Weird fuel issue keeping me from driving my coupe. Any ideas?

[carbed87]

So i have a 30 coupe, stock banger (other than a snyder head) and i seem to be having a fuel issue.

I can go out, start my car right now, let it warm up, and even drive it around a little, but then it will just up and die.

So here is what it does: after it dies, I can pull off the fuel line from the carb, open my fuel valve, and it will pour out no problem.

When i hook it back up to the carb, it will not deliver fuel. I know this because if the sediment bowl is empty, it will not fill up until i loosen the fuel line from the carb again.

I initially thought this may bt a fuel cap issue...does the same thing without the cap on.

It has left me stranded 3 times. All three times i have pulled the carb off and completely taken it apart, but there is never any debris in it.

i also thought this MAY be a spark issue, however a new coil, ballast resistor, condenser, and points have not made a difference when it does not want to run.

Any help would be great! it's a shame to have this car in my garage and be too scared to drive it.

[Jim/GA]

This is frustrating and you are not alone. A few things to check:

Remove the plug with the brass screen inside the carb and look for debris in there. Clean the screen.

Make sure the end of the fuel line is not going in so far as to touch the brass screen that you just removed and cleaned. This is important.

Are you using a polymer tipped needle valve in the carb? Do you know how old it is? If in doubt, replace it. They stick shut sometimes when the rubber presses against the seat for a long time. They are good valves, they just don't last forever.

These are the simple things. Beyond this it gets more complicated to diagnose through text message and a phone call is in order.

Good luck with it. Let us know what you find.

[Terry, NJ]

I too, have a 30 coupe with the same issue. And I'm scared to drive it very far. I've stripped out all of the fuel system except the tank. It has a "B" carburetor and now the stand up filter plus the extra filter in the sediment bowl, and some very crossed fingers. My problem seemed to be a clogged jet and whatever was clogging it was so fine that it wasn't obvious. The carb. had to be blown out with air and it would run well for a while. Short runs of a mile or two. Much longer, and it was sure to "strike". After much cleaning, I think I have it.
Terry

[Keith True]

Take the drain plug out of the carb,and let the fuel run out there.Watch it run out for 3-4 minuted.The flow should hold steady.A minute is not enough.Give it some time.The sediment bowl not filling with the line hooked up is normal.If the carb is full,and the float valve is closed,the air in the bowl and line will hold the fuel back.As soon as the carb calls for fuel you will see fuel start to dribble into the bowl.You can burp it at the line like you have been doing,or loosen the glass bowl and bleed it there.You really need to isolate fuel/electrical before throwing any more parts at it.I just spotted something else in your post,ballast resistor?? In a stock A?

[Pilotdave]

You said stock so I'm assuming a Zenith carb. Three possibilities come to mind:

1. Float valve sticking closed
2. Plugged fuel strainer
3. Fuel line inserted too far into the carb caused by too much line extending beyond the "wedding band" - should only be about 1/8"

Others may have other ideas! Good luck - please let us know how you make out.

Dave

[William Kelchner]

Sponsored Links (Register now to hide all advertisements)

Good morning. Did this problem suddenly appear? I went through this frustrating problem myself. Good fuel flow, spark, etc. Car would run for several minutes then just shut off like clock work. I eventually replaced the Zenith carb with a rebuilt one and replaced the dist with one known to work and haven't experienced the problem since. Early in my battle with the car I found the end of the fuel line that goes into the carb was longer than the recommended 1/8 inch. At any rate a number of the members reminded me that most carb problems are electrical

Bill K

[Pinesdune]

What you're describing sounds like an air lock, do you have a "high spot" in any of your fuel lines that could possibly trap air and cause a restriction, or possibly your float is set a tad high restricting flow/starving the engine. Just throwing a couple ideas out there, hope you find what's going on


Saving iron from the scrap pile one piece at a time

[holdover]

"3. Fuel line inserted too far into the carb caused by too much line extending beyond the "wedding band" - should only be about 1/8"

Replaced the line that came on the car with a correct one and coupe died as I was driving down the road a short distance from my house, loosened the line on the carb and pulled it back a bit and there was plenty of flow, but noticed that it was pushed in too far, I thought it was bottoming out, pulled it back a bit , tightened it up and been driving ever since.. Hope your fix is as easy.. Good to carry tools with you!

[George Miller]

Did you check for spark. The fuel bowl would stay empty if the carb does not need gas. I think you have a ignition problem, like a condenser. Check for spark when it stops. Should be a nice fat blue spark, not a yellow one.

