Electrical: Car shuts off after I drive it a mile or so

[studeguy54]

Here's one that has me puzzled....my '41 President 4-dr (all original, barn-fresh) shuts off after I drive it as mile or so, and has done it the few times I've driven it this Spring.

Gas tank has been hot-tanked, coated and all new lines to the engine made. Fuel pump has been rebuilt by the best in the business, Arthur Gould, and works fine. Fuel bowl fills, and gas is flowing to the carburetor, and the car runs fine in the garage. an inline see-through filter is showing NO dirt accumulation, as I would expect, so I don't think it is a fuel delivery problem.

If I take the car out and drive it less than a mile, the car will shut off like someone turned the switch off. In one instance, if I wait a bit, the car will start up and run and I can drive it home. The last time, we towed it home. I'm thinking it has to be coil or condensor-related. The car has the original through-the cowl coil on it, but it was bypassed some time ago, and an aftermarket coil is mounted on it. I'm at a loss to figure out what is happening.

Are all coils (6V), the same? In other words, would any 6V coil work on the engine, or does it have to be specific to the brand of car?

Anyone know what is going on?

Studeguy54

[whacker]

Did you use a new gas cap? The original gas tank cap is vented, the new ones are not. It can pump gas until a vacuum is built up in the tank, then it starves for fuel. Try putting the old gas cap on, see if the problem goes away.

If it does turn out to be the coil, get a 6 volt coil that fits in the mount.

[BobPalma]

Condenser sounds suspect. As cheap as they are, I'd replace it first.

That assumes you checked the fuel supply in the carb immediately when it "shuts off" and have verified that there is gasoline in the carburetor, and an adequate amount at that, when the car shuts off. BP

[jimmijim8]

Still do not rule out the coil and I would replace it just to be on the insured side. If you find it not to be the problem, carry it in the trunk as a back up for you or a friend. jimmijim

[christophe]

Sounds also like a condenser to me. Usually, a bad one gives the symptoms of a gas lack. Check also the temp of the coil. If it's hot you may have a problem with the wire between the coil and the distributor and/or the isolated plug on the distributor (wire touching ground or isolation defective on the plug).
Best of luck.

[Mike Sal]

I vote condensor.
Mike Sal

[studeguy54]

Guys,

Thanks for your help, but I still have the same problem. We have replaced the old coil with a new 6V coil, and have replaced the condensor with a new one. I drove the car on Saturday for about 20 minutes in and out the lane I live on, and put the car under a load on several nearby inclines. No problem.....but, when I ran the car to the end of the lane on the last trial, and attempted to turn around to run back to my garage, the car shut off and would not start. We have spark, but no fuel delivery to the carburetor, and when we pump the throttle, no gas is apparent.

We left the car set for about an hour, then attempted to start and run the car. It started, and ran about 1/4 mile before it again shut off again. Waited another hour, it started again, and I was only able to run it a short distance again, before it shut off..no fuel delivery.

Any thoughts??

studeguy54

[raoul5788]

I'm guessing you need to rebuild the carb. It could have a bad accelerator pump or bad float.

[Tom Bredehoft]

Before you rebuild the carb, try running without a gas cap. If you have a modern gas cap on your tank it will not let air in to replace the gas pumped out and your pump won't suck against a vacuum.

[garyash]

I had similar problems on my '65 Wagonaire when I first got it. I eventually traced it to a bad ground connection from the points plate to the distributor housing. If all else fails, take the distributor apart and clean up the contact areas where the small, braided ground wire attaches under the plate.

[55s]

I agree with Tom. No vent in gas system.

Other:
Weak fuel pump. If old neoprene gasket, it may not like ethanol.
Incorrect fuel pump. Arms are different on some aftermarket ones.
Small hole in gas line
vapor lock - does the fuel line run close to the engine?
small bit of dirt in the gas line at needle valve.
water in gas

[jclary]

Guys,

Thanks for your help, but I still have the same problem. We have replaced the old coil with a new 6V coil, and have replaced the condensor with a new one. I drove the car on Saturday for about 20 minutes in and out the lane I live on, and put the car under a load on several nearby inclines. No problem.....but, when I ran the car to the end of the lane on the last trial, and attempted to turn around to run back to my garage, the car shut off and would not start. We have spark, but no fuel delivery to the carburetor, and when we pump the throttle, no gas is apparent.

We left the car set for about an hour, then attempted to start and run the car. It started, and ran about 1/4 mile before it again shut off again. Waited another hour, it started again, and I was only able to run it a short distance again, before it shut off..no fuel delivery.

Any thoughts??

studeguy54

Looks to me like you have one of two problems. 1) AS someone has already suggested...you may have a non-vented gas cap. If that is the problem, your car will run until the pump finally pulls enough of a vacuum to prevent the fuel pump from being able to pump. A quick test for this would be drive it without the gas cap. If it don't shut off, put on a proper vented gas cap.

2) You could have gas-logged (as in "water-logged") debris. That is debris that will sink to the bottom of the tank and stay there until it is disturbed and "fluidized" by the movement of the vehicle. If your pick-up tube inside the gas tank has a screen wire pre-filter, the debris will accumulate around it and shut off your flow of gas. After the car sits for a while...the stuff will float back to the bottom of the tank and allow you to start the engine. Once you begin to drive again, the cycle will repeat and shut off the car again. Some of these carburetors have a little filter screen in the inlet fitting where the fuel line connects. This can also clog and cause the fuel to stop.

Check these things out and let us know what you find.

[studeguy54]

Ok....got an email from the guy who rebuilt the pump, and here's what he said:

"Sounds like while the vehicle was sitting one of the valves may have become partially stuck. when the valve doesn't seat properly it does not allow the pump to build as much pressure as needed and the very low pressure can often cause vapor lock as the motor calls for more fuel or heats up to full temp. This is fairly common when vehicle sits for extensive amounts of time due to the ethanol in today's fuels. The ethanol forms a gel that does not let the valves seat properly".

At his recommendation, I've sent the pump back to have it looked at...I'll let everyone know the outcome.

Thanks, everyone, for your input.

studeguy54

[starlightchamp]

Same thing happened to me on my 57 SilverHawk. Start, run a mile or less and die. Wait a few minutes,
start and run a short distance again. Replaced carb, checked fuel pump, finally blew down fuel line to tank.
Was barely able to get air through----kinked rubber hose !!!

[studeguy54]

I believe one of the reasons for this accumulation of "gel" relates to the rubber being used for the line also. If you are using an older-style rubber fuel line, it might be smart to change your lines to the newer rubber available. The newer line, I am told, is more friendly to the corn-ethanol fuel we have to use in our vehicles these days.