Odd Electrical Problem...

1955cj5

1955cj5

Well-known member
Had the Model A parked around side of the house. When I went to move it into the garage about halfway there it coughed, sputtered and quit....wouldn't start..had to push it into the driveway..

Sounds like a fuel issue....

Fuel valve is on, fuel in tank, vented cap but removed it anyway..plenty of flow at the carb...

Float must be stuck..

Take carb off, remove cover, bowl full of fuel, float is fine..I blow out the passages as long as I'm there..

Replace carb..

Still won't start...

Thinking electrical now..

There is power at the points but it varies from 6 to 4 to 1.5 volts..hmmm...

Changed the condenser..no change

Checked timing..it was fine. I had to pull the distributor to remove the condenser because the brass tip of the condenser turned with the screw...also checked the wire under the lower plate...all OK

Power at the starter, fuse block, and passenger side of the junction box, but only about 1.5 volts at the other junction box stud...

Wiggle things a bit and check again...6v everywhere...tried the lights and horn but they won't work....weird..

Checked the voltage again and it's back down to 1.5 on the drivers side j-box post...

Ammeter?

Pulled the instrument panel and checked continuity on everything with a voltmeter, including the ignition switch and all checks fine...

Except...

There is little or no power on the output side of the ammeter, the side that goes to the drivers post on the j-box..

Tighten the nut...then everything was fine...it started and smoked because it was flooded by now but ran great after it cleared.....

This afternoon, repeat performance...won't even start this time..

But I knew where to look..

Took out the ammeter, and one stud was loose in the case...I didn't notice it before...

I tightened it up, re-installed the wires etc, and went for a 10 mile drive!
 
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Wow, nice work. i had some electrical issues with my 49 F3 and it kept me out in the shop till 11 pm four nights in a row as well as numerous questions posted on ford barn. Your post has enough information in it that I may just print it and keep it with my shop manual.
Thanks,
Trout
 
Question in my mind.... one of the VERY first checks I do is key on, pull off the coil wire, reach across the engine and pull the starter rod. Check for spark to metal. Did you check for spark or go through all of the carb and other work first? Not trying to be a smart***, just curious as it is about the first thing I would think to check.
 
The very first thing that I do when my A turns over but will not start is hit the horn button. I saw that advice in a video. It makes a lot of sense and can help steer you in the right direction.
 
As eagle said, do the easy checks first to narrow it to fuel or spark.
The ammeter and terminal box are two fairly common trouble spots because they aren't in the open and are often overlooked.

When the fiber washer is missing from under the condenser screw head, then the brass terminal can spin before the screw is tight to the bus bar on the lower plate. Once it turns, the condenser should be considered junk, because if it still has the capacity to work, it is a real stroke of luck, but I'd consider it unreliable. Be safe and replace it with a heat proof one from the parts houses.
 
eagle said:
Question in my mind.... one of the VERY first checks I do is key on, pull off the coil wire, reach across the engine and pull the starter rod. Check for spark to metal. Did you check for spark or go through all of the carb and other work first? Not trying to be a smart***, just curious as it is about the first thing I would think to check.
Click to expand...

I had it set that it was a fuel issue, just because of the way it sputtered, coughed and died..kinda like i had left the fuel valve off....

Goes to show how initial mis-conceptions can send you in the wrong direction.

By the time I had gotten the volt meter out, and because the horn and lights didn't work, I finally got to the points and found intermittent voltage there...

I did go through some maybe unneeded steps, but only now do I know they were not necessary...

To directly answer the question...Yes, it occurred to me to check the spark from the coil wire, but only in passing as I was already checking the points and finding suspicious voltage readings...so I didn't...
 
Tom Wesenberg said:
As eagle said, do the easy checks first to narrow it to fuel or spark.
The ammeter and terminal box are two fairly common trouble spots because they aren't in the open and are often overlooked.

When the fiber washer is missing from under the condenser screw head, then the brass terminal can spin before the screw is tight to the bus bar on the lower plate. Once it turns, the condenser should be considered junk, because if it still has the capacity to work, it is a real stroke of luck, but I'd consider it unreliable. Be safe and replace it with a heat proof one from the parts houses.
Click to expand...

Well that was exactly the problem with the condenser....no washer, screw bottomed out and the brass tip on the condenser turned..

I had to drill out the screw, and there is no question that that particular condenser is "junk" as I cut the opposite end off hoping to get at it and hold it while removing the screw....

I had replacements....
 
1955cj5 said:
I had it set that it was a fuel issue, just because of the way it sputtered, coughed and died..kinda like i had left the fuel valve off....

Goes to show how initial mis-conceptions can send you in the wrong direction.

By the time I had gotten the volt meter out, and because the horn and lights didn't work, I finally got to the points and found intermittent voltage there...

I did go through some maybe unneeded steps, but only now do I know they were not necessary...

To directly answer the question...Yes, it occurred to me to check the spark from the coil wire, but only in passing as I was already checking the points and finding suspicious voltage readings...so I didn't...
Click to expand...
Aha! I understand. This spring when I got the A running, it didn't start when I cranked it. First thing I did is choked it a bit extra, then looked to see if there was fuel in the carb throat, there was. Second thing I did was check for spark, none. Cleaned and reset the points, lots of spark and started like a champ.
 
I suspect a possible candidate for my electrical problems was moisture in my ammeter --was getting hot... I blew it out with air... It no longer gets hot... Yet to say for sure this was my issue but so far so good... I have been driving my car at least every other day which too helps dry things out...
 
Goldhardt said:
At least you found it and got it fixed! Thanks for sharing!
Click to expand...

Yes, and I'm sure I found the problem, instead of just moving wires and tightening connections and then having it magically start working again...

It's always good to have a definitive cause and a reasonably sure repair!
 
mshmodela said:
I suspect a possible candidate for my electrical problems was moisture in my ammeter
Click to expand...
???

I would suspect a loose connection caused the problem. The connections were tightened when the ammeter was replaced.

Frank
 
Robi321 said:
If you suspect a bad ammeter would jumping the terminals work? essentially bypassing the ammeter.
Click to expand...

I was in the process of doing just that, attaching both the ammeter wires to one terminal...but then I noticed how loose the one stud was...

I see no reason why it would not work. There are no electronics in a simple ammeter just a strip or loop of what looks like brass and a needle on a pivot that senses the direction and intensity of power flow..

But we may learn more....
 
Robi321 said:
If you suspect a bad ammeter would jumping the terminals work? essentially bypassing the ammeter.
Click to expand...

An ammeter is really just a large shunt of brass that carries most of the current. along with the shunt, there is a small coil of wire that 'samples' the amount of current in the shunt and moves the needle an appropriate amount. this is a simple explanation, but bypassing the terminals with a piece of wire just adds another shunt in parallel.

Frank
 
The Model A ammeter doesn't use a small coil of wire like many meters use. The needle simply deflects due to the magnetic field set by the current passing through the brass strip. There is also a small wire magnet inside the case.

Be sure the ammeter nuts are clean and tight, and it should be fine.
 
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