Overcharging System

freddrew · December 02, 2008, 07:27:47 PM

My 46 Ford pickup developed a new problem a couple of weeks ago. The lights get extremely bright and the voltmeter reads over 16. Occasionally the lights go back to normal and the voltmeter will read between 12.5 and 13. I have cleaned all contacts and replaced the battery, alternator, voltage regulator and the field wire. I swapped out a known good voltage regulator and it made no difference. The battery and alternator were tested and found to be good. None of these things made any change. Most of the time, the system is charging over 16 volts and maintains that with all the electrical devices drawing maximum current. I removed all cables and wires, cleaned them and all were tight when removed. Help!!!

Has anyone had a similar problem and if so, what is the cause and cure? Let me know any suggestions. I am running out of things to try. The driveline is 1987 Chrysler 318 and the wiring hasn't changed since building 5 years ago..

Fred

Learpilot · December 02, 2008, 07:39:57 PM

Quote from: "freddrew"My 46 Ford pickup developed a new problem a couple of weeks ago. The lights get extremely bright and the voltmeter reads over 16. Occasionally the lights go back to normal and the voltmeter will read between 12.5 and 13. I have cleaned all contacts and replaced the battery, alternator, voltage regulator and the field wire. I swapped out a known good voltage regulator and it made no difference. The battery and alternator were tested and found to be good. None of these things made any change. Most of the time, the system is charging over 16 volts and maintains that with all the electrical devices drawing maximum current. I removed all cables and wires, cleaned them and all were tight when removed. Help!!!

Has anyone had a similar problem and if so, what is the cause and cure? Let me know any suggestions. I am running out of things to try. The driveline is 1987 Chrysler 318 and the wiring hasn't changed since building 5 years ago..

Fred

I have never had voltage get that high ,but I did get a great voltage drop when I turned on the headlights. The cure was to put a ground from the engine to the body and from the engine to the frame with #0 battery cable.

wayne petty · December 02, 2008, 09:40:50 PM

fred.... do you have the chrysler charging system also....

i agree about the grounds...

got a digital volt meter?

set it to 20 volts dc.. with the engine running.. check the voltage between the negative battery terminal and the engine block... should be less than 0.5 volts... and again from the negative battery terminal to the body.... you should see less than 0.4 volts with the head lights on... these are voltage drop tests... takes about a minute to do... if that long... it tells if you have good grounds....

i have had a later model mopar alternator go into overcharge by its self... but it was a odd failure... one of the rotor wires that fed under the bearing would only short out at speeds above idle... caused it to max charge.. made me crazy...

so a little more info about your system... we can describe how it works so you can test things...

Carnut · December 02, 2008, 10:15:26 PM

I know you said you replaced the regulator, but my 61 Chrysler had the exact same symptoms and replacing my regulator cured my problem perfectly.

Crosley.In.AZ · December 02, 2008, 10:50:55 PM

Neighbor had an alt and regulator on his Duster take a dump and over power the system.. it burned out both head lights and some dash bulbs. First and only time I've seen that

C9 · December 03, 2008, 08:36:49 AM

My 59 Ranchero overcharged with a brand new regulator.
Another new regulator solved the problem.

My 77 Ford F-250 4x4 did somewhat the same thing.

Even though the alternator terminals seemed tight where the wire terminals connected, one of them - think it was the "S" (stator) wire - had spun the nut under the terminal and it would move around and short out.

Crazy as it sounds, and it was driving me crazy, I installed a rheostat in the stator wire, mounted the rheostat in the dash and controlled the charge rate with that.

Once I found and rectified the loose terminal, problem cured.

Jokester · December 03, 2008, 11:05:21 AM

I had a Chrysler system once that would occasionally go to full charge. A new regulator would fix it for 3 or 4 months until it did it again. After replacing it 6 times I found out the ammeter was bad.

my 2 cents

.bjb

freddrew · December 05, 2008, 09:04:07 PM

I didn't get the Voltmeter out of the dash today. It's -7 degrees and I have to work on it outside. Yesterday the system woarked properly on both 10 mile trips I made. Today it also worked properly. If we get a warmer day, I'll pull the gauge.

Fred

phat46 · December 05, 2008, 10:01:22 PM

Quote from: "freddrew"If we get a warmer day, I'll pull the gauge.

Fred

So....you're not gonna fix it till April?

?

'Sposed to get colder this weekend Fred.

wayne petty · December 05, 2008, 10:08:19 PM

WAIT A SECOND.... when we are talking about measuring the voltage between points on the battery cables, block, body, frame....

we are talking about doing it with a hand held digital volt ohm meter... not the gauge out of your dashboard...

digital volt meters start at about 3 bucks on sale at harbor freight...

a good one is 20 to 25 bucks... one that does a lot of extra stuff on cars is about 100 bucks...

to do simple diagnosis... a 5 to 25 buck meter is all that is needed...

i tryed to search carquest... and canadian tire... i really don't know what else it there...

you need a cheep digital volt meter that will read DC volts.. AC volts, OHMS.. hopefully ac and dc amps...

so unless i have missed something... and i do... leave you dash gauge in place.. it really is not the right tool to do voltage drop tests...[/list]

Overcharging System

Learpilot