Quote Originally Posted by dave w View Post
Using the 4 pin module works for a "Fuel Only" TBI system, meaning no spark control from the ECM.

Likely, if one injector is working, the 4 Pin Ignition Control Module is working fine.

The ECM has two injector drivers, maybe one of the injector drivers is bad?

dave w
I also replaced the ECM, if the "driver" is a software driver, and had the same issue. Since then, I put the old ECM in since apparently it was okay (since no change, now I have two ECM's ... good or bad I do not know. Too much diagnosis by wallet, I desired to go a bit more high tech and found this forum. I am really thankful for all the support, and am now over my head. I am an engineer, so can handle a bit of technology.
The steering column was removed, and harness from the ECM was inspected as OK. Continuity checks proved good. All the grounds are new, as well as the frame. Using a test light to D16 and D14 proved I had a light at D16, but not D14 with ignition on.... Hmmmm. This led me to an open circuit on on 468 LT GRN (which was included in the steering column drop and pulling the ECM connectors out for inspection. Again. No issues, breaks, bends.. Going to Injector circuit diagnosis, I can not tell with the system I have if I am getting a reference pulse from the ECM.