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Swapped engine, trans, and pcm now no start

mrlogic1234

mrlogic1234

New member
Hi recently we swapped the engine, trans and pcm from a 05 GTP to a 05 GT and we can't get it started. All the dash lights come on and we have power to the starter, but nothing happens when we turn the key. Any suggestions from the experts would be greatly appreciated.

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When you say power to the starter, you mean constant power at the big gauge wire, and also power at the solenoid wire when you turn the key? If you have both those, and the engine/trans ground hooked up, either the starter goes or it's bad.
 
Fivefingerdeathpunch said:
All grounds are hooked up and snug right?

No blown fuses?

Maybe swap the GT pcm in and see if it starts.
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I was thinking about doing that but I was afraid of messing something up with the engine because one is made for a sc car and such. I'll double check the fuses. Do you think it could be pk3 related?

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02NavyBlue said:
When you say power to the starter, you mean constant power at the big gauge wire, and also power at the solenoid wire when you turn the key? If you have both those, and the engine/trans ground hooked up, either the starter goes or it's bad.
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Yes we've check all the connections over a few times. I was curious if you think pass key 3 is locking us out? Considering the wiring harness, and pcm is from the donor GP with different keys and programming...

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Well when I meant check it, I meant get under and check it right at the starter. You can see if you're getting power right to it (at the solenoid wire when the key is turned to crank) If not, then I'd check connections(you did) and lastly, things with security like passkey or something.
 


dont the PCM and BCM need to have the same vin for everything to work? so if you swapped the PCM that came with the new engine, but not the BCM you would have mis'matched vins.
 
I missed seeing one of the starter wires once after a motor install once. I believe there is three wires and one of them was hiding. There's also a ground or two on the trans. I missed seeing one of those once too. Lol
 
I'm thinking what fivefinger and orange touched on... swap PCM and see if it starts. Car will run with the GT PCM, but not "great" But if it starts with your original GT PCM then you know there is miscommunication between your stock BCM and the GTP PCM out of the other car.
 
Ok here's where we are... we put the gt pcm in and it started. So after that we had it towed to a Chevy dealership and had them program the Gtp pcm to the vin. Now it runs, but like crap. Something regarding the map sensor we were told.

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If they programmed the pcm to the vin, they put in the NA tune I'd bet. Because when they pull the most current tune for a vin..that's what they'll see.
 


darkhorizon said:
You just need a GTP pcm... You had one but for some reason you had them flash it back to the same pcm you already have????

You need to go and (buy) another PCM then sync it to the BCM. PCM relearn procedure
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We only did that because it wouldn't start with the one from the GTP. The idea wasn't to get a GT tune flashed on the GTP pcm, and I'm not exactly sure if that's what the dealership did or not. I'm posting this for a member in my local car club because he's not on the forums. I must have did a terrible job of searching, I couldn't find the answer anywhere on here. That was the reason for this post. I appreciate your willingness to help.

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might be a good idea to share what map sensors you have on this, because you have to have a very specific combo for each PCM for things to work correctly.
 
darkhorizon said:
might be a good idea to share what map sensors you have on this, because you have to have a very specific combo for each PCM for things to work correctly.
Click to expand...

The engine and trans including all sensors with the exception of the oxygen sensors were from the donor car. (GTP) Even the wiring harness is from the GTP.

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Btw, that whole let me Google that for you thing was kinda funny... I'm not one to just post random questions without searching first. I didn't see any threads on GPF with my exact issue.

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