DIAGNOSE – ENGINE STALLS INTERMITTENTLY
by Kyle McFadden
The engine stalls intermittently. The symptom may be more present after the engine has reached operating temperature or during hot ambient temperatures. The vehicle may restart after a short cool down. When the vehicle is running, it runs normally. If the vehicle misses or idles poorly refer to the “Engine Misses or Idles Poorly” article.
This symptom can be caused by numerous things. If the engine is operating then stalls as if the key was turned off, the cause could be a defective ignition control module or poor connection in the vehicles electrical system.
Diagnosis of this symptom can be difficult due to the number of possible causes. You must determine what is occuring when the engine stalls. The engine could be losing fuel pressure, ignition spark or the computer itself may be defective (ie. the EEC). Once the type of failure has been isolated such as no spark, no fuel or injection pulse, you will need to focus your diagnosis on that particular sub-system. Refer to the applicable section to obtain a working knowledge of each system involved. By understanding each components role you will be able to more accurately troubleshoot the entire system.
PRECAUTIONS, TIPS, and NOTES
Some vehicles are prone to defective ignition control modules. The module may fail when it reaches operating temperature and then becomes functional again after it has cooled off. Use caution when working around hot or rotating engine parts. The ignition system produces extremely high voltage. Use caution when working around the igntion coils and spark plug wires.
has an affinity for Pale Ale and tooling on his 1956 Chevrolet Nomad