ECT Between 10-35 Degrees C (50-95 Degrees F)

Diagnostic Chart:

Schematic:

CIRCUIT DESCRIPTION
The injector coil test is performed to diagnose a faulty fuel injector. The injector coil test makes use of the Fuel Injector Test J 39021. The tester is used to supply current to each fuel injector. This allows injector resistance measurement by using a Digital Multi-Meter (DMM) to measure voltage drop.

DIAGNOSTIC AIDS
Low voltage indicates a high resistance at an injector's coil.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.

CAUTION: Wrap a shop towel around the fuel pressure connection in order to reduce the risk of fire and personal injury. The towel will absorb any fuel leakage that occurs during the connection of the fuel pressure gauge. Place the towel in an approved container when the connection of the fuel pressure gauge is complete.

2. The engine coolant temperature affects the ability of the fuel injector tester to detect a faulty fuel injector. If the engine coolant temperature is NOT between 10°C and 35°C (50°F and 95°F), go to Fuel Injector Coil Test - Engine Coolant Temperature (ECT) Outside 10-35 Degrees C (50-95 Degrees F). Component Tests and General Diagnostics
3. The first second of the voltage displayed by the DMM may be inaccurate due to the initial current surge, therefore, record the lowest voltage displayed by the DMM after the first second of the test. The voltage displayed by the DMM should be within the specified range (refer to the Example). The voltage displayed by the DMM may increase throughout the test as the fuel injector windings warm and the resistance of the fuel injector windings changes. An erratic voltage reading (large fluctuations in voltage that do not stabilize) indicates an intermittent connection within the fuel injector.