Help! I've been chasing this rabbit for weeks. If I let the tank get below 1/4 (about), fuel stops flowing from the tank.

Here's what I've done. Replaced tank from my donor, new fuel pump, changed all soft lines, blown out hard lines, carb is new, filter is new (and facing right direction), checked and rechecked tank gasket and tightness at all line connections. Tried with gas cap on, and off. Confirmed that gas was in the tank and the gauge wasn't just off.

I got mad the other night and just poured the whole 5 gal. in the tank, with what was already in there it brought it up to 1/2. Sitting there thinking before I gave up and went to bed, I hit the starter. VAROOM! Now I was really PO'd. It's on jackstands in my shop waiting for wheels I'm having made for it, so I go and hit the starter evey few days. cranks and idles fine.

But he**, I'm afraid now if I get out on the road and it gets down to low, it'll quit. First time out I'm gonna take a 5gal can with me, but that don't fix the problem. I hate a semi fixed problem and not knowing what the real fix is.

Any ideas?

Thanks ahead of time.

Mike

 

Are you sure the fuel tank sending unit is working correctly? When you had the sending unit out, did you happen to shake the float?

The float is the usual culprit. It's made from two pieces of copper soldered together, solder breaks down, gas seeps in, float slowly sinks towards the bottom of the tank. It only takes an ounce or two of gas to throw off the dash gauge. The float and gasket are still available from Ford and NAPA. The complete sending unit is also still available from Ford.

1-C0AZ-9202-B .. Float

1-C1TF-9276-A .. Sending Unit Gasket

1-D7TZ-9275-G .. Sending Unit Assy. (includes float & gasket)

 

You can remove the float and check the resistance with an ohm meter... I don't recall off the top of my head (or anywhere else in my head) what the reading should be, but someone should come along and have the numbers.... Or you can probably find it in a Chilton's Manual....

 

The gauge shouldn't have anything to do with the fuel flow.

I am scratching my head because if some gas comes out all of it should, sending unit isn't part of delivery.


John

 

OP said when dash gauge reads just less than a 1/4 tank, no gas flows.

My question: Is the gauge accurate?

The way the sending unit floats were made, over time...allows gas to get inside them.

 

OK, I sees what you are saying, The reason no fuel is flowing is because the tank is empty.

The big question is there 1/4th tank of gas or a lying gauge??



John

 

I vote for a lying gauge.

When the gas stops flowing...remove the sender from the tank...look into the tank...using a flashlight, do NOT use matches!

 

Ok, I get where ya'll are comming from.

This is what happened in one instance. Truck is sitting idling, starts to die, then does. Won't crank. Removed air cleaner, no spray outa acc. pump. Remove lines (one at a time) all the way to where it enters fuel pump, no gas. Since it just ran out, pour in a couple of gallons, still won't pick it up. Blow compressed air into tank to get it to start to flow, then it stops. Acts like it won't syphon without the added weight of a 1/2 tank of fuel in it. I'm assuming it syphons because the gas exits the top of the tank. Thats why I tried with and without the gas cap on.

The float is new, but I did check it for leaks too. I confermed gas was in tank visually and by rocking truck to get an idea of how much.

 

You might want to check the fuel flow, with a clear plastic tube, for air bubbles.

The "pick up tube" in my tank had developed several small holes in it, which allows air to enter the fuel stream after they were exposed as the tank emptied...causing all sorts of stalling and intermittant run issues....once we replaced the tube, it worked perfect.

 

Ok, just to clear my thoughts, did you remove the little rubber line under cab where fuel tank mates with line on frame? You said "all" lines, but did you miss this one by chance? It might be collapsing and stopping fuel.

To check fuel gauge level, install unit in tank, get reading on gauge. Remove sending unit, measure level with wood stick and compare to tank height. Say, if it's 1/4 the height, then gauge should read 1/4 tank. Or whatever it measures out to. Not that this has anything to do with stalling, but it will comfirm reading that was brought up.

How about the "sock" on the end of pickup? Little strainer gadget might be collapsed and not allowing fuel flow. Maybe it's sucking closed after pump puts some draw on it? EDIT: No sock on these trucks.

Just some thoughts.

 

mine had the sock,i took the line off the top of the tank removed the gas cap and shot compresed air threw the line into the tank...sock gone works great.a couple other things to check,make shure there isnt anything like a shop rag in the tank. folks can be mean and when some one wants to mess with ya a rag in the tank will couse crazy problems as feul is suck threw the lines it draws the rag to the pick up tube closeing it off,another thing if theres trash in the filter ict can clog up and then settle down and fire up then reclog the filter

 

Take off your fuel filter. Mine would fill with tank rust until I got another tank.

 

You may have a check valve in the fuel pump that is not holding. Doesn't happen very often but it does just like a fuel line collapsing.

Just a thought.