1977 f250 4x4 w/460. Is it possible for a fuel pump to work intermittently? Pump is new. Lines are new. Tank had been clean

 

Tank has been cleaned. When first started, see-through filter is full of fuel. As it idles, fuel level drops, motor dies. After several restarts/idles, fuel filter remains full at idle or increased revs. Let it sit for a while and I have to start all over again. Is this because of the fuel pump?

 

That's certainly a possibility; another possibility is air making its way into the lines.

 

Usually a mechanical fuel pump either works or doesn't. X2 on sounds like an air leak. Ck all your soft rubber lines/connection points clamps.

I have never seen a clear fuel filter stay completely full. Sending unit new? Any chance intake screen on end of sending unit is clogged?

Sounds like maybe vapor lock? Take your filler neck cap off...and see what happens.

All you carb vacuum lines connected properly?

 

All lines are new. Checked all clamps/connections. Tank is clean. Sending unit is new. If the system was getting air somewhere, wouldn't I see fuel leaking out? Didn't think to check vacuum lines? Will try taking gas cap off in the morning.

 

Which vacuum lines have an effect on whether fuel gets to the carb?

 

What kind of carb and if aftermarket, do you have a vacuum line connected?

 

Is the fuel filter actually emptying, or are you just concerned that it's not full all the time? As said above, there's nothing to say it actually has to stay full. In all honesty, clear fuel filters lead to more confusion and false troubleshooting than they help.

Asked another way, how do you know the engine is dying because of a fuel delivery issue? Have you checked for fuel when it dies? Meaning, do you see fuel shoot onto the venturi's when you pull the throttle back after it stalled? Have you checked for fuel in the bowl? If all you're going off of us a drop in fuel level seen in the filter, you're probably chasing your tail. Unless you're saying the filter completely dries out.

 

Fmc400, fuel filter actually dries out with no fuel flow coming in. Truck dies. When I get time today, I'll let you guys know which edelbrock carb I have. I can't remember right now.

 

....with "fuel injector" quality line.

 

Please read all information before posting. I put all NEW fuel line in.

 

Sorry if I sound rude. I don't like repeating myself. Not sure if its fuel injection hose or not. I think its regular 3/8 fuel line.

 

Well, that gas has to be draining back somewhere....to make sure it's not getting into your oil, pull the dipstick and take a good whiff. Hopefully, there's no gas smell or indication of gas in your oil.

I know you'll probably jump on me, but I, too, would recheck the soft and hard line connetions for tightness. The pump could be sucking air without leaving a smell of gas. Since you stated the pump is new, I would start at those connections.

You could also try taking off the input to the pump and check for (gravity) flow (cap off), if you have the space and the tank elevation is high enough. If not, some air (5 -8 psi) blown into the tank and with the other end in a container, some unobstructed flow should be evident.

And, yes...it's possible a "new" pump could be faulty from the gate.

 

Checked the oil. No gas smell. Carb is an Edelbrock 1411 w/electric choke. Gas gravity feeds at all points from tank to carb. Picked up a new pump for kicks and giggles. Will install tomorrow.

 

New pump. Same issue. Bummer. Quick question about fittings. Does a flared hose end need an o-ring?