TOHATSU BFT250A Service Manual page 97

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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
NO
8. Fuel injector inspection
Inspect the fuel injector (page 5-116).
Is the fuel injector normal?
YES
NO
9. IAC valve inspection
Replace the IAC valve with a new one and start the engine.
Engine stalls?
YES
NO
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
NO
2. Spark Plug Inspection
Remove and inspect the spark plugs.
Are the spark plugs wet?
YES
NO
3. Fuel Flow Inspection
Inspect the fuel flow (page 5-113).
Is the fuel flow within specification?
YES
NO
– GO TO STEP 8.
– Faulty pressure regulator.
– GO TO STEP 9.
– • Repair the open or short circuit fuel injector wire
• Faulty fuel injector
– Replace the ECM with a new one and recheck.
– Faulty original IAC valve.
– Perform ignition system troubleshooting (page 8-3).
– GO TO STEP 2.
– • Incorrect spark plug gap
• Incorrect spark plug heat range
• Blockage between the cooling fan cover and cylinder head
• Improper vapor separator float height
– GO TO STEP 3.
– GO TO STEP 4.
– • 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)
TROUBLESHOOTING
4-5