Chart A-5-A Injector System Diagnosis

PFI Chart A-5-A:

Fuel Injector Circuit:

DESCRIPTION:

The fuel injectors are powered through two 10.0 AMP injector fuses. The ECM 1 C/D connector pins C12,D13, D15, D16, C11, D14, C15, and C13, injector drive circuits. The ECM grounds the injector drive circuits to turn on the fuel injector to supply fuel to the engine. ECM data parameter P.1.2 injector pulse width, reflects the time in milliseconds that the ECM turns on the ground to the injectors for each injector pulse.

NOTES ON FAULT TREE:

1. The injectors will not spray unless the ECM receives distributor reference. If code E12 is current, it must be repaired.

2. Using injector override, perform an RPM drop test by cutting off the fuel to each injector on command, using the on board diagnostic system. If any cylinders do not cause an RPM drop of 100 or greater when fuel is shut off to that injector, the cause could be fuel, spark, or mechanical at this point, but the problem has been isolated to the affected cylinders. Further diagnosis is required. To perform the rpm drop test, enter diagnostics, and select injector override E.5.4. Depressing the warmer button with E.5.4 displayed will select which injector will be shut off, and depressing the cooler button will cause that injector to shut off.

3. Injector flow override E.6.0 will actuate each injector for 5 milliseconds. Depressing the warmer button will select an injector to be tested. Depressing the cooler button will actuate the selected injector. A selected injector can be actuated only once in a given key cycle. To actuate the injector again the engine must be started, This is to prevent the engine from being flooded or damaged.