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Home >> Cadillac >> 2006 >> STS Base, 3.6 7, RWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 5 (Engine Control System - 4.6L (LH2) - Troubleshooting & Diagnosis) >> Hard Start

Hard Start

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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
Fuel System
Ignition System
  • Inspect for proper ignition voltage output with the J 26792  Spark Tester. Refer to Electronic Ignition (EI) System Diagnosis .
  • Remove the spark plugs and inspect for the following conditions:
    • Correct heat range
    • Wet plugs
    • Cracks
    • Wear
    • Improper gap
    • Burned electrodes
    • Heavy deposits

      Refer to Spark Plug Inspection .

  • Determine the cause of the conditions before replacing the spark plugs.
  • Inspect for loose ignition coil grounds.
  • Inspect the ignition coils for cracks or carbon tracking.
  • Soak the secondary ignition with water may help locate an intermittent problem. Ignition voltage will arc to ground when a secondary component is faulty.
Engine Mechanical Inspect for the following conditions:
Inspect for excessive crankshaft endplay that will cause the crankshaft position (CKP) sensor reluctor wheel to move out of alignment with the CKP sensor. Refer to Crankshaft and Bearing Cleaning and Inspection in Engine Mechanical. This could result in any of the following conditions:
  • A no start
  • A start and stall
  • Erratic performance
Additional
  • Inspect for a restricted exhaust. Refer to Restricted Exhaust in Engine Exhaust.
  • Inspect the air intake ducts for being collapsed, damaged, loose, improperly installed, or leaking, especially between the mass air flow (MAF) sensor and the throttle body.