Diagnostic Aids

If the cause of an engine cranks but will not run condition has not been found, inspect for the following conditions:

• Hard starting only in cold ambient temperatures. These may cause an intermittent condition that may not occur in the service bay:
  • Fuel heater inoperative-Refer to Fuel Heater Inoperative .
  • Ice blockage at the fuel pickup in the fuel tank-This will be a high vacuum in the supply lines while cranking, and the problem will disappear after the vehicle is brought in the service bay. It may also exhibit a start and stall condition or a starting condition with no acceleration.
• The correct cranking speed is 100 RPM cold and 180 RPM hot.
• A basic engine problem
• Low engine coolant may cause the engine to shut down.