DIAGNOSE ENGINE CRANKS FAST BUT DOESN’T START
by Kyle McFadden
The engine cranks over at normal speed but fails to start.
A no-start condition can be caused by numerous items. If the vehicle is eqiupped with a timing belt and the engine has over 60,000 miles on it and it has never been serviced, it could be broken. This is especially true if the vehicle stalled while driving and will not restart. A defect in any of the vehicles electronics can cause the same symptom. A defective ignition control module or distributor pick-up, ranks as one of the highest probabilities.
A diagnosis should start with an inspection of the vehicles fuses. Refer to the fuse block placard and owners manual for fuse ratings and designations. An engine that is cranking over unevenly or abnormally fast, is a key indicator of an engine mechanical failure. A compression check should be performed to detect a mechanical failure. If the engine is in proper mechanical order, the ignition system should be inspected for spark while the engine is cranked. A spark tester is available at most auto parts stores. If there is no spark, the ignition control module, distributor pick-up or crankshaft sensor should be tested. A visual inspection of the distributor cap and rotor (if so equipped) should be performed. If spark and proper engine compression are present, a diagnosis of the fuel system will be necessary. Fuel pressure and injector pulse should be tested. You will need to determine if the electric fuel pump is operating, the injectors are firing and there is adequate fuel pressure. You should consult a vehicle specific repair manual for diagnosis of the specific fuel system components on your vehicle.
PRECAUTIONS, TIPS, and NOTES
Use caution when working around hot or rotating engine components. When test equipment is used, always refer to the manufacturers instructions for proper usage. Always disable the ignition system prior to performing a compression test. This is usually done by connecting the spark plug wires or coil wire to an engine ground. Refer to a vehicle specific repair manual for instructions on how to disable the ignition system.
has an affinity for Pale Ale and tooling on his 1956 Chevrolet Nomad