Posted: Wed Feb 01, 2012 12:26 am Post subject: L67 swap
Well, when I was looking for a MAF sensor I found a '01 Grand Prix GTP with the complete engine and transmission, the darn thing is SUPER clean with low miles (65K) I'm thinking of buying the complete engine and transmission harness and PCM, The price of the engine is very good too, they want 800 for the whole package. The only thing missing is the MAF sensor which I bought
My question is, can I use the harness and PCM from the Grand Prix on the Impala?
I know the Transmission is compatible but I wonder if the PCM is too.
You can't use the GTP bin file, it doesn't play nice with the Impala/Monte BCM. You need a Monte SS or Impala SS bin file (you should be able to program the GTP PCM with the correct BIN file and VIN number)
You also need to do one of the following:
1 - Use the GTP engine harness and modify it
2 - Use the GTP engine harness and remove some codes from the PCM
3 - Use the Impala/Monte SS SC engine harness
Double check with nightryder...
PS: 65K miles is not necessarily low miles for the tranny...
You are going to want to do the tuning yourself, there's no doubt that Will has the knowledge to do what needs to be done but you are doing a modification to an '01 Impala that only a few have done successfully. It will make your life 100x easier if you know how to operate a tuner and troubleshoot with it instead of trying to diagnose and then send the PCM back for a retune. I'm not certain exactly what Will does for situations like this but I would assume he will use the N/A .bin from your car and modify it so it's safe for boost. The car will run fine this way, but you will be limited by your tune. I also have no first hand experience with doing it this way, I know the theory behind it and it will work. Rest assured, this isn't just a "swap in a L67 engine/PCM and go" kind of modification when dealing with a <'03 Impala.
What I did (IMO, the best way to do it) was use the stock '01 PCM and then I flashed a '04 L67 Monte SS file to it and tuned from there. You will need a DHP tuner to do this. Use the stock '01 harness and buy a 2 bar MAP sensor from a '04+ Impala SS (plugs right into the '01 harness), no further modifications are necessary. The BCS is useless so long as you are a diligent driver and know not to cruise in boost. If your car has califorina emissions (secondary air injection) you will need to remove all the hardware and plug the hole on the exhaust manifold (the '04 file doesn't support secondary air). You will also need to delete the DTC's that will show up for the heated O2's ('04+ has PCM controlled heaters in the O2 sensors).
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