Electrical Question: What's First?

[Don Jordan]

The bad news is I'm plagued with problems - the good news they're little problems. The car runs great. I had a little problem with the fuel pump (electrical) now I have a new one. Started the car up - sounds great. Problem: no movement in the amp gauge. So what are we looking at? Coil? Voltage regulator? Generator? Amp gauge? I'm going to take it to Tucson next month and I'd hate to have it crap out in the middle of the desert. Any hints will be appreciated. Tomorrow it's getting the once over.

[_shel_ny]

...

Edited April 1, 2013 by shel_bizzy_48

[Tom Skinner]

Don,

Starting point:

Look for loose wire at Amp Gauge.

Continue to look for loose wires, particularly at the Generator and Voltage Regulator after the Amp Gauge.

Run a test of the Generator and Regulator .- to see if they are working.

Use a Service Manual to run tests.

I think I just saw a post here on the Forum yesterday on how to test a Generator?

Tom

[greg g]

with the car off turn on  the headlights to highbeam does it move to negative?  Now step on the brakes, does it move further?  With the car running and with a new battery or fully charged battery the gauge should not be showing much movement.

[suntennis]

The tests Greg G suggests will show that the amp Gage works. Charge the battery, then check the voltage and it should be without anything drawing power 6.1 to 6.4 volts. Run the engine around 900 rpm and check to see that the voltage is greater than just battery voltage. If the charging voltage is more than battery voltage, then the charging system is good and you are good to go. If the voltage at 900rpm is the same as the battery voltage, then there is a problem with the charging system.

[Don Jordan]

Okay - I know this is important but I don't know how to interpret the findings. I had the car running and I pulled the negative wire off the battery and the car died. I should know this from Auto Shop 101 but I can't remember (I took auto shop 50 years ago). The battery is on the charger right now - tomorrow I will delve into the beast. Tom, thank you for the info - I will check all that tomorrow. Today I changed the oil, checked all the levels trying to get her pretty. At least I have a pretty non running car. This has been a trying day.

[JerseyHarold]

If the car died when the battery was disconnected, it means the generator is not putting out any voltag and the car is running off the battery alone.  Check the generator, the voltage regulator, and wiring.

[Don Jordan]

Thank you - I'm going right now. Actually I'm going to pull then genny from one car and put it in the other. That will narrow things down. Thanks again.

[Don Jordan]

I know this thread is dead so I'm just sort of writing this to myself. Someone might see it. I guess this is just general information.

I took the generator out and took it to a shop for testing. The guy came back and told me it was putting out 10 amps. I have no idea if that is good or bad. He said it takes about 40 amps to run the car. Guess I found the problem. He's going to rebuild it. I'm ready for Tucson.

d-

[ptwothree]

I don't know.....I think in testing mode, these things either output at or close to max rated  or don't work at all.  What other work had been done to your genny prior to sending it to the shop?

[Don Jordan]

I hate to say it but it might be the original. (if that's possible) I've done so many things and sometimes I fail to remember. It's like it ran perfect then little things began happening. I found a small hole in the fuel line. I don't know if this could be true but I surmised that the electric fuel pump was just sucking air. I found the hole - replaced the line - tested the fuel pump and it made noise, it was running, but it was not pulling any gas. So I replaced it. Problem solved. But once it was started it just didn't run. I got it into the garage - while it was running I pulled the battery cable off. The car shut down. I looked at the voltage regulator but had no idea what I was looking at. So I figured first I'd have the genny tested. There aren't a lot of moving parts so when the guy tested it I figured it could just be brushes. I sure hope that's all it is.

[Don Coatney]

Electric fuel pump, remove the battery cable, car dies. Sounds silly but you might want to think about this a bit.

[Dave72dt]

I'm surprised all the gen would put out is 10 amps.  Does it have an adjustable 3rd brush?  Did it die immediately after pullling the bat cable off or did it linger on for a bit?  battery voltage?  Fuel flow at the carb?  Fuel level in the carb?  How do the points look?  Electric pumps are supposed to be pumps and don't work well at sucking so mounting it close to the tank is important.  Do you still retain the original mechanical  fuel pump and is the electrical a flow through type?

[_shel_ny]

My '51 had low gen output at idle. Car would die if the battery cable was removed. Wind it up good so there was more output (as indicated on the amp meter, and it would stay running when the cable was pulled.