TOHATSU BFT250A Service Manual page 98

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TROUBLESHOOTING
4. Pressure regulator inspection
Inspect the fuel pressure and record it (page 5-111).
Disconnect the pressure regulator vacuum tube.
Inspect the fuel pressure.
Is the fuel pressure higher with the vacuum tube disconnected?
YES
NO
5. Fuel injector inspection
Inspect the fuel injector (page 5-116).
Is the fuel injector normal?
YES
NO
6. IAC valve inspection
Replace the IAC valve with a new one and start the engine.
Engine sometimes misfires or tends to stall?
YES
NO
ENGINE DOES NOT RUN SMOOTHLY
ENGINE SPEED IS HIGHER THAN THE SPECIFIED IDLE SPEED AFTER WARMING UP
1. Alert system inspection
Turn the combination switch ON.
Check the warning buzzer sound.
Does the warning buzzer sound twice and then keep sounding?
YES
NO
2. Engine idle speed inspection
Adjust by turning the idle adjusting screw in or out.
Is the engine speed normal?
YES
NO
3. Pressure regulator inspection
Inspect the fuel pressure and record it (page 5-111).
Disconnect the pressure regulator vacuum tube.
Inspect the fuel pressure.
Is the fuel pressure higher with the vacuum tube disconnected?
YES
NO
4. IAC valve inspection
Replace the IAC valve with a new one and start the engine.
Is the engine idle speed normal?
YES
NO
4-6
– GO TO STEP 5.
– Faulty pressure regulator.
– GO TO STEP 6.
– • Repair the open or short circuit in the fuel injection wire
• Faulty fuel injector
– Replace the ECM with a new one and recheck.
– Faulty original IAC valve.
– Perform alert/warning system troubleshooting (page 4-18).
– GO TO STEP 2.
– Improper idle adjusting screw.
– GO TO STEP 3.
– GO TO STEP 4.
– Faulty pressure regulator.
– Faulty original IAC valve.
– GO TO STEP 5.