Engine Will Not Start, Engine Cold
- Turn ignition on. Connect voltmeter positive lead to glow plug plate and negative lead to good engine ground. Check for 10 or more volts for 1-6 seconds. If voltage exists go to step 5). If no voltage exists, check for 12 volts at battery side of glow plug relay 1. If voltage exists go to step 2). If no voltage exists, circuit is open in wiring harness.
- Move positive voltmeter lead to terminal 1 of control unit. See Fig 1 . Turn ignition switch on. Check for 10 or more volts. If voltage exists go to step 3). If no voltage, ignition switch or wiring harness is defective.
- Turn ignition off. Attach ohmmeter leads to glow plug side of glow plug relay 1 and plug plate. If continuity exists go to step 4). If no continuity, circuit is open in wiring harness.
- Connect voltmeter negative lead to ground. Turn ignition switch on. Approximately 1-6 seconds later, connect positive lead to terminal 2 of the control unit. If voltage exists, glow plug relay 1 is defective. If no voltage, check water temperature sensor and wiring harness used for detection of glow plug temperature. If both sensor and harness are okay, control unit is defective.
- If voltage was observed in step 1), move voltmeter positive lead to terminal 2 of control unit. Turn ignition switch on. Approximately 1-6 seconds later, check for 5-8 volts. Voltage lasts 6 seconds. If voltage exists, go to step 8). If no voltage, check for 12 volts at battery side of glow plug relay 2. If there is no voltage at relay, wiring harness is defective.
- Turn ignition switch off. Connect ohmmeter leads to dropping resistor side of glow relay 2 and to glow plug plate. If continuity exists go to step 7). If no continuity, check resistor and attached harness.
- Connect voltmeter positive lead to terminal 4 of control unit. Connect negative lead to ground. Turn ignition switch on. After switch is on for 7-12 seconds, check for 10 or more volts. If voltage exists, glow plug relay 2 is defective. If no voltage, control unit is defective.
- Move positive voltmeter lead to terminal 4 of control unit. Crank engine. Check for 9 or more volts. If such voltage exists, go to step 9). If no voltage is indicated, crank engine and check for 9 or more volts at terminal 3 of control unit. If voltage exists, control unit is defective. If no voltage, check ignition switch and connecting wiring harness.
- Turn ignition switch off. Connect ohmmeter leads to each glow plug one at a time. Resistance should be less than .1 ohm at 68°F (20°C). If plugs are outside this value, replace them. If plugs are okay, check water temperature sensor for open or short circuit. If temperature sensor is okay go to step 10).
- Check resistance between control unit terminal 9 and glow plug ground. If resistance is excessive, harness mounting screw is loose. If resistance is okay, check fuel system for cause of no start condition.