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Old 05-20-2014, 11:27 AM   #1
rushingad
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Question Intermittent Fuel Delivery Problem

I have been having a problem with the fuel delivery on my 72 K10 pickup with a 350ci. From what I can tell, gas is getting to the pump but not the carburetor when the problem occurs. The weird thing is that it may work for a week without a problem, but then one day it will just stop sending fuel to the carb, and may start back within 30 minutes or so of trying to crank and putting gas straight in the carb. I think it may be trash in the gas tank, because those old mechanical pumps usually either work or they don't. However when I pull the fuel line from the inlet on the pump, there is fuel coming out. It's not a ton of fuel pouring out but there is some fuel coming through the line.

Any Ideas?
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Old 05-20-2014, 08:51 PM   #2
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Quote:
Originally Posted by rushingad View Post
I have been having a problem with the fuel delivery on my 72 K10 pickup with a 350ci. From what I can tell, gas is getting to the pump but not the carburetor when the problem occurs. The weird thing is that it may work for a week without a problem, but then one day it will just stop sending fuel to the carb, and may start back within 30 minutes or so of trying to crank and putting gas straight in the carb. I think it may be trash in the gas tank, because those old mechanical pumps usually either work or they don't. However when I pull the fuel line from the inlet on the pump, there is fuel coming out. It's not a ton of fuel pouring out but there is some fuel coming through the line.

Any Ideas?
Likely no number of filters will cure problems coming from trash in the fuel tank. It'll always eventually pull trash up to the pick-up sock and interrupt fuel flow. But 1st, replace the short piece of flex tubing connecting fuel pump intake to steel line[if so equipped], as it can collapse when pump tries to suck fuel thru. Also, ensure the tank is not under a vacuum, often caused by ventless gas caps.
Hope you luck,
Sam
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Old 05-20-2014, 10:50 PM   #3
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Re: Intermittent Fuel Delivery Problem

I once had a japenese beetle floating in my fuel tank on my old 1969 TR6 DD, fuel level would drop just enough to suck her hard shell against the fuel line opening, but not always! Drove me nuts figuring that one out......
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Old 05-20-2014, 10:55 PM   #4
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Re: Intermittent Fuel Delivery Problem

if its a mech pump then pull the pump off and see how worn the lobe and the arm are.
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Old 05-20-2014, 10:56 PM   #5
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Re: Intermittent Fuel Delivery Problem

or a rubber line before the pump could be old and stupid and be getting sucked shut cutting off the fuel supply
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Old 05-21-2014, 04:27 PM   #6
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Re: Intermittent Fuel Delivery Problem

Last night I pulled the hose from the fuel pump and there was absolutely no gas coming out. So I shot some air down the hose and it started flowing out, so I'm going to conclude that it is trash in the tank. What is the best way to clean all of it out?
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Old 05-21-2014, 07:40 PM   #7
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Re: Intermittent Fuel Delivery Problem

The best way, if youve got a couple extra bucks, is to pull the tank and have it hot steam cleaned and recoated. that is the best way next to replacing the tank.

the cheaper side. 5 gallon tank of naptha is about 50 bucks, pour some in, you and a buddy shake the heck out of the tank and repeat 4 more times.

cheaper, baking soda or vinegar, same process as the naptha.
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Old 05-22-2014, 07:41 PM   #8
rushingad
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Re: Intermittent Fuel Delivery Problem

Should I just replace the tank?
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Old 05-23-2014, 12:44 PM   #9
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Smile Re: Intermittent Fuel Delivery Problem

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Should I just replace the tank?
If the tank is solid, and you've got patience and a helpful buddy, use the vinegar/soda technique, shake, rinse, and re-install. Personally, I lack many of those requirements and would hafta buy a new tank. The ultimate decision, of course is yours... Good luck, and congrats go to YOU on finding the problem in the 1st place!
Sam
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Old 05-23-2014, 04:46 PM   #10
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Re: Intermittent Fuel Delivery Problem

We always just took the tank out empty, put in some dishwashing liquid, couple of gallons of water and some medium sized gravel and shake it all about. Empty, rinse/repeat and if it comes out clean, you're done. Usually on an old tank it takes two or three times to get clean water coming back out.
You can get tank coatings that allow you to pour it in, tip the tank about until coated, dry and re-install.
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Old 05-25-2014, 08:01 AM   #11
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Re: Intermittent Fuel Delivery Problem

Some guys just remove the tank, drop a length of chain inside and shake and roll the tank about allowing the chain to knock any scale loose. Rinse thoroughly then use one of the tank coatings available.
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Old 05-25-2014, 10:09 AM   #12
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Re: Intermittent Fuel Delivery Problem

i would take it out and , call your local radiator shop and see if they can clean it and coat the inside
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