4-5
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TROUBLESHOOTING
7. Pressure regulator inspection
Check the fuel pressure and record it (page 5-111).
Disconnect the pressure regulator vacuum tube.
Check the fuel pressure.
Is the fuel pressure higher with the vacuum tube disconnected?
YES – GO TO STEP 8.
NO – Faulty pressure regulator.
8. Fuel injector inspection
Inspect the fuel injector (page 5-116).
Is the fuel injector normal?
YES – GO TO STEP 9.
NO – • Repair the open or short circuit fuel injector wire
• Faulty fuel injector
9. IAC valve inspection
Replace the IAC valve with a new one and start the engine.
Engine stalls?
YES – Replace the ECM with a new one and recheck.
NO – Faulty original IAC valve.
ENGINE SOMETIMES MISFIRES OR TENDS TO STALL
1. Spark Test
Perform spark test (page 8-4) at all plugs.
Is there weak or no spark?
YES – Perform ignition system troubleshooting (page 8-3).
NO – GO TO STEP 2.
2. Spark Plug Inspection
Remove and inspect the spark plugs.
Are the spark plugs wet?
YES – • Incorrect spark plug gap
• Incorrect spark plug heat range
• Blockage between the cooling fan cover and cylinder head
• Improper vapor separator float height
NO – GO TO STEP 3.
3. Fuel Flow Inspection
Inspect the fuel flow (page 5-113).
Is the fuel flow within specification?
YES – GO TO STEP 4.
NO – • Clogged fuel strainer (Low pressure side) (page 3-27)
• Clogged water separator (page 5-93)
• Clogged or damaged fuel tube
• Faulty fuel pump (Low pressure side)
• Clogged vapor separator air vent tube or filter
• Clogged fuel feed hose
• Clogged fuel strainer (High pressure side) (page 5-106)
• Faulty vapor separator (page 5-115)
• Faulty fuel pump (high pressure side)
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