acts like it's out of gas!!

[saltshaker]

car acts like its out of gas, but has a full tank! It will run for about 5 to 10 min and stall like its out of gas...I but a new fuel filter in checked the fittings at the fuel pump and all is tight. When then motor stalls the fuel filter is empty...motor has a mech fuel pump...had to be flatbeded home over the weekend...and Ideas...this has become fustrating!
Jon

[xlr8or]

Could be vapor lock.... try releasing the gas cap.

Are the fuel lines next to the exhaust?

[saltshaker]

I have tried running her with the cap open, but how would you get vapor lock with a vented tank ?
Jon

[PeteF]

I had a similar problem, and it turned out to be the fuel pump. One of the one-way valves in the pump came unseated (they were press fit in place). The car would start and run, but would stumble and die out occasionally. It was a Holley mechanical pump. Replaced pump, and now good as new. Your problem sounds like the pump, or some blockage upstream.....good luck.

[Tommy]

In the absence of more information about your set up, I'm going to make some assumptions before offering some ideas. First I'll assume you have a gravity feed line from the fuel tank to the mechanical fuel pump. Second, I'll assume the fuel filter is between the fuel pump and the carburetors. If these assumptions are correct, and your fuel filter is dry when the problem occurs, then you are either not getting fuel from the tank to the pump, or the pump is bad. It should be easy enough to determine if fuel is getting to the pump by disconnecting the line at the pump and seeing if fuel flows freely from the line. (Be ready to catch the fuel and do this in an open area where spilled fuel won't cause a fire hazard). If fuel is flowing freely to the pump, then it sounds like time to get a new pump.

[saltshaker]

the fuel tank has a pick up tube on the top of the tank which would mean thet the pick up goes from the top of the tank to almost the bottom...if I disconnect the fuel line at the pump (which I have) the only fuel that will come out is the fuel in the line not the fuel in the tank! I see nothing that would obstruct the flow of fuel in the path from the tank to the pump...I'm leaning towards a bad fuel pump!
Jon

[jhv48]

Could also be crap in the tank settling on the pickup screen then floating away once suction is relieved.

[Tommy]

Originally Posted by saltshaker

the fuel tank has a pick up tube on the top of the tank which would mean thet the pick up goes from the top of the tank to almost the bottom...if I disconnect the fuel line at the pump (which I have) the only fuel that will come out is the fuel in the line not the fuel in the tank! I see nothing that would obstruct the flow of fuel in the path from the tank to the pump...I'm leaning towards a bad fuel pump!
Jon

Apparently your fuel pump is higher that the fuel level in your tank. If it were lower, siphoning action would draw fuel from the tank even if the pickup and parts of the fuel line were higher than the fuel level. That's what I meant by "gravity feed."

[Tom Cimino]

When I read your post, the first thing I thougt was "I wonder if it's a Holley pump." I've had two Holley chrome pumps on my small block fail. First one broke the rod between the pump arm and the diaphram. Of course, dead on the spot. The second had one of the one way valves pop out and then got wedged back in. The motor stalled like it ran out of gas, but then caught and ran the rest of the way home. I found the valve wedged in it's seat kind of crossways but in enough to run. I quit fooling around and bought a Carter pump. Not chrome, but it's been working for over ten years. There's one bolt on the bottom of the pump. Remove it and the bottom plate and inspect the one way valves.

[Zoom This]

Yeh, I think I'd be drop kickin' the mechanical pump for starters and get either a different brand or go electric. Carter pumps are good and reliable. I've had an electric Carter in my Cobra for 6 years now. Keeps on ticking.

Bill

[glenview289]

Check your vents. With a clogged vent, you will build a vacuum in the tank that the fuel pump cannot overcome. With a full tank this will not take long because of the low air volume. The test of running with the cap off or open for longer than 10 minutes will verify this condition. The small hole in the LeMans filler could be plugged and some bug could have crawled in the tank vent line itself.

Bill

[saltshaker]

I thought about that, but when the car was filled over the weekend with to much gas the excess came out the vent tube leading me to think it is clear..
I just checked it and it is clear, disconnected the hose from the tank and could blow air through it.
Jon

[olddog]

I think it was said that the fuel line comes out the top of the tank. Also that when the fuel line was disconnected from the pump that the line emptied and that was all that came out.

If the front wheels were on a ramp or car jacked up then maybe the fuel pump and fuel in the tank were at the same level, however if the fuel pump is lower than the fuel in the tank it should siphon (gravity feed) regardless of how high the high spot is in the line. If by chance there was a loose connection or pin hole to allow air into the line near the high spot, it would loose its prime and the siphon would stop. You may want to add a length of line to get it to the floor and see if you can siphon gas out of the tank. If you cannot then that may be the problem.

[ratsnst1]

Originally Posted by Tommy

In the absence of more information about your set up, I'm going to make some assumptions before offering some ideas. First I'll assume you have a gravity feed line from the fuel tank to the mechanical fuel pump. Second, I'll assume the fuel filter is between the fuel pump and the carburetors. If these assumptions are correct, and your fuel filter is dry when the problem occurs, then you are either not getting fuel from the tank to the pump, or the pump is bad. It should be easy enough to determine if fuel is getting to the pump by disconnecting the line at the pump and seeing if fuel flows freely from the line. (Be ready to catch the fuel and do this in an open area where spilled fuel won't cause a fire hazard). If fuel is flowing freely to the pump, then it sounds like time to get a new pump.

when the car is turned of if u have a fuel presur gauge check it , key it of turn pump on , very simple, if not do it your self.