motor out of a junked car.

 

If I absolutely need these brackets to make it work, I would appreciate it greatly if someone would find them for me and PM me. I will gladly pay you something for them. In the PM I will give you my address. Thank you!

 

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I'd like to get this project started sooner than later. :burnout:

 

If you can't get them for a week or so, that's ok. Im not in that big of a hurry.

I'd just want them before Halloween.

 

Thanks!

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Boy Garrett Powered, you sure like the rare turbo Grand Prix. I like that.

 

 

you gotta love em. there is a lot of good cars made around that time by GM.

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you can reuse your upper mounts (they will line up) and your lower mount. BUT you will need a lower mount bracket if your engine doesn't have one attached.

 

Things you'll need:

 

- Accelerator cable and cruise cable

- custom mount for transmission TV cable to the throttle body

- wiring harness, or modify your existing one to account for some different connectors (alternator, knock sensor, etc), different location of a few sensors and the ignition coils

- I think the coolant hoses between the engine and heater core are different. Also you'll need 3100 coolant bypass tubes if you don't already have them

- Power steering pump from a 3100 along with pressure hose and maybe the return hose too

- Exhaust downpipe between rear exhaust and catalyst

 

I'm sure I'm missing more but that's something to put in your pocket to start with.

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i disagree?

 

I don;t think the mounting on the engine for the dogbones will swap between engines, and his will not have the dogbone mounts, i think.

 

hell... do you already have the motor? take pics of it!

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i disagree?

 

I don;t think the mounting on the engine for the dogbones will swap between engines, and his will not have the dogbone mounts, i think.

 

hell... do you already have the motor? take pics of it!

 

he has it.

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