Questions and Answers

Motor Home Over Charging Q. Thanks for the info on my 1992 Ford Motor home hard starting problem. Here's one more from a friend of mine: Motor home is 1980 with a Dodge 440 engine and 63M miles on it. It appears that while he was driving, the Motor home quit, the battery exploded, the radio fried and the voltage gage is B/O.

The smoke coming out of the vents was also interesting.

With the help of a mechanic he has changed out the alternator, battery, coil, voltage regulator, ignition module, isolator, starter relay, and a new ground strap to the regulator.

They were able to get the engine running but it is putting out 19-20 volts to the battery. The mechanic is talking of rebuilding the distributor next(?).

Question: Why the 19 volts since the regulator has been changed out. Any ideas? He's close to just walking away from it.

A. Rebuilding the distributor may be a good idea in light of the over voltage condition, but it will not fix the problem.

The only thing that will cause an alternator to overcharge is a bad voltage regulator. I have seen alternators run wild and put out over 60 volts. Now since the voltage regulator was replaced and assuming it's good, I would examine the wire from the field terminal of the alternator to the field terminal of the voltage regulator. If that wire is shorted, that will make the alternator over charge. If the voltage regulator is sensing an open circuit it will cause an over charge.

Unplug the voltage regulator and with the key on engine off check for voltage at the Blue and Green wires. If not, then you have a wiring problem. If you do, the voltage regulator is no good.

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