Sometimes you just cant get to the car to reflash the ECM. Maybe you want to run a tuning business by mail or your like me and just looking to put something where it just doesn't belong. Like swapping a new fuel injected motor into and old hot rod.

I saw efilive had a nice PDF about bench wiring your PCM. I made a little adapter board just for GM PWM PCM's. This way I can flash a tune and leave the outside work for later....

Step 1: Just the Basics

I added an ALDL connector and a toggle switch for the ignition. In addition to power and ground I only wired pin 2 for the serial data since I only work on older GM stuff. You can add more pins if you want like CAN or GMLAN etc.

I added an alternate PCM connector. Its a 5 pin header that connects to a short cable with RS232 pins on the opposite end. The old RS232 pins fit pretty well onto the GM PCM pins. just cover them with a little shrink tubing and your done.

Step 2: Testing the Interface

Before I trust it to my expensive interface I'll test it out using elmscan and a $12 ELM327 box. If I get a good initialization I'll connect the hp interface next. Then flash a new tune and get it ready to be installed....