Mechanical fuel pump replaced question

[fatahaunter]

I just got an 86 GMC K1500 with a Chevy 350 (not original engine). I ran it out of gas to see how large the tanks were and it completely died afterwards. I put more gas in the right tank, but it would not start. I tried putting some in the left tank and tried starting, and the fuel tank started leaking until it was empty. I got the truck home and replaced the fuel pump (the old one's lever wouldn't move). I replaced the fuel filter at the same time, but it was too small so fuel leaked out when I cranked the engine the first time. Fuel did reach it, though. I got the right filter but now gasoline won't go past the pump. What's wrong? How can I fix this?
Thanks in advance.

[zieg85]

Verify the fuel filter, assuming the stock one in the carb, is not put in backwards.

[fatahaunter]

Just tested, after cranking for a while, gas comes up the line. It isn't the stock carb, it is an edelbrock and it has a larger fuel filter, not one that fits in the carb or the line. It doesn't make it past the fuel filter, even though it is the same type as the old filter I replaced. Could the filter need more pressure than the pump is giving to get fuel through? Or do you need to fill the filter with gasoline in order to get any to get through it?

[jaredts]

So it is an inline filter, right?  Did you see a flow arrow on it and verify that is correct?

[fatahaunter]

It has 'in' written on it and I have that on the fuel pump side, though I have tried it both ways.

[bd]

Inspect the full length of the 3/8" fuel supply line and rubber hoses for perforations, cracks, general condition and leaks - pay particular attention to the hoses connecting to the right fuel tank and tank selector valve.  Try bypassing the tank selector valve by temporarily plumbing the right tank directly to the lines running forward.  Perform fuel pump draw (+20" Hg vacuum), pressure (5-7 PSI) and volume (~1 qt in 20 secs of cranking) tests.

[fatahaunter]

I was unable to get ahold of the pressure, vacuum or volume testers, but I got the warranty on the pump and replaced it again, still nothing. I put some gas in the line after the filter and some in the carburetor itself and it did start and run for two or three minutes until it died. I took off the line that lead to the carburetor from the filter, where I put gas in, and the line was full of gas. Did it stay on for the two minutes off of the tiny amount I put in the carburetor, or could it have died because of a clog in the tank that didn't allow any more gas to come? This is really strange, something I have never seen before

[bd]

Did you check all of the rubber hoses and steel lines running between the fuel tank, the fuel pump and the carburetor?

[fatahaunter]

I checked all the rubber hoses, there isn't a leak on the metal lines or anything obvious on the outside. When the pump first went out on the side of the road, i put gas in both tanks, to try starting it and see if the other tank would work differently, but the left tank (the one i didn't normally use) started leaking until it was completely empty after i tried starting the truck. Could a leak have formed due to the broken pump and that leak cause it not starting? If not, I'll probably take both tanks off and just clean them and replace the strainers and hope that works.

[blazer74]

Fuel pump pushrod was free to slide when you replaced the pump and the replacement pump was the same at the lever.

Fuel to the pump is a good flow?

Could try a small gas can with hose to the inlet side of pump. Place it above the pump for Gravity feed and see if the pump works.   

Eliminate to feed problem or pump problem.

Pull the ignition fuse if you like while doing this. Use a helper.

The hoses from the tank could suck closed if there bad also.



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[blazer74]

Do a pump test with a hose in a container from the pump, crank over the engine and see what u get.


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[bd]

How much fuel did you pour into the right tank?

[fatahaunter]

There is about six gallons in the tank now. I did do a gas can test twice. The first time, it cranked for about fifteen seconds and didn't start. The second time, I filled the fuel filter with gas and poured a bit in the carburetor. When I did that, I had a helper so I didn't wait until it died (if it would have died). I'll do it again and see if it lasts until the gas is gone from the can

[timthescarrd]

Inside the tank there is a mesh screen on the bottom of the pickup tube known as a sock. If you ran it completely out, it may have sucked 30 years of sediment onto the sock, thus not allowing enough gas to flow to the pump. as others have said, see if it will pump gas out of a small container instead of the tank

[roundhouse]

May be an issue with the cam that operates the pump lever
Might be time for an electric pump


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