[3.6rs]

You are not alone ; I had this once (only once). I took apart the carb but there was nothing wrong with it.
After I reinstalled the carb everything was ok again. Don't know the cause !

[w.michael]

As Jim TX said above, the float valve may be sticking in the closed position. This may happen even with a new valve, not just with an aging valve. Try tapping lightly on the carburetor near the valve and see if that frees the valve. You can often get it to "break loose" without disassembling anything.

W. Michael

[carbed87]

Wow! thank you all for the prompt responses! A couple things:
1. the fuel line being inserted too far into the carb could most definitely be a factor. Will check when i'm in the garage tomorrow.

2. I have done a carb rebuild kit from Bert's, but I've heard the valve could still possibly be an issue. Doesn't someone sell an updated valve somewhere?

3. I have a ballast resistor because i am running 12v electrical with a normal 12v coil, but a stock (but newly rebuild by Bert's) distributor. Should i bypass it?

4. I am certainly not ruling out the fact that it could be electric, however the first time this happened it quit on me when i got it to central city for the hill climb. Messed with it all afternoon throwing a coil, condenser, re-setting points...etc no dice. Finally fired up after i completely disassembled the carb and put it back together. But like i said, i am not ruling out anything.

Thank you all for the help!

[Hook]

I agree with George in post #9. Make sure it's not electrical by simply checking the spark next time it quits. I had a problem like yours, towing the A home twice. I kept changing parts in the distributor including putting in a complete new one with all new parts. Finally found a thread here on how to check the ignition system and found my switch was faulty and I had a problem with the shielded wire running from the switch. The main problem was with the switch that was causing a drop in voltage. If you find it's electrical, there are many threads on how to isolate the problem without throwing parts at it like I did!

[George Miller]

I have said this many times. If it starts running bad pull out the choke slowly and see if it helps, if it does you have a gas problem, if not you have a ignition problem.

[captndan]

Originally Posted by George Miller

I have said this many times. If it starts running bad pull out the choke slowly and see if it helps, if it does you have a gas problem, if not you have a ignition problem.

If you have any rubber hose in the system replace it and use gas rated hose or better all steel. I have seen rubber hose separate inside where you can't see it.
Try George's test first.

[steve s]

In every one of the cases I have seen of this behavior the problem is an aftermarket fuel filter. The "micro" filter held in the sediment bowl with a little spring seems to be the worst, followed by one that has been inserted in the middle of the gas line between bowl and carb. For some unknown reason, they seem to work ok for some people but not for others. My theory is that they work for people whose system is so clean that they don't really need them. Remove any extra fuel filters is the first thing to try for fuel starvation, which sure sounds like your problem.

Here's a picture of all the fiilters I've tried. The red fiberglass worked the best but it's been replaced by a paper model that does not work for me.

[Pilotdave]

With a 12v system, the coil should have an internal resistance of 3.8-3.2 ohms for a 4 cylinder engine. Most sold have two little internal resistance as they are designed for 6 or 8 cylinder engines. The ballast resister you're using MAY be in there to raise the resistance to the right level, but you'd be better off dumping it and making sure that you have the proper resistance coil.

If the quick fix suggestions above don't fix it, why don't you grab a photo of the fuel line from sed bowl to carb and post it on here?

[mantta]

Check that filter in the inlet of the fuel cut off valve. You have to drain the tank and remoe the valve to check it. I had that problem and, that was the culprit. Then again, some cars may not have that filter. It is actually a fine mesh screen.

[carbed87]

Originally Posted by mantta

Check that filter in the inlet of the fuel cut off valve. You have to drain the tank and remoe the valve to check it. I had that problem and, that was the culprit. Then again, some cars may not have that filter. It is actually a fine mesh screen.

not sure if i have that, but would that really be an issue if the fuel flows freely regardless of how the engine is running?

[carbed87]

Originally Posted by Pilotdave

With a 12v system, the coil should have an internal resistance of 3.8-3.2 ohms for a 4 cylinder engine. Most sold have two little internal resistance as they are designed for 6 or 8 cylinder engines. The ballast resister you're using MAY be in there to raise the resistance to the right level, but you'd be better off dumping it and making sure that you have the proper resistance coil.

If the quick fix suggestions above don't fix it, why don't you grab a photo of the fuel line from sed bowl to carb and post it on here?

I like your idea. Would you have a recommendation as to what coil? Additionally, do you think that this may be something that would cause the vehicle to not run?