Electrical tale of woe

[hoof]

I recently rolled into my garage with my ignition cable smoking. I replaced the wire, along with my coil. I found that the ammeter wire was melted also. I disconnected the ammeter, and the car runs great.
But...
My horn, lights and turn signals only work if the car is running? The starter seems to work fine. I am not 100% sure about the turn signals, but I know the lights and horn would work before with the car off.
Other than the ammeter I have changed nothing. I thought maybe the battery was about dead and the accessories would only work with the alternator turning, but it starts, and when I was testing the ignition system I have over 6 volts with it shut off.
Any ideas?
Thanks,
CHAZ

[Bob C]

With the ammeter disconnected the battery is out of the lighting and charging
system. If you have a stock charging system the generator will be going up in smoke also.

Bob

[RHOLDE]

Hi I had a problem like yours and I found that my metal conduit that comes from the alternator to the junction box was shorting out at the terminal in side the box

[hoof]

I will run new wire and see if the ammeter is actually bad, or if the wire itself is shorted out. I was just being lazy not replacing it in the first place because it is in a loom with another wire that I will have to disconnect and pull to replace those that are bad.

Any way to test the ammeter and see if it is the problem?

I will also check the conduit from the alternator, although I do have it taped around the end and secured.

Thanks,
CHAZ

[larrys40]

hoof,

Make sure you don't have one of those poor afterarket aluminum ammeters. They are of course silver in color. Just like aluminum wiring in a house they are bad news. Make sure all your connections are tight and the insulators on the back of the ammeter are good shape. An original ammeter is best if you have one. I would suggest also replacing the dash harness with the 3 wires in it to the terminal box. Make sure the terminal box studs are tight. IF they wiggle at all it is probably an aftermarket box and the studs have been hot and will short if they haven't already to the firewall. We know it doesn't have a fuse in the system between the starter connection and the terminal box so it would be a good idea to add one of the 30 amp inline fuse holders.

I know everyone's scared of the "electrical system" and you should be if the wires and connections are in poor shape.. so replace them, use the info in the Les Andrews books and replace them. give us an update!
Larry Shepard

[eagle]

Sponsored Links (Register now to hide all advertisements)

Sounds like an advertisement for a fuse or circuit breaker. Use a continuity tester or test light to IDENTIFY the problem before you start "FIXING".

[larrys40]

Originally Posted by eagle

Sounds like an advertisement for a fuse or circuit breaker. Use a continuity tester or test light to IDENTIFY the problem before you start "FIXING".

Not an advertisement at all... just common sense and a good move. I spent 22 years of my 1st career as an electronic tech, and don't use test lights, I use good quality fluke meters to find electrical issues as needed, along with my experience. Otherwise, the wire becomes the fuse.

It sounds like if he had a wire burn in a harness that it probably damaged the other insulated wires as well. Dash Harnesses are less than $15, certainly money well spent. He may and probably does have multiple issues.
You just have to find and fix/replace harnesses to make restore integrity to the system.

Hoof, post a few photos of what you have and maybe that will help understand what you have going on. ( terminal box, generator connection, wires at ammeter/dash, etc)
Larry Shepard

[H. L. Chauvin]

Hi Chaz,

I remember reading my Uncle's very simple and imaginative 1935 house wiring book as a teenager where it compared (+) and (-) electrical current flowing through electrical wires to plain water flowing through metal water pipes.

Electrical connections along the way were compared to metal pipe Tees and Caps, and bruised insulation on wires and loose electrical connections were compared to metal water pipe leaks.

All one had to do was to prepare a diagram beginning at a source, (like at one's electrical meter, or car battery), and return to this one source.

If you get a Model A electrical wiring diagram with proper color code for different wires, you will be amazed how Model A wiring could be mastered by kids at the second grade level.

But as we get older, most brains become so clogged with electropositive and electronegative thoughts that we need a PhD Electrical engineer to wire a Model A tail light.

Maybe just try reading a Model A wiring diagram ..... smoking Model A wires close to a Model A gravity flow fuel tank system is a concern.

[hoof]

So a model A is a "closed smoke" system, you know there is a problem when it "lets the smoke out?"

There is a 30 amp fuse inline where I believe it should be (physically down near the starter). It did not blow when the ignition wire fried. When I replaced the ignition wire it blew immediately until I disconnected the ammeter.

I had to use a voltmeter to figure out why I wasn't getting 6 volts at the points (multiple problems). The new top plate wasn't contacting the old bottom plate in the distributor. Got that straightened out.

I will replace the wires to the ammeter, and I have found a few tricks online to check and see if the ammeter is good, I will do that before hooking it back up.

Thanks for all the help.
CHAZ

[Bob C]

What ignition wire fried?

Bob

[Mitch//pa]

""Top plate was not contacting th old bottom plate""

Please expand on this

[hoof]

Originally Posted by Mitch//pa

""Top plate was not contacting th old bottom plate""

Please expand on this

New upper distributor plate was not contacting the distributor below. The contact from the points was bent up where it did not contact the bottom of the distributor and there was no juice to the points.
CHAZ

[H. L. Chauvin]

Hi Chaz,

With your enthusiasm, your voltmeter, and desire to learn former Forum methods, it would not be surprising if next week you reply with an article:

How to wire a Model A.

[Tom Wesenberg]

Originally Posted by hoof

New upper distributor plate was not contacting the distributor below. The contact from the points was bent up where it did not contact the bottom of the distributor and there was no juice to the points.
CHAZ

So, it sounds like you are using the wireless lower plate, where a springy contact strip connects the two plates. These are known to cause problems, and a lot of people have gone back to the nice 100 plus strand flexible wire.

[hoof]

Originally Posted by Tom Wesenberg

So, it sounds like you are using the wireless lower plate, where a springy contact strip connects the two plates. These are known to cause problems, and a lot of people have gone back to the nice 100 plus strand flexible wire.

Yup, that is what I got. This is the first model A I have ever dealt with, so I didn't realize what I had wasn't "normal." I had to bring up the bottom plate, and "recontour" the top plate contact to get voltage to the points.
CHAZ


"What ignition wire fried?"
The wire that burned was the shielded ignition wire from the key to the side of the distributor. I don't know if the ammeter wires were a problem or collateral damage.

[Mitch//pa]

Thanks Tom for clearing that up... And yes I have also seen nothing but int driveability to all out break downs with the wireless lower plate...

It's best to use the original set up with a wire so you get a positive connection to the points

[Tom Wesenberg]

I am surprised the switch to points wire would be fried, since that is on the ground side of the coil. I wonder if someone accidentally touched power to the switch or wired it wrong.

When I was in high school I accidentally touched the power wire to the points side of the coil, and it heated up the points and took the temper out of the spring. This of course then became my governor and limited my speed to about 30 MPH until I figured it out.

[Mitch//pa]

Maybe you can post some under hood pics, sometimes we can spot certain things

[hoof]

Before I burned the wire off the car ran, although poorly. I couldn't put a load on the motor. After the wire burned I put on a new condenser and points, and a new coil, and of course replaced the ignition wire and it runs fine now, albeit with the ammeter disconnected.
I have a wiring diagram to check, and I will post some pics.

CHAZ

[hoof]

Update:
I'm an idiot.
I pulled the wires out of the dash today and made up a new set. I cut the ammeter wires each about 2" short. I have just enough materials left over from an old rewire in a '53 Plymouth to do another set. Maybe a little longer this time.

I still would like to test the ammeter before wiring it back up and I am not sure how?

CHAZ