Chart A1-5 Fuel Injector Circuit Check

Fuel Injector Circuit Check:

Fuel Injector Circuit:

CIRCUIT DESCRIPTION
When the solenoid coil of the fuel injector is energized by the Engine Control Module (ECM), it will activate the plunger and pressurized fuel will be injected into the Throttle Body Fuel Injection (TBI) unit. The fuel pump will operate as long as the engine is cranking, and the ECM is receiving ignition reference pulses. If the ECM does not receive any reference pulses, the fuel pump will stop after three seconds.

TEST DESCRIPTION
Numbers below refer to circled numbers on the diagnostic chart.

1. Checks to see if the ECM is controlling the fuel injector signals.
2. Checks the fuel injector for correct resistance.
3. Checks for voltage at fuel injector.
4. Checks for an open or short to ground in YEL/BLK wire, a faulty ECM or a faulty fuel injector.
5. Checks for an open or short to ground in YEL wire, an open in WHT/BLU wire or for a faulty fuel injector resistor.

DIAGNOSTIC AIDS
There may be fuel spray at the fuel injector, but it may not be enough to start the engine. If both the fuel injector and the circuit are OK, the fuel injector nozzle may be partly blocked.