Dies on the road

P

Plainsman30

Member
When driving the Model A at road speeds, the car will sometimes begin running very badly, becomes very load, and loses power. It backfires and bangs loudly, and also almost makes a clanking sound. It seems to puff through the exhaust pipe and carburetor. It will lose power to the point it won’t pull itself, even in the lower gears. Today, it happened 3 times on a 180 mile trip. The trick I learned today was to shut off the ignition and restart, and it then runs good again. The car has had this issue for some time. I have tried 2 distributors and 2 carbs with the same results. Both distributors and carbs were recently rebuilt. The car has about 60 lbs. compression on all 4 cylinders and has about 15,000 miles on an overhaul. Any hints on what to do would be appreciated.
 
Do you have one of those little fuse holders on your starter?

What year car?

Stock points and condenser?
 
Responses for Bob and Jim,

The car is a stock 1930 Model A.

I do have a fuse holder on the starter with a 30 amp circuit breaker in it.

I have tried 2 distributors. One has a stock points set up and the other has a "modern" points set up. I did have trouble with a wireless lower plate shorting out and went back to a wire on the modern set up. Today, I was using the "modern" set up which has new high quality points and condenser recently installed.

I have not tried a different ignition switch. The one I am using is about 8 years old and is not a pop out switch.

The coil is probably 5 years old.
 
Could be an intermittent obstruction at the fuel line. Could you have rusty chunks or something similar sloshing around in the gas tank?

I would also consider trying another coil.
 
It's the coil. I had this problem with my cub cadet tractor. Eliminated all other things, then changed the coil. No more worries. Change the coil.
 
Since you have to turn the car off and restart to make the car run correctly that eliminates fuel problems in my opinion as removing power has nothing to do with fuel.

I'm thinking ign switch as well. Vibration is causing the connections to become dirty and the act of turning the switch off then on wipes the connections.
 
I agree with Mr Nut. Fuel restriction is worth checking out. Also, you say you turn it off and then it runs good.? Possibly a loose or weak electrical connection, that holds for a while then the resistance builds up and you lose voltage.
 
Mike Kiser said:
Responses for Bob and Jim,

The car is a stock 1930 Model A.

I do have a fuse holder on the starter with a 30 amp circuit breaker in it.

I have tried 2 distributors. One has a stock points set up and the other has a "modern" points set up. I did have trouble with a wireless lower plate shorting out and went back to a wire on the modern set up. Today, I was using the "modern" set up which has new high quality points and condenser recently installed.

I have not tried a different ignition switch. The one I am using is about 8 years old and is not a pop out switch.

The coil is probably 5 years old.
Click to expand...

Try replacing the circuit breaker with a real fuse.

When it starts to die, swing the windshield out far enough for you to loosen the gas cap. Leave it sitting there loose. See if that helps.

These intermittent problems are a real pain to find and fix.
 
With a repro ignition switch, how much can you turn the key to the left before the engine stops? If you barely start to turn the key CCW and the engine quits, then I'd suspect a bad switch. I tood the rear cover off mine and made the contacts better, and haven't had any ignition problems since.
 
I will look at all suggested ideas tomorrow including the coil, fuse holder, fuel restriction and switch.

I notice nobody has mentioned anything major like a broken valve spring or something causing a valve to stick. That was what was concerning me.

What is interesting is the motor doesn't just die out and quit, it just runs terrible and produces very little power. The intermittent part is a problem also as it has sometimes gone several trips and not acted up at all.
 
The new fuse holders are WAY better then a few years ago;
Better
16100.jpg

Weak
A11450SF-7248.jpg
 
Mike Kiser said:
... The trick I learned today was to shut off the ignition and restart, and it then runs good again. ....
Click to expand...

This is a telling clue. I think it eliminates fuel related problems and things that wouldn't change quickly, like the coil. Although an intermittent contact anywhere in the primary electrical circuit is possible, I join the others betting on the ignition switch. I've had to replace about four of these over the years--they can make you crazy. Don't cheap out on this item.

If you want to experiment, you could rig a temporary toggle switch in its place, or maybe a couple of wires hanging out behind the dash that could be wrapped together when the problem occurs. If you let the switch in place, so the toggle or wires are in parallel with it, the moment the problems starts, flip the toggle. If the car straightens out, you've identified the source.

Steve
 
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How long do you have to wait before restarting ? If you don't wait and just restart, then loosen the fuel cap and drive it like that to see if that helps. The vents tend to plug up. When its acting up try wiggling the key switch and see if that helps.
 
Thanks to all who replied. I got started today trying the posted suggestions. It will be a week or more before I can again work on the car and test it. I will post an update later, hopefully with a success story.
 
Working on a 31 Vic. Been having an intermittent problem where is just almost dies then goes back to running. Tom suggested the fuel line where it goes into the carb maybe was in too far. I pulled it and trimmed the end back about 3/16 -1/4 inch. Took for test drive, seems ok now.
 
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