Running out of fuel

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schmitt

schmitt

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Hey guys,
Had to take the fuel sender out of my Old D100 being it was leaking. Added a new gasket and got it sealed up.

However I take the car for a spin and it shuts off like it runs out of gas. Check the carb sight glasses and sure enough its dry, turn the key to let the pump run and carb fills right back up, Away I go until the carb runs out again. Shut it off and then back on with the key let the electric pump run and fills up again.

Is my pump just going bad and it just so happens to be when I had my sender out? Or am I missing something?

Thanks
 
Are you sure the rubber hose is sealing. After disturbing an old rubber hose its possible for it to suck air.
 
Rubber hose? The return line is tight if that's what you mean? Also the sender has a metal pick up tube and I made sure that was tight too.

The pump seems really loud and my fuel pressure gauge seems to be jumping around a bunch. Not a nice steady pressure.
 
Are you sure you have enough gas in it. The noisy pump and erratic pressure is either low fuel or sucking air in my experiences.
 
500 DUSTER said:
Are you sure you have enough gas in it. The noisy pump and erratic pressure is either low fuel or sucking air in my experiences.
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Yeah I just added another 5 gallons tonight to make sure.
The pick up tube on my sender goes straight to the top and connects with a -AN style fitting and has a 90 off the top for the braided line to hook up.
 
Is this the old tank behind the driver's seat? I would help a ton to describe all the parts in your system since it is not an A-body.
 
Yes sir it is, Behind the seat tank.
Like I said pulled the sender because the seal was leaking and I was getting gas fumes.

Sender goes with metal line to canister style cartridge filter then -8an to Holley black pump, -8an to fuel press regulator, -6an carb feed lines. Pro-systems Holley
 
All I can really show

image.jpeg
 
Hmmmmmmmmmmmmmmmmmmmmmmm that's a toughie. I think the answer is in this thread somewhere.How high/low is the pump mounted relative to the current fuel level? My recollection is electric pumps mostly can't suck up hill much. They are real good at pushing tho.

and FWIW, don't take offense but your coil location scares the heebie-jeebies into me.Just a tiny bit of bad luck could get real expensive, really fast.
 
AJ/FormS said:
Hmmmmmmmmmmmmmmmmmmmmmmm that's a toughie. I think the answer is in this thread somewhere.How high/low is the pump mounted relative to the current fuel level? My recollection is electric pumps mostly can't suck up hill much. They are real good at pushing tho.

and FWIW, don't take offense but your coil location scares the heebie-jeebies into me.Just a tiny bit of bad luck could get real expensive, really fast.
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Pump is down on the frame so downhill for sure. Wasn't having a problem until I worked on the sender (sealing it to the tank). But I can't think something could be wrong with that. Just dumb luck my pump would go out right after?? Idk

Not sure what you mean about my coil
 
I don't know. But if you read about ANY service manual from say, 67---7?? or maybe 8?? there's a procedure in them for checking the pump and fuel system. This includes checking the pump with a vacuum gauge, checking the pump for volume. Other than that, you need to start at one end and go to the other


1...Problems with the pickup, including gummed up filter sock, or on some vehicles, the sock has a flat tin bottom which can suck against the tube end

2...Collapsing connector hoses at the tank and the pump

3...Dirt, rust, debri in the supply tubing, or PINHOLES in the line allowing air into the line.

4....Plugged filter after the pump. Don't forget some carbs have filters in the carb inlets.

"Rig" a pressure gauge right at the carb and see what you have
 
So then where is the pump being fed from; A) the bottom of the tank or B)from a standpipe through the top.
If standpipe, then perhaps your pump has lost it's prime.Like I said, electric pumps don't like to lift the fuel.
If from the bottom, I would suspect something has drapped over the sock.

Here's a test; disconnect the fuel line from the carb, and run it into a jerry-can, on the shop floor, or some point lower than the pump.Turn the pump on and run it until no more air comes out, and then clamp the line. Reinstall the hose to the carb. Remove the clamp. Turn the pump back on and drive.
 
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AJ/FormS said:
So then where is the pump being fed from; A) the bottom of the tank or B)from a standpipe through the top.
If standpipe, then perhaps your pump has lost it's prime.Like I said, electric pumps don't like to lift the fuel.
If from the bottom, I would suspect something has drapped over the sock.

