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Electrical System

Troubleshooting the Starter and Vehicle Starting Circuit

Note: The following instructions listed below consist of general information for troubleshooting the starter and vehicle starting circuit. Refer to the Original Equipment Manufacturer's service manual for specific information pertaining to your vehicle.

 

FIRST, IF AVAILABLE, CONDUCT A STARTER PERFORMANCE TEST WITH AN ALTERNATOR/STARTER TEST BENCH.

  • If the starter is not performing, it is important to resolve any additional vehicle side problem(s) in the starting circuit that may have effected the starter.

  • If the starter meets the manufacturer's specifications, refer to the manufacturer's service manual to inspect the vehicle starting circuit and to identify the problem(s) and possible corrective action(s).
  • If an alternator/starter test bench is not available, identifying the customer's true starting circuit problem is important to prevent unnecessary starter replacement. Troubleshoot the system with the following questions:

1. DOES THE STARTER TURN THE ENGINE TOO SLOWLY? IF THE STARTER TURNS THE ENGINE SLOWLY, VERIFY PROPER BATTERY CHARGE, BATTERY CABLES, IGNITION TIMING, ENGINE OIL AND ENGINE MODIFICATIONS.

  • Is the battery fully charged (12.6 volts) and are the battery cables and terminals in good condition?

  • If the engine has been modified, including increased compression ratio, it could affect the starter's ability to turn the engine.

  • Improper engine timing (usually advanced) and excessive engine oil viscosity (usually higher) can also affect the starter's performance.

2. DOES THE STARTER FAIL TO CRANK THE ENGINE?

  • If the starter fails to crank the engine, check the battery and battery cables and terminals. Be sure both ends of the battery cables are checked for proper connection and are clean.

3. DOES THE STARTER TRY TO TURN THE ENGINE AND THEN SPINS FREE?

  • If the starter tries to turn the engine but just spins, check the flywheel ring gear or flex plate for excessive wear and missing or damaged teeth. A failed starter drive could produce similar symptoms.

  • The flywheel teeth can be inspected through the starter access or mounting opening. Check four cylinder engines, two positions, 180 degrees apart, six cylinder engines, two positions, 120 degrees apart and eight cylinder engines four positions, 90 degrees apart. These are the areas to find excessive wear.

4. DOES THE STARTER CLICK WHEN TRYING TO START THE ENGINE? HAS THE GROUND CIRCUIT BETWEEN THE BATTERY AND THE ENGINE BEEN CHECKED FOR HIGH RESISTANCE? HAVE THE BATTERY CABLES AND TERMINALS BEEN CHECKED FOR DAMAGE, WEAR, CORROSION AND LOOSE CONNECTIONS?

  • If the solenoid or relay clicks and the starter does not turn, the problem could be a loose connection or damaged wires.
  • Check the voltage drop of the battery cables for high resistance. Refer to the manufacturer's service manual.

5. IS THERE A CLATTERING SOUND WHEN TRYING TO START THE ENGINE?

  • A clattering sound when trying to start the engine could be caused by a bad flywheel/ring gear, an inoperable starter solenoid or low battery voltage.
  • The battery must be fully charged (12.6 volts) and the battery cables and terminals in good condition?

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