Electrical Issue. Need help...please!

H

HuntleyBill

Junior Member
I run a 6 V alt. on my car. Everything has worked fine until recently when my alt. started putting out OVER 20 amps (as witnessed from my amp meter). I have a 20 amp circuit breaker that I use coming off the starter instead of a fuse some folks usually use. At above idle RPM's, the circuit breaker would trip, the engine would bog down and back fire. When I disconnected the alt, the problem went away.

I replaced the alt. with another one and had the same issue. I removed that alt. and also disconnected ALL accessories I put on the car ie: turn signals, CB, voltage converter etc.

I checked to make sure I had a ground and it seems to be ok.

I put on my original generator and cutout. The amp meter shows a +7 to +8 amp charge. I have driven the car several times over the last couple of days and it has been running great.

Today, on the way back from a picnic the circuit breaker tripped again and the car backfired ......LOUD. I shut it off, disconnected the wiring to the generator and was able to finish driving the last 10 miles home without incident.

Can anyone please help with some suggestions as to what might be causing this? I don't want to just start replacing parts.

Thanks for your help.
 
Bill, As you know, the circuit breaker is tripped because too much current passed through it. That current was probably charge curent produced by the ALT or the generator. That charge current increase was probably caused by a high resistive connection in the charge circuit. Make sure all electrical connections are clean and tight and you might consider adding an additional ground cable from the battery (+) to the transmission case.
 
HuntleyBill said:
I run a 6 V alt. on my car. Everything has worked fine until recently when my alt. started putting out OVER 20 amps (as witnessed from my amp meter). I have a 20 amp circuit breaker that I use coming off the starter instead of a fuse some folks usually use. At above idle RPM's, the circuit breaker would trip, the engine would bog down and back fire. When I disconnected the alt, the problem went away.

I replaced the alt. with another one and had the same issue. I removed that alt. and also disconnected ALL accessories I put on the car ie: turn signals, CB, voltage converter etc.

I checked to make sure I had a ground and it seems to be ok.

I put on my original generator and cutout. The amp meter shows a +7 to +8 amp charge. I have driven the car several times over the last couple of days and it has been running great.

Today, on the way back from a picnic the circuit breaker tripped again and the car backfired ......LOUD. I shut it off, disconnected the wiring to the generator and was able to finish driving the last 10 miles home without incident.

Can anyone please help with some suggestions as to what might be causing this? I don't want to just start replacing parts.

Thanks for your help.
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When you disconnected the alternator and later the generator, did you at that time also disconnect the lighting and horn feeds which are supplied from the alt or gan terminal?
If that is true, I would look for a short in the light or horn circuits.
Rainmaker Ron
 
You've got an intermittant short somewhere--the worst kind. That would blow the breaker, and, if the car is running when it shorts, the engine will keep going around but without spark, pumping raw gas in and out of the cylinders into hot exhaust system, leading to backfire.

I think you can be pretty sure the problem is not in the alternator or generator; they can't all be bad! Jiggle all the wiring you can touch and every component that can jiggle. Do this with and without the ignition on, and with (carefully!) and without the car idling. Hopefully, you'll see the breaker pop. If not, the problem must be inside some component (distributor, coil, steering column, horn ...?) where it's harder to jiggle. Think carefully about anything else you might have changed or done shortly before the problem began.

I don't think it's a bad connection. Those can cause resistance increase and heating, but not increase current flow. I've seen bad fuse connection melt the internal fuse wire connection, wrecking but not blowing the fuse. Similarly, I'm a big fan of an extra grounding wire from battery to drive train, but that can't be your breaker problem, although an intermittant ground could kill the spark and cause the backfiring.

Steve
 
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steve s said:
You've got an intermittant short somewhere--the worst kind. That would blow the breaker, and, if the car is running when it shorts, the engine will keep going around but without spark, pumping raw gas in and out of the cylinders into hot exhaust system, leading to backfire.
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Something is using the current as shown by your amp meter and popped breaker.

A generator or Alt could be designed to put out 1000 amps at 6 volts, but if there is nothing that will use that much current in the circuit nothing will blow out.

My vote is intermittent short, check for repro brake light switch.
 
You have a short somewhere is wat it sounds like. Get a test light from harbor freight or another cheap tool store like it. Disconnect the ground side of the battery and clamp one end of the light to the ground clamp then touch the other end of the light to the battery post. Then Start turning on everything one at a time. When the light, lights up you have found your short. Some times it's more than one. This test light is now apart of my traveling tool box, I don't leave home without it.
 
Logan said:
You have a short somewhere is wat it sounds like. Get a test light from harbor freight or another cheap tool store like it. Disconnect the ground side of the battery and clamp one end of the light to the ground clamp then touch the other end of the light to the battery post. Then Start turning on everything one at a time. When the light, lights up you have found your short. Some times it's more than one. This test light is now apart of my traveling tool box, I don't leave home without it.
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I don't understand how this will work. Won't the test light come on whenever current flows, which will be the case if the headlights, horn, etc. are working properly?

THanks.

Steve
 
No the light will only come one when you turn on the item with the short. It's on the ground side of the battery, not power side.
 
My experience has been when you have an intermittant short, the first place you should look is in the horn! The horn is always hot, unlike the headlights, which are only hot when you turn them on.
 
Patrick L. said:
Steve, you're correct.. A test light used in the connection will show any draw on that circuit..
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Ok, yall were right. Its been so long sinc i used it i had forgotten lol. But i just checked harbor freight and the one i use is 3.99. They come in real handy. we were on a tour one time and ken davis pulled one of these out, for a car having problems like yours where it charges to much. And he found 3 shorts, one being the dome light.
 
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