Grand Wagoneer fuel supply problem?

Yes, carburetor still in place.

Pouring gas in it lets the car start and run again (until it does it again).

Its like the carburetor empties but doesn't refill.

Either a fuel filter going bad or a plugged up air filter on the gas tank vent would be my guesses.

When was the last time you changed the air filter on the gas tank vent? When plugged it makes the vehicle act like it runs out of gas. Prime it or let it sit for a while and the vacuum goes away and you are good to go for a bit.

Mike

Could it be the float bowl in the carb? Mine drains out so it takes a few tries to start it each morning. Maybe yours is worse?

Fred

You are now describing an upside down gas filter or a pinhole leak in the suction side of the gas line.

The filter has 2 outlets. The center outlet goes to the carb and the top outlet goes to the return line. If the return line outlet isn't above the carb one, gas will syphon back to the tank air locking the carb or acting like a vapor lock, which is what the return line is there to prevent.

If the gas line has a pinhole leak on the suction side, air can get in and the gas will also all drain back to the tank. Usually these leaks just leave a slight stain on the line until they get really bad. I usually see them where the rubber hoses hook to the steel line at the front or rear of the frame.

Mike

Stuck carb float, clogged fuel filter, bad fuel pump, or pinhole leak between the pump and the tank.

F. J. Townsend, III proclaimed:

Thanks Bill

I'll have to get one of those and see if that fixes it.

Fred

All you have to do is take off the gas line where it comes into the pump after you had it running. If gas pours out, the valve is bad.

Mike

Thanks, Mike (and others):

Can't find a fuel tank vent in the manual. There is a vapor canister filter but I'm not sure that would cause the problem.

I changed out the fuel filter and all went well until the other day when I started up and let the GW idle with the defroster on for 30 minutes after a big snowstorm).

The engine died during this period and was extremely difficult to restart, even with priming, etc. Now after a restart it runs and starts normally again.

I noticed from the shop manual that there is an in-tank filter and I still wonder if there could be a tank problem causing this. I have had a long-standing problem with an inaccurate fuel gauge (not corrected with replacement) and perhaps the two problems are connected.

It is such an intermittent symptom it seems very difficult to troubleshoot.

Thanks,

Frank Townsend

The charcoal canister or emissions or vapor canister or whatever name they want to call it is the gas tank vent. If plugged, it 'will' put a vacuum on the gas tank and carb float bowl that imitates running out of gas really well.

The air filter on the canister is supposed to be changed every major tune up or in my case, every time I finish 'playing' in the mud pits. I have had to drive home with a loose gas cap a few times...

The test for it is to crack open the gas cap when it stalls out. If you get a whoosh of air and the engine starts back up, you have found your trouble.

The in-tank filter is just a sock shaped screen. They 'can' plug up, but man you have to have an amazing amount of crud in the tank to do that. Blowing back through the gas line can clear a plugged screen or blow it off the line. If it is that dirty in there, the tank would need flushing.... You also would get plugged up gas filters very often.

Mike

"F. J. Townsend, III" wrote:

I replaced my sender unit a few years ago. Now the sender seems to be having problems again. Or maybe just a bad connection because of the infamous GW gas tank area rust! Fred

Here's an update:

I finally got a replacement vapor canister filter only to discover when I removed the old one that (1) most of the old filter was missing and (2) because of the way the canister is assembled (the plastic base is glued on), the filter is not really replaceable.

even though the filters are supplied as an extra part, trying to work the new filter into the place where the old one was basically destroys the new filter. Besides, since the old filter was so deteriorated, I assume that the canister is probably no good anyway.

I ordered a new one from moparpartz.com, and will see if that seems to be a solution.