No Engine Cold Start
Perform these diagnostic procedures if engine does not start when cold; "GLOW PLUG" light may or may not come on. Before proceeding, check fuel system to ensure it is okay. Ensure battery voltage is 12.4 volts or more with ignition switch in the "OFF" position. Check cranking speed is at least 100 RPM.
- With the ignition switch off, use a voltmeter to measure the voltage at the battery stud (single wire) on the glow plug. See Fig 1. If no voltage is present, repair battery to glow plug controller circuit.
- If no voltage is present in step 1), disconnect the harness from all glow plugs. Use an ohmmeter to measure continuity between the glow plug terminals and engine block. Replace glow plug if measurement is greater than 2 ohms. Reconnect all glow plugs before continuing with diagnosis.
- If voltage is present in step 1), turn engine ignition switch to "OFF" position and measure voltage at glow plug feed stud (twin lead) on glow plug controller. If battery voltage is present, relay contacts are shorted. Replace controller and all glow plugs.
- With all glow plugs reconnected, place ignition switch in "RUN" position. Remove controller connector and check voltage at harness connector terminal "D". See Fig 1.
- If no voltage is present, repair open in ignition feed circuit to controller. If voltage is present, measure continuity between terminal "E" of the connector and the engine block (ground). If measurement is greater than one ohm, repair the ground circuit to the controller.
- With ground circuit working properly in step 4), measure continuity between terminals "C" and "E" of the connector. See Fig 1. If reading is greater than 2 ohms, go to step 6). If reading is less than 2 ohms, go to step 8).
- If reading in step 5) is greater than 2 ohms, remove the connector from the temperature inhibit switch and measure the continuity between the two terminals on the switch. Switch is open above 125°F (51.5°C). If reading is less than one ohm, repair the glow plug circuit to the controller. If reading is greater than one ohm, replace temperature inhibit switch and return to step 6).
- If reading in step 5) is less than 2 ohms, reconnect controller harness connector and ensure complete engagement. Connector locking latch should click over controller locking tab. With controller connector harness correctly connected, measure voltage at glow plug feed stud (twin lead) on glow plug controller, while turning ignition switch from "OFF" position to "RUN" position.
- If no voltage is present, replace glow plug controller. If battery voltage is present, measure voltage at any one glow plug harness connector when turning ignition switch from "OFF" to "RUN" position. Test both right and left banks.
- If no voltage is present in step 8), repair glow plug feed circuit to glow plugs. If battery voltage is present and instrument panel "GLOW PLUG" lamp does not come on, locate and repair bulb or circuit.