Diagnostic Aids

Water or foreign material in fuel can cause a no-start or lack of power condition. Low fuel pressure, restricted fuel filter or fuel injectors may also cause a no start condition. Refer to TEST A1-5  under CIRCUIT TESTS for fuel injector circuit test. Check power supply to PCM.

There may be fuel spray at fuel injectors, but it may be inadequate to start engine. If fuel injectors and circuits are okay, there may be a partly blocked or restricted injector nozzle. Refer to TEST A1-7A  under CIRCUIT TESTS for circuit opening relay circuit test.

An intermittent malfunction may be caused by a poor connection, rubbed through wire insulation or a wire broken inside insulation. Check for an open or loose or disconnected terminals.

1. Ensure PCM ground connections are clean and tight. See appropriate wiring diagram in the WIRING DIAGRAMS article. Check for blown IGN or EFI F-HTR fuses. Ensure there is adequate fuel. If specified components are okay, go to next step. If specified components are not okay, perform repairs as necessary. If repair was necessary, go to step 11).
2. Relieve fuel system pressure. See FUEL SYSTEM PRESSURE RELEASE  under FUEL SYSTEM. Install fuel pressure gauge. Turn ignition on. Fuel pump will run for about 3 seconds. Cycle ignition on and off until maximum fuel pressure is indicated. If fuel pressure is 38-44 psi (2.7-3.1 kg/cm² ), go to next step. If fuel pressure is not as specified, go to TEST A1-7A  under CIRCUIT TESTS.
3. Turn ignition off. Disconnect fuel pressure gauge. Disconnect all 4 injector connectors. Install fuel injector tester (noid-light J-34730-2B) to No. 1 fuel injector harness connector. Crank engine and observe noid-light. Repeat for each injector. If noid-light blinks for each injector, go to next step. If noid-light does not blink for each injector, go to step 6).
4. Go to CIRCUIT TEST A1-7C  for fuel injector performance tests. Repair as necessary. If repair was necessary, go to step 11). If fuel injectors are okay, go to next step.
5. Test fuel for contamination. If contamination is present, clean fuel system. If repair was necessary, go to step 11). If fuel system is okay, check for the following:
   • Incorrect valve timing.
   • Worn or incorrect camshaft.
   • Leaking or sticky valves or rings.
   • Excessive valve deposits.
   • Loose or worn rocker arms.
   • Weak valve springs.
   • Leaking head gasket.

   Repair as necessary. If repair was necessary, go to step 11). If no problems are found, see the TESTS W/O CODES article.

6. If noid-light remains on for one or more injectors, go to next step. If noid-light does not remain on for any injector, go to step 8).
7. Check for short to ground on affected fuel injector harness connector. Repair as necessary. If injector harnesses are okay, replace PCM. If repair was necessary, go to step 11).
8. Remove noid-light. Turn ignition on. Using a test light connected to ground, probe faulty fuel injector harness connector terminal No. 2 (Black wire). Repeat for each faulty injector. If test light illuminates, go to next step. If test light does not illuminate, check for open or short in power feed circuit (Black/Orange wire, changes to Black wire at injector) between ignition switch and injector. Repair as necessary. If power feed circuit is okay, replace ignition switch. If repair was necessary, go to step 11).
9. Using a test light connected to battery voltage, probe faulty fuel injector harness connector terminal No. 1. Crank engine and observe test light. Repeat for each faulty injector. If test light blinks for each test, see DIAGNOSTIC AIDS. If test light does not blink, go to next step.
10. Check for open in fuel injector control circuit. See the CONTROL CIRCUIT IDENTIFICATION  table. Repair as necessary. If injector control circuit is okay, replace PCM. Go to next step.
11. Using scan tool, clear Diagnostic Trouble Codes (DTCs). Attempt to start engine. If engine starts and runs, allow engine to idle until normal operating temperature is reached. Using scan tool, check for DTCs. If any DTCs reset, go to appropriate CIRCUIT TEST in the TESTS W/CODES article. If no DTCs reset, system is okay. If engine does not start, return to step 1).