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Discussion Starter · #1 ·
I have a 99 grand am that i put a 3800 supercharged motor ,tranny and axles. I used a 2000 grand prix GTP motor, tranny axle and wiring. I got the motor in and all hooked up but when i used the 2000 grand prix PCM. It would not let the gauge cluster work. The signal is different and the theft system keep kicking in too. So i put the stock grand am one back in it. Then it started up and ran but it ran rich and the tranny did not shift right.But everything else worked. So i need to find a 3800 supercharged PCM that has the same signal as a grand am. Or someone that know how to make a hybrid PCM. Does anyone have any answers.
 

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You need to use the computer and wiring from the GTP. To disable the Pass-key system you'll need the BCM and the ignition key from the donor car.

The dash and other parts will need to be rewired.

Great project.

-T
 

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Discussion Starter · #3 ·
I can buy a PCM with the theft removed. But i do not know how to get around the cluster. I could not find any wiring on the IPC. That is the wiring to the cluster. I rewiring everything else. And had no problem finding wiring on everything else but that. That is what i am have problem with?
 

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Do you have accurated wiring diagrams for the car? I'm not two familiar with the GA's instrument cluster, but you'll probably be splicing the wires coming from the old computer. Have you wired the fans, fuel pump, ect?
 

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Discussion Starter · #5 ·
Yes i have the wiring on the 99 grand am and a 2000 grand prix. But i could not find anything on the wiring from the PCM to the cluster. Plus the signal is different form a grand am and a grand prix. Say the grand am is speaking english and the grand am is speaking spanish. This is the easyest way to describle it. Not sure if wiring will to it? It can not talk to the cluster. That is my problem. That is why it has been a hard problem to fix. Everyone i have talk to that build PCM do not know what to do. Hope this help you understand.
 

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one place i found a lot of wiring diagrams is actualy the local library. I had to go to Milwaukee's library, (my small town didn't have it) But go up to the reference desk and ask them for a service manual with wiring and vacuumme diagrams for your car, (might have to ask for a general GM of your year to find it).

p.s. i have a set of grand am rims for 225 bucks if you want. Or I can split the set if you want a pair for track tires. They are the slanted 5 stars. Painted. Great condition. minor scratch on one of them.
 

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You might want to try talking to someone at Delphi (maker of programable PCMs for GM) and see if they could fab one together for you and program the inputs and outputs to the correct pins on the PCM.
 

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newfinish said:
Yes i have the wiring on the 99 grand am and a 2000 grand prix. But i could not find anything on the wiring from the PCM to the cluster. Plus the signal is different form a grand am and a grand prix. Say the grand am is speaking english and the grand am is speaking spanish. This is the easyest way to describle it. Not sure if wiring will to it? It can not talk to the cluster. That is my problem. That is why it has been a hard problem to fix. Everyone i have talk to that build PCM do not know what to do. Hope this help you understand.
It sounds like your talking about a digital signal. The grandprix does not use this for the main gauges, unless your thinking about the DIC?

You should have no problems running the tach, speedo, temp, and voltage.
 

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Discussion Starter · #9 ·
99 grand am with a 3800 supercharged motor

I think that because the grand prix PCM has a analog odometer and my grand am has a digital odometer. That might be the differents? Do you know of any cars that have a 3800 in them with a digital odometer and that barries the gauge and reset it self at 0 when you turn the key? Just like my 99 grand am. The PCM might work out of it? Maybe the signal will be the same to the cluster? Anyone have any suggestions?
 

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PCM to IPC wiring schematics

can buy a PCM with the theft removed. But i do not know how to get around the cluster. I could not find any wiring on the IPC. That is the wiring to the cluster.
Here are some schematics, I hope these help....if they upload. Otherwise email me and I'll send them to you.








 

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Discussion Starter · #12 ·
I have put pictures of the 99 grand am with a 3800 motor in it on my web site. You can see it at newfinish.com.
 

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Discussion Starter · #13 · (Edited)
www.newfinish.com Here are some pictures of the 99 grand am with a 3800 motor. It will tell you how i did it . When you go to this link click on the grand am link at the top of page. Then at the bottom it will show you page 2 and page 3. I hope this help you find it ok.
 

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for everyones information the GA uses a class 2 data signal like the DIC from the GTP. Now what he is trying to do is a run a digital dash with a analog system. This will not work. Some L67 powered cars with the same dash as his. What he needs to know is what years those cars were then prgram his BCM to the VIN from that car and PCM to match. I am pretty sure that will work
 

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the ga is Nice, and the fact that you put 12's in the trunk of the gto...priceless. nice cars. very nice.




newfinish said:
www.newfinish.com Here are some pictures of the 99 grand am with a 3800 motor. It will tell you how i did it . When you go to this link click on the grand am link at the top of page. Then at the bottom it will show you page 2 and page 3. I hope this help you find it ok.
 

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sweet project man, make me jealous.
 
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