I'm in the process of switching my '87 gta 305ci, 5speed, maf to a speed density 350ci. I have an ecm and wire harness out of a '91 Formula. I noticed that the sd fuel pump pins going into the firewall on driverside didn't match with the cars original set up on the other side, so I had no fuel pump. I also noticed my injectors weren't pulsing either. If there is anyone that has converted to sd by this method I would appreciate the help on how to either repin the bulkhead going into firewall (on driver side) or any other info. Also if someone knows how to convert the harness from 700R4 to work with my t5. Thanks....

 

Did you get a modified prom to eliminate the VATS?
I do know that the fuel pump relays on the 91+ cars look different, they are kinda round while the ones I used on my 86 were square.

 

No, I just ordered a brand new harness from GM. One of my friends gave me his oval style relay's though.

 

He is using my ECM (vats enabled). He has the correct relays...the ecm is kicking on the relay during fuel prime and during the ignition pulse signal.

I'm trying to get a feel if people think that purchasing a MAF harness to repin acording to the tech article would be easier or if there is any information out there for how to repin this 91 harness for his 87 car. Thanks!

Swapping in the 91 wiring harness will require repinning the driver side bulkhead which is not discussed in the tech article.

 

If someone could direct us to "driver side bulkhead" pinouts for 87 GTA 305 TPI and 91 Formula 350 TPI we could take care of this problem I think by cross-referencing the diagrams.:hail: