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Hard Start

Hard Start

Inspection/Test Action
DEFINITION: Engine cranks OK, but does not start for a long time. Does eventually run, or may start but immediately dies.
Preliminary
Sensor/System
  • Verify that the engine coolant temperature (ECT) sensor is not shifted in value. Connect a scan tool. Compare the engine coolant temperature to the intake air temperature (IAT) on a cold engine. The ECT and IAT sensor values should be within +/- 3°C (5°F) of each other. If the ECT sensor is out of range with the IAT sensor, measure the resistance of the ECT sensor. Refer to Temperature vs Resistance for resistance specifications.
  • IMPORTANT: The embossed arrows on the MAF sensor indicate the direction of the intake air flow. The arrows must point toward the engine.
  • Inspect the mass air flow (MAF) sensor installation. A MAF sensor that is incorrectly installed may cause a hard start. Install the MAF in the proper direction. Refer to Mass Air Flow (MAF)/Intake Air Temperature (IAT) Sensor Replacement .
  • Inspect the camshaft position (CMP) sensor for proper mounting and/or a bad connection. An extended crank occurs if the PCM does not receive a CMP signal.
Fuel System
Ignition System
  • Verify that both fuel injector fuses are not open. An open fuel injector fuse causes 4 ignition coils and 4 fuel injectors not to operate. Inspect the ignition coil circuits and the fuel injector circuits for an intermittent short to ground. Refer to Circuit Testing in Wiring Systems. Replace the fuse.
  • Inspect for proper ignition voltage output with the J 26792  Spark Tester. See Special Tools . Refer to Electronic Ignition (EI) System Diagnosis .
  • Remove the spark plugs and inspect for the following:
    • Correct heat range
    • Wet plugs
    • Cracks
    • Wear
    • Improper gap
    • Burned electrodes
    • Heavy deposits
Refer to Spark Plug Inspection .
Engine Mechanical Inspect for the following conditions: