Technical Is my mechanical fuel pump bad?

I have a '69 Ford 302, with the usual upgrades in my car. I replaced the original fuel pump 13 years ago and the the car sat until last summer. The car will die, seems like it runs out of gas while cruising along at 40-50mph. Eventually it will restart and then repeat. I have clear Fram fuel filters both between the pump and Holley and also one at the gas tank. Today I had the car idling to see what I could see and I noticed that the filter by the tank would fill up about 75% and then run dry and after a few seconds it would fill with gas again and then empty, then repeat. Is this right? Shouldn't the fuel flow be steady?

Any suggestions? TIA

 

Replace the pump. Shit, it's been 13 years, replace it even if it's not the problem.

 

Whats the filter at the tank for? Lippy

 

13 years and ethanol probably eat up the diaphragm. Pumps are cheap, buy one !

 

If its bad make it stand in the corner until it behaves...

 

Why are you being so careful as to not mention what the hell kind of car you have???
Hell,in 13 years,it probably needs about everything.

 

Lippy, the filter was found when I pulled the tank last year. It appears to be original equipment. It had "replace every 5000 miles" printed on it. The car had 43,000 miles on it at the time.

wbrw32, it is a OT car that most have probably never heard of. It has sat 35 of it's 47 years. The issue is the fuel pump/engine, not the car. This is where the most experienced people that I know of hang out, so I asked the best.

 

I replaced the fuel pump, but the fuel flow is just as intermittent as it was before. Any ideas?

 

If you don't have an electric pump you really don't need the filter between the pump and the tank. If the filter is below the tank once you start pumping fuel it should stay full. You could probably use a new pump but you make also have a problem at the pickup in the tank and I would be thinking about that as well.

 

There probably is a "sock" on the fuel pick up tube in the tank that is probably rusted or full of crap in the tank....

 

The filter is at the top of the tank. The pick up is clear. I drove the car from Wisconsin to California and back in 2000 at about 75mph with no problems. Now it seems to run out of fuel, even on city streets. Weird.

 

replace the rubber sections of the fuel line at the tank and motor. 13 years of siting would be a problem.

 

There should be a filter"sock" on the end of the pickup tube inside the tank. I would take the fuel line off the input of the pump and blow air through to the tank, to see if there is a restriction, also could be sucking air.

 

I've replaced most of the rubber fuel lines and have had the tank pickup out several times. It's OK. Also had the tank cleaned last year.

 

Is there a filter in the carb?

 

yes. A new one.

 

This sounds to me like it is either vapor locking or the tank vent is plugged. The next time it acts like it's starved for fuel take the fuel cap off and see if that helps.

 

It does have a vented cap and I watched the fuel flow with the cap removed, but no difference.

 

Maybe it's the carb ?

 

cap vent probably has a mud dauber wasp nest plugging the hole or rust , quite common

 

Is the carburetor a Holley?
What part number is it?

 

That filter on the suction side should stay full unless there is a way for air to get in between the filter and the pickup in the tank. If there is always an air bubble in it, that bubble will get bigger when the pump is sucking and smaller when the needle valve closes so the pump isn't moving fuel.

 

If you haven't tried testing by removing the tank to pump filter,,,,do so. I don't see a reason for it to be there.