Here's a test; disconnect the fuel line from the carb, and run it into a jerry-can, on the shop floor, or some point lower than the pump.Turn the pump on and run it until no more air comes out, and then clamp the line. Reinstall the hose to the carb. Remove the clamp. Turn the pump back on and drive.
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It could be I lost prime?? The sender just has a stand pipe from the top of the tank that goes down into the tank. So option B.
 
I went through something similar with a w150 and a 32 gal tank. The round plug on top of the tank for the sender and pump was intermittent at times. Good luck finding a new one if that is it. They ALL collect water there it seems.
 
halifaxhops said:
I went through something similar with a w150 and a 32 gal tank. The round plug on top of the tank for the sender and pump was intermittent at times. Good luck finding a new one if that is it. They ALL collect water there it seems.
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I just have one wire going to the sender for the fuel gauge.
 
schmitt said:
Yes sir it is, Behind the seat tank.
Like I said pulled the sender because the seal was leaking and I was getting gas fumes.

Sender goes with metal line to canister style cartridge filter then -8an to Holley black pump, -8an to fuel press regulator, -6an carb feed lines. Pro-systems Holley
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Finally a little info! I cannot STAND the Holley "color" pumps. They are loud as hell and don't last near as long as they should. -8 line? Seriously? Is this a drag truck? What's your return system? If you're dead heading, that could be the issue. Holley color pumps despise being dead headed. They overheat and quit pumping.
 
RustyRatRod said:
Finally a little info! I cannot STAND the Holley "color" pumps. They are loud as hell and don't last near as long as they should. -8 line? Seriously? Is this a drag truck? What's your return system? If you're dead heading, that could be the issue. Holley color pumps despise being dead headed. They overheat and quit pumping.
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That's what pro-systems wanted me to run. Can call the truck whatever you want.

Return comes off Holley regulator with -8an all the way to tank
 
schmitt said:
That's what pro-systems wanted me to run. Can call the truck whatever you want.

Return comes off Holley regulator with -8an all the way to tank
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I wasn't sure what to call it to tell you the truth. I saw D100, then you said "car" so it made me wonder. Then finally at post #8, we learn a little about what you're workin on. What HP are you trying to support? That fuel system will support 1000 HP.

And of course "they" want you to run it. It costs a lot of money. lol
 
RustyRatRod said:
I wasn't sure what to call it to tell you the truth. I saw D100, then you said "car" so it made me wonder. Then finally at post #8, we learn a little about what you're workin on. What HP are you trying to support? That fuel system will support 1000 HP.

And of course "they" want you to run it. It costs a lot of money. lol
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About 1025 at the crank
 
OK so you have a stand pipe. Well the standpipe must have a flexible connection to the sender right? If there is the slightest chance that the pump can suck air, then it will rather pull that up than fuel. It will then cavitate, and be noisy and get hot if this is allowed to continue.
I suppose the standpipe itself could have a hole in it somewhere above the current liquid line.
I suppose that if the problem was to go away with a full tank, then the pump has primed itself, and any hole in the in-tank system will not show up until the liquid level falls below the height of the hole.
 
schmitt said:
-8an. Maybe my fuel line is actually to small for 1025 Hp then?? Hahaha
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You said it goes from -8 to -6 at the carburetor and then -8 is the return. Is that right? What style and brand regulator?

I don't think any of that is the problem, but you never know. My thinkin is the pump is WAY not enough. You need something like one of those badass Mallory gerotor pumps.
 
AJ/FormS said:
OK so you have a stand pipe. Well the standpipe must have a flexible connection to the sender right? If there is the slightest chance that the pump can suck air, then it will rather pull that up than fuel. It will then cavitate, and be noisy and get hot if this is allowed to continue.
I suppose the standpipe itself could have a hole in it somewhere above the current liquid line.
I suppose that if the problem was to go away with a full tank, then the pump has primed itself, and any hole in the in-tank system will not show up until the liquid level falls below the height of the hole.
Click to expand...


Stand pipe has no hose, just a -An style nut that hooks to the underside of the pictured blue 90degree fitting

image.jpeg
 
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