77 Super Beetle Convertible.

I was driving a few weeks ago and all of a sudden I seemed to run out of gas, which was odd because I knew that I definitely had at the very least a half tank of gas (spotty fuel gage). I lost power, sputtered, with the engine finally cutting out when I pulled over. It would not turn over until I had added 1 gallon of gas... then she fired right up and ran like a champ!

This has happened a few more times since. The car will run fine when full , but after I use approximately 1/8-1/4 of the tank it seems like the fuel supply is cut off. A few questions come to mind:

1. I know the fuel over flow hose, the filler neck hose, and the gas cap need to be replaced (have them on order)... could any of these be causing the problem? Will replacing them solve anything other than a strong fume odor when I fill up?

2. My father mentioned a preformed hose that goes from the bottom of the tank to the fuel filter. I know I have a regular fuel line running here and could not find the preformed hose on MAMW or elsewhere.... ideas?

3. If none of the above are feasible, or if there are any other possible causes I would really love to know! Thank you.

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MY72BUG
Hi Katiegreen.  Welcome to the world of VW.  Fuel supply problems can be real torture.  First, is your car a carbureted or fuel injected car?  I'm personally not up on fuel injection so I cannot comment on any problems which are special to fuelies.  Common problems are a buildup of crud in the bottom of the tank, fuel lines and fuel pump filtres.  A lot of VW's will also have add-on fuel filtres between the fuel pump and the carb.  Watch for fuel line kinks where the fuel line leaves the tank.  You should be able to disconnect the line from the fuel pump and freely blow air through to the tank.  The additional weight of another gallon of gas may be enough to free a kink and allow a flow of fuel.  A valid test would be to replicate the problem.  Let the car conk out but have a few tools with you.  When it stops, before you add more fuel disconnect the line from the fuel pump to the carb, lean it well away from the car and into a container which can catch the fuel.  Crank it over.  Do you see spurts of fuel coming from the line?  If no - then trace the line back to see where you are losing your supply.  If you do have fuel, you may have an ignition problem of an intermittent nature.  Allowing the car to cool off  ( while you add fuel ) may allow the problem to temporarily resolve itself.  Test for spark by sticking a screwdriver up a sparkplug boot and then bringing the screwdriver near ground on the engine while someone cranks the engine.  ( don't ground yourself at the same time! )  Do the whole process of elimination routine to trouble shoot the problem.  Draining and cleaning the tank should always be considered.  Tank removal is not too difficult.  There are shops which specialize in this sort of work.  Good luck with the project.  Let us know how it turns out.   Dan ( MY72BUG ) in Goderich, Ont.
I'd rather have a partial bottle in front of me than a partial frontal lobotomy.
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katiegreen wrote:
77 Super Beetle Convertible.

I was driving a few weeks ago and all of a sudden I seemed to run out of gas, which was odd because I knew that I definitely had at the very least a half tank of gas (spotty fuel gage).


Assuming it is a carb and not injected there are 5 main sources: tank, line, filter, pump and carb.

I am assuming it is not the carb since that should be indifferent to the amount of fuel in the tank.

Working back there should be a filter between the carb and the tank.  It should be clear plastic with an orange filter.  The wide "cap" should be towards the carb.  it should be clean.  If not change it, it only costs about a buck.  if it is clean it should be about 1/4 to 1/3 full when not running and 1/3 full or more when running. 

the pump:  you should see some gurgling in the filter when running.  if not the system might be running on gravity from a full tank.  you can pull of the filter and start it.  it should pump gas up the line and into a cup.  be careful doing this because it will likely start with the gas in the carb unless you disconnect the coil.

The line.  I like the ideal of disconnecting the line at the pump input and blowing.  It should bubble back to the tank.  I've never tried it.  It may required compressed air.  Gas should flow from the tank to the pump inlet freely.  collect a quart or two and see if there is any crud.

The tank:  I had a Chevy with a plugged vent hole in the cap and it would cause a vacuum in the tank and would stall.  try running it with cap off or on loose. 

Let us know what you finally figure out was the problem



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