Fuel Pump question
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New User
Joined: Sep 2011
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From: WA
Fuel Pump question
hello friends,
im working on a friends truck for them. i am not entirely familiar with this old of a vehicle. its a 76 250 with the 460.
i just replaced the fuel pump on account of it randomly not pumping fuel to the carb. this truck has an inline clear fuel filter right by the carb. carb is an edelbrock something or another (not too sure) newer than the truck for dang sure
this filter is about 2-1/2' to 3" diameter and about 4"-5" long. before i changed the fuel pump sometimes it would take about 20 seconds for fuel to spurt into the filter. when it did its wonderfully convenient no-start there would be NO fuel spurting into the filter. then i changed the fuel pump. its still kind of random with how it fills the filter... but always does.
so heres my question(s): should the pump be keeping this filter full constantly or is it filled by demand of the carb? i do know that when the fuel level in the bowl drops the valve opens and fills it with fuel. so does this carry on to the fuel filter to? or should it always be full and all the way full???
just curious if i have some other issue(s) going on.
thanks for the help,
im working on a friends truck for them. i am not entirely familiar with this old of a vehicle. its a 76 250 with the 460.
i just replaced the fuel pump on account of it randomly not pumping fuel to the carb. this truck has an inline clear fuel filter right by the carb. carb is an edelbrock something or another (not too sure) newer than the truck for dang sure
this filter is about 2-1/2' to 3" diameter and about 4"-5" long. before i changed the fuel pump sometimes it would take about 20 seconds for fuel to spurt into the filter. when it did its wonderfully convenient no-start there would be NO fuel spurting into the filter. then i changed the fuel pump. its still kind of random with how it fills the filter... but always does.
so heres my question(s): should the pump be keeping this filter full constantly or is it filled by demand of the carb? i do know that when the fuel level in the bowl drops the valve opens and fills it with fuel. so does this carry on to the fuel filter to? or should it always be full and all the way full???
just curious if i have some other issue(s) going on.
thanks for the help,
Post Fiend
Joined: Mar 2011
Posts: 8,501
Likes: 4
From: Lynchburg, VA
Not sure about edelbrocks, but the stock carb has a screw-in filter where the fuel line goes in.
Junior User
Joined: Jan 2008
Posts: 81
Likes: 1
1) Stock the only filter is on the carb.
2) Metal lines run under the truck from gas tank to engine bay. With rubber tubing connecting the metal lines at the gas tank and engine.
3) It's a common addition to put a filter before the pump after the metal lines in the engine bay.
4) You could put a filter in at the tank, anything is possible so wouldn't hurt to take a look.
5) I just had a fuel problem myself and part of that problem was the fuel filter. It didn't look clogged but the paper had hardened and only let fuel through sometimes.
If it was me I would get a new smaller inline filter to put before the carb and add an additional clear filter before the fuel pump.
2) Metal lines run under the truck from gas tank to engine bay. With rubber tubing connecting the metal lines at the gas tank and engine.
3) It's a common addition to put a filter before the pump after the metal lines in the engine bay.
4) You could put a filter in at the tank, anything is possible so wouldn't hurt to take a look.
5) I just had a fuel problem myself and part of that problem was the fuel filter. It didn't look clogged but the paper had hardened and only let fuel through sometimes.
If it was me I would get a new smaller inline filter to put before the carb and add an additional clear filter before the fuel pump.
Mountain Pass
Joined: May 2004
Posts: 100
Likes: 0
From: Alberta
I had a similar problem once, the fuel hose between the pump and the carb was partially blocked, with something that looked like gasket maker, probably from a PO using it when changing the fuel pump, and making a mess. So, you may want to check that as well.
Senior User
Joined: Jul 2011
Posts: 215
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From: California
Heck, you may also be sucking air. On my 73 there is a rubber section of fuel line that connects the pump to the hard line, both sides of the tank switch to hardlines, and then the hardlines to the tanks, and a short section halfway in between that connects the front and rear hardline section together. One of the short rubber sections was cracked, so my pump was pulling air rather than fuel. I bought 5' of appropriate sized rubber fuel line and replaced all the short rubber connector lines in the system, just to be safe. I did this when I dropped my rear tank to fix the sending unit. I also have a clear-view filter before my pump and after I made these fixes, the air bubble disappeared.
Get yourself a fuel container and 5' of fuel hose. Hook one end to the inlet fitting to the pump and stick the other end into the fuel container and start her up. This should give you some info as to what to look into next.
Hope this helps!
Get yourself a fuel container and 5' of fuel hose. Hook one end to the inlet fitting to the pump and stick the other end into the fuel container and start her up. This should give you some info as to what to look into next.
Hope this helps!
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New User
Joined: Sep 2011
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From: WA
thanks to all for the help.
yeah i just was under the ol machine today and saw the short rubber section that connects the main tank to the hardline... cracked and spongy. i have mixed feelings about this: annoyance that i may have just replaced a perfectly good pump (luckily it was only $35) and relief that i believe i found the true culprit. should have done a little more looking around first... lesson learned. now to replace it and find out.
yeah i just was under the ol machine today and saw the short rubber section that connects the main tank to the hardline... cracked and spongy. i have mixed feelings about this: annoyance that i may have just replaced a perfectly good pump (luckily it was only $35) and relief that i believe i found the true culprit. should have done a little more looking around first... lesson learned. now to replace it and find out.
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Senior User
Joined: Jul 2011
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From: California
Yep, spend some time under there replacing all those old rubber sections and you will probably find other stuff that needs attention as well. I discovered both the filler necks for my tanks were cracked and leaking as well. I blocked out a weekend and dropped the tanks and replaced both my sending units, all the rubber hoses, the filler necks and the gas caps. I have ZERO fuel issues now and I can worry about other things 
Good luck with the project!
Good luck with the project!
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