We have gas to rail, fuel pressure good, pump working, we have spark, car crank and cranks, tried changing ignition module, tried new camshaft position sensor, same symptoms but will run on Ether(Starting fluid). The noid lights and procedures I did was pointing to wiring or problem with main brain or ecm unit because gas to rail but no fuel injection pulse. Very aggravated brain or shoted wire?? Am I in right area?? Thanks Chris from CavicsAutomotive Service
Electrical power (12 volts) is supplied to the fuel injectors from the LTR/Horn Inj fuse, 20A. Check it. The power divides into two branches (pink wires). One branch of pink wire goes to FI #1, #3, #5. The other branch of pink wire goes to FI #2, #4, #6.
Each set of three (3) fuel injectors are fired at the same time, NOT each fuel injector, individually. One set of FI (#1, #3, #5) is controlled by the dark blue wire which goes to terminal C11 on the ECM (engine computer). The other set of FI (#2, #4, #6) is controlled by the dark green wire from the FI to the terminal C12 on the ECM.
Check (ignition switch RUN) for 12 volts dc at the 20A fuse, AND at C11 and C12 at the ECM. If you don’t have 12 volts at C11 and C12, there are shorted, or broken wire(s) between the fuse and the ECM.
With the engine cranking (or, running on ether) backprobe the ECM at C11 and C12, with a digital multmeter (“voltmeter”). The voltage should change from low volts to 12 volts each time the ECM is firing each set of (three) fuel injectors.
If the voltage action, of 12 volts to low volts, 12 volts to low volts, etc., isn’t there, troubleshoot according to the DTC charts in the repair manual, or at www.alldata.com.
The fuse box lid, on the right fender, may be mislabeled for the fuel injector fuse. Look UNDER the fender mounted fuse box for the large pink wire. Follow the large pink wire to the correct fuse.
To recap the test, you want to check for voltage from the FI fuse (ignition switch RUN) to the ECM (engine computer) terminals C11 and C12. If voltage doesn’t get to C11 or C12, it’s being lost by an open wire, or a wire shorted to ground. To fully check the wiring to each fuel injector, you’ll have to take the intake manifold off.
Thanks I been testing Im going to be running the rest tomorrow, got swampped with other work. I wanted to take the time to thank you.
Chris Cavic
Cavic’s Automotive & Tire Center
PA-USA