1251 to 1256 - Fuel Injectors

Fuel injectors, checking:

Electrical Test:

NOTE: This is an electrical test. it does not check spray patterns or fuel supply to the injectors.

- Remove the plastic engine cover from the top of the engine.

- Pry off the cover from the injector wiring duct to access the wiring to the injectors. Connect a digital voltmeter to an injector connector. See Fig. 13.

CAUTION: Use only a digital voltmeter or an LED injector tester. Use of an analog VOM or incandescent test light may damage the control module.

- Operate the starter or run the engine and check that pulsed voltage is present. (approx. 0.3-1.0 VDC).

- If the light doesn't flash or there is no voltage, check for power to the injector. There should be battery voltage (+) at the red/white wire of each injector connector with the ignition key on. If not, check the DME main relay and the wiring to the injector.

NOTE: If there is positive (+) battery voltage but there was no response at voltmeter, check the wire(s) from the ECM to the injectors. If no wiring faults can be found, the pulsed ground signal from the control module may be missing. Check the outputs from the ECM.

- If power is present, unplug the injector connectors and check the injector resistance. Replace the injector if the resistance is incorrect.

Injector coil Resistance: 16 ohms at 68°F (20°C).

NOTE: Injector resistance will vary depending on temperature. In general, the range should be between 10 and 20 ohms.

- If no faults are found up to this point, check the pulse- time regulation function of the control module with the engine cold. Peel back the rubber boot from the injector connector and connect a voltmeter to the wires in the connector. Start the engine. Check that the voltage decreases as the engine warms up.

- If any faults are found, check the ECM inputs and outputs as described later.