Car engine shuts off by itself, now it won't start!!
Although it would be an unusual problem, I would have the alternator checked and even buy a low-cost digital voltmeter from Radio Shack or an auto parts store; these cost under $20 and would let you monitor the on board voltage to watch for glitches your dashboard meter will miss since it is heavily 'damped' to prevent the needle from bouncing around while traveling rough roads.
Having one of these multimeters will also let you monitor the battery voltage while trying to start and verify correct charge voltage from the alternator while the engine is running; it should be somewhere between 13-14.7 volts depending on the battery's state of charge. A healthy battery, when charged, will settle at around 12.6 volts after sitting for a while with the engine off. They will measure a little higher right after turning the engine off.
Our alternators have high-current diodes internally and one of these (there are 3-6 diodes) may be shorting at random badly enough to drag the 12V system down far enough to cause the computer and/or the ignition to fail momentarily.
You should also remove the battery clamps, ALWAYS(!) negative (ground) first, and use a battery terminal brush to clean the terminals of the battery and the inside of the clamps.
Once your hands are dirty, remove the other ends of the battery cables too and using a steel brush, scrub the corrosion from those ends too.
The ground cable will go either to the engine block, then chassis or vice versa and both of their terminations should be cleaned.
I've had these diodes die (short) so that they drained the battery in only a brief time.
May 04, 2009 |
1991 Chevrolet Lumina