Table A1-5 Fuel Injector Circuit Check (Engine No-Start)

Diagnostic Chart:

Wiring Diagram:

Circuit Description

When the solenoid coil of the fuel injector is energized by the Powertrain Control Module (PCM), 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 PCM is receiving ignition reference pulses. If the PCM does not receive any reference pulses, the fuel pump will stop after 2 seconds.

Diagnostic Aids

There may be fuel spray at the fuel injector, but it may not be enough to start the engine. Normal fuel injector resistance is 0.5 - 1.5 ohms at 20°C (68°F). If both the fuel injector and the circuit are OK, the fuel injector nozzle may be partly blocked.

Check the fuel injector resistor for poor connections or high resistance. Normal fuel injector resistor resistance is 1.9 - 2.8 ohms at 20°C (68°F).

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

Test Description

The numbers below refer to the step numbers in the Diagnostic Table.

1. The Powertrain OBD System Check prompts the technician to complete some basic checks and store the freeze frame data on the scan tool if applicable. This creates an electronic copy of the data taken when the fault occurred. The information is then stored in the scan tool for later reference.

2. Checks to see if the PCM is controlling the fuel injector signals.

3. Checks the fuel injector for correct resistance.

5. Checks for voltage at fuel injector.

5. Checks for an open or short to ground in fuel injector control circuit, a faulty PCM or for a faulty fuel injector.

13. Checks for an open in the YEL wire, an open in the ignition feed circuit or for a faulty fuel injector resistor.