Chart A-5 Fuel Injector Circuit Check

Diagnostic Chart - 1 of 3:

Diagnostic Chart - 2 of 3:

Diagnostic Chart - 3 of 3:

Electrical Schematic:

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 each combustion chamber. 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 3 seconds.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
(Part 1 of 3)
1. Checks fuel pump operation with ignition switch in the "ON" position.
2. This checks for an open in BLU/BLK wires between fuel Injectors and the main relay.
3. Checks for an open or poor connection in ground control wires between fuel injectors and ECM.
4. This sets up the fuel injector tester J 39021.
5. This checks the engine coolant temperature for the proper test conditions.
6. This checks for faulty fuel injectors when the engine coolant temperature is between 10° - 35°C (50° - 90°F).
(Part 2 of 3)
7. This checks for faulty fuel injectors when the engine coolant temperature is above or below 10° - 35°C (50° - 90°F).
(Part 3 of 3)
8. This checks for proper fuel pressure prior to testing the injectors for proper balance.
9. This tests the injectors for fuel pressure drop.
10. This test checks for faulty fuel injectors(s)

DIAGNOSTIC AIDS
An intermittent malfunction may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation. Inspect harness connector for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals and poor terminal-to-wire connections before component replacement.