Why is it sticking?
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Joined: Apr 2004
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From: Georgia
Why is it sticking?
My dad has a 93 ranger w/4.0 liter. The other day as he was shutting it off when he got to my house, the amp meter gauge pegged out and got stuck. He hit the dash and it went back to its normal switched off position. When I asked him about it he said it always does it when he shuts engine off. What could be causing this?
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Joined: Jan 2004
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From: SW Va
Has he installed an aftermarket "Amp" meter, or are you talking about the in-dash voltmeter????
If it's the in dash voltmeter thats pegging on shutdown, I'd maybe suspect something is amiss with the alernators voltage regulator.
So why not run this puppy by your favorite autoparts store, for a no cost, in vehicle, electrical system, check-up, with their portable electrical system tester.
It'll proerly load test the alternators output & check it's voltage regulation.
If the voltage spike on shutdown is real, it could eventually cause some other electrical mischief imo.
If it's the in dash voltmeter thats pegging on shutdown, I'd maybe suspect something is amiss with the alernators voltage regulator.
So why not run this puppy by your favorite autoparts store, for a no cost, in vehicle, electrical system, check-up, with their portable electrical system tester.
It'll proerly load test the alternators output & check it's voltage regulation.
If the voltage spike on shutdown is real, it could eventually cause some other electrical mischief imo.
Thread Starter
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Posting Guru
Joined: Apr 2004
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From: Georgia
Yes it is the factory gauge in the dash. I do most of my own maintenance and have done so for years but never have liked working with electrical gremlins. My question back to you pawpaw is why would it spike at shutdown if it were a bad regulator? It seems to me that a bad regulator would spike the gauge at start up.
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Joined: Jan 2004
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From: SW Va
Well with the engine running & the alternator outputting & hopefully the votage regulator doing it's thing, seems to me the only thing in this circuit thats capable of causing a voltage spike high enough to slam the voltmeter is the alternator, after the regulator has lost control for an instant, on shutdown.
Maybe the problem lies in the ignition switch's contacts, or maybe it's something in the regulator that doesn't like it when it's switched off.
An electrical system check up should tattle on the culprit.
If you have a fast acting digitial voltmeter, you might be able to measure the spike.
At startup, there is no output from the alternator, until current begins to flow through the field & the engine turns the alternator over fast enough for the stator to begin it's output, so the regulator has plenty of time to get that feedback, react & keep things under control, so it doesn't slam the voltmeter.
Just some thoughts to ponder.
Maybe the problem lies in the ignition switch's contacts, or maybe it's something in the regulator that doesn't like it when it's switched off.
An electrical system check up should tattle on the culprit.
If you have a fast acting digitial voltmeter, you might be able to measure the spike.
At startup, there is no output from the alternator, until current begins to flow through the field & the engine turns the alternator over fast enough for the stator to begin it's output, so the regulator has plenty of time to get that feedback, react & keep things under control, so it doesn't slam the voltmeter.
Just some thoughts to ponder.
