Diagnosis & Repair
- Inspect spark plugs and ignition system. See appropriate BASIC TESTING article. Repair as necessary. If ignition system is okay, ensure ignition is off.
- Access ECM harness connectors behind glove box. Turn ignition on. Using DVOM, backprobe ECM connector and measure voltage between ground and injector terminals at ECM E14 connector. See IDENTIFYING INJECTOR TERMINALS table. If voltage is 9-14 volts for each circuit, go to step 4). If voltage is not 9-14 volts, go to next step.IDENTIFYING INJECTOR TERMINALS
Injector No. Terminal No. (1) Wire Color 1 10 Yellow 2 9 Black/Yellow 3 8 Blue 4 7 Red 5 6 Blue/White 6 5 Red/White 7 16 Yellow/Red 8 15 Black/Blue (1) Terminals are located in ECM E14 connector. - Disconnect injector of misfiring cylinder. Using ohmmeter, measure resistance between injector terminals. With injector temperature at 68°F (20°C), if resistance is 13.4-14.2 ohms, inspect circuits between ECM and injector for open or short circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. If resistance is not 13.4-14.2 ohms, replace injector.
- Inspect fuel pressure. See BASIC TESTING article. Repair as necessary. If fuel pressure is okay, inspect fuel injector performance. See SYSTEM/COMPONENT TESTS article. Replace as necessary.
- If all injectors are okay, inspect EGR system. See appropriate SYSTEM/COMPONENT TESTS article. Repair as necessary. If EGR system is okay, inspect MAF sensor and ECT sensor. See appropriate SYSTEM/COMPONENT TESTS article. Replace as necessary. If both components are okay, check engine compression, valve clearance and valve timing. See BASIC TESTING article. Repair as necessary.