Fuel delivery, ECM,or something else is fixed

[maric734]

I started with an 89 XT that was only running on 1 maybe 2 cylinders (#1,#3). After doing some trouble shooting (which I describe in earlier post) I decided to check the wiring harness. This is where my problem was. There were factory splices in all 4 wires that feed the fuel injectors. I know it came like this because the wiring was still in factory foam rap under the carpet on passenger’s side. Why this was done is the mystery, must have to do with the different types of fuel systems (carb, spfi, mpfi) that were available. The ECM just works as a ground in this system so check all voltages at the pins and resistance or voltage of component. You can also check the fuel pump relay this way for those of you that use toggle switches for your fuel pumps!