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HARD START
Checks Action
DEFINITION: The engine cranks OK, but does not start for a long time. The engine does eventually run,
or may start but immediately dies.
Preliminary Checks Make sure the engine’s operator is using the correct starting procedure.
Sensor Checks
Check the Engine Coolant Temperature sensor with the DST. Compare
the engine coolant temperature with the ambient air temperature on a
cold engine. If the coolant temperature reading is more than 10 degrees
greater or less than the ambient air temperature on a cold engine, check
for high resistance in the coolant sensor circuit. Check the cam/crank
sensors.
Check the Throttle Position (TPS) and Foot Pedal Position (FPP) sensor
connections.
Fuel System Checks
Important: A closed LPG manual fuel shut off valve will create a no start
condition.
Check Venturi assembly for proper installation and leakage.
Verify proper operation of the Shut-off solenoid Valves.
Verify proper operation of the system low pressure Regulator.
Check for air intake system leakage between the Throttle Body and Air
Filter Assembly. Check the fuel system pressures. Refer to the Fuel
System Diagnosis.
Ignition System Checks
NOTE: LPG requires higher secondary ignition system voltages for the
equivalent gasoline operating conditions.
Check for the proper ignition voltage output with J 26792 tool or the
equivalent.
Verify that the spark plugs are the correct type and properly gapped.
Check the spark plugs for the following conditions:
Wet plugs (oil fouling).
Cracks.
Wear.
Burned electrodes.
Heavy deposits.
Check for bare or shorted ignition wires.
Check for moisture in the distributor cap.
Check for loose ignition coil connections.
Important:
1. If the engine starts but then immediately stalls, check the cam/crank sen-
sor.
2. Check for improper gap, debris or faulty connections.
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