Thread: Need advise from the OGs

Originally Posted by Itchy2500

I don't know if you can run a 97 PCM in a 99 even with the harness.

There's about a 13 wire difference to the pcm. But... I called Scott out on it and suggested using the 99 harness instead. It's very easy to mod a harness. Ask me how I know.

My 97 Bonneville had a 99 L36 harness that I modded for the firewall connector (would be relay center in a W body) to work. Ran a 99 pcm. At one point before I had a dhp I needed to have the correct vin, hence I made an adapter from 97 pcm to 99 wiring harness connector. It's a lot of wires to map, solder and hope you get right on the first try because you literally have one night to do it. FWIW I turned the key and it fired right up.

Originally Posted by BillBoost37

There's about a 13 wire difference to the pcm. But... I called Scott out on it and suggested using the 99 harness instead. It's very easy to mod a harness. Ask me how I know.

My 97 Bonneville had a 99 L36 harness that I modded for the firewall connector (would be relay center in a W body) to work. Ran a 99 pcm. At one point before I had a dhp I needed to have the correct vin, hence I made an adapter from 97 pcm to 99 wiring harness connector. It's a lot of wires to map, solder and hope you get right on the first try because you literally have one night to do it. FWIW I turned the key and it fired right up.

Well Bill it turns out it's a 98. I know I'll still have to mod the 99 harness and will pm you when that day comes but since it's only a year difference could I use the 98 pcm?

Originally Posted by freestyler659

Well Bill it turns out it's a 98. I know I'll still have to mod the 99 harness and will pm you when that day comes but since it's only a year difference could I use the 98 pcm?

if its a 98 pcm from the gtp, and your car is a 99 you could flash a 99 bin to it and make it work with some tuning changes like the tranny if you keep the na tranny.

what im saying is you have two good pcm's now 98 and 99 will swap bins with no issue.

a 97 pcm is its own animal and can only be used for a 97.

if you ever figure out what way you want to go, pm me, i can make all them changes in the pcm for ya. you just need to ship me one of the pcm's.

Originally Posted by WileyCoyote

if its a 98 pcm from the gtp, and your car is a 99 you could flash a 99 bin to it and make it work with some tuning changes like the tranny if you keep the na tranny.

what im saying is you have two good pcm's now 98 and 99 will swap bins with no issue.

a 97 pcm is its own animal and can only be used for a 97.

if you ever figure out what way you want to go, pm me, i can make all them changes in the pcm for ya. you just need to ship me one of the pcm's.

Thanks Scotty! Yes I will send you a pm. As of now the gtp runs and shifts good so I'm going to swap both in at the same time.




I drove it home like this. That's a Pontiac for you