I know there are alot of these, but none match my problem. This is long so I will try to keep it as short as possible. My son and I bought a 4spd 76 L48 that was almost junk for next to nothing 5 years ago (he was 13 then).

We finally got the car on the road about a month ago. It would run great in the garage, but when we started driving it, it would skip and sputter and hardly run. There seemed to be bubbles in the inline fuel filter and very little fuel. This is the setup and what we have done to try to fix it.

The car -- it has duel electric fans and no mechanical fan or shroud ( never runs over 205 ). The engine seems to generate a great deal of heat -- we did not rebuild it (matching #s). The car sat for 25 years ( last inspection was in 1985 ).

We put tight tuck headers and dual exhaust all the way back. The headers are wrapped.

We dropped the tank and cleaned it out, blew through the lines and filled it up with gas. This made it a little better, but would stall while driving at a steady speed after about 15 to 20 minutes.

We replaced the mechanical fuel pump with the Mr. Gasket version of the Holley Blue ( 105 gph ) and a regulator with return. We insulated the fuel lines the best we could where we could. This might have helped a little more, but still stalled after driving for a while.

I put a new Holley 4160 carb with elec choke on and that made it run great ---- until it stalled again. It runs great then starts to hesitate until it stalls. After it stalls and you stop it will start right back up and run a while before it stalls again. When it stalls and you turn the key back on the fuel pressure is 0 - 1 and there is little or no fuel in the filter. It will start and run fine and the pressure builds to around 8psi.

Before you say ignition -- I just put a new Accel 59107 distributor on and set the timing to 9 b tdc and ~ 32 total. Oh yea -- it has new 8.5 Accel wires and new plugs. It still stalls while running at steady throttle ( rpm does not matter ) after about 15 mins at operating temp. Starts and will run immediately

The fuel pick-up is original in the tank ( top feed ). I have considered converting to bottom ( gravity ) feed.

There seems to be alot of heat under the hood, but it never overheats. I don't know how I could isolate the fuel lines from the heat any more and keep them in the car.

25 to 30 psi oil pressure, little or no smoke, and vaccum is 18 to 20 at carb base.

I NEED HELP --- IDEAS

 

forgot to mention that it might be worse when tank is below 1/2 full. Pump is below tank in the rear.

 

you say after it stalls that the pressure is 0-1 and there's no fuel in the filter? i think that answers your question. my "guess" is that you have a partially clogged line, a out-of-the-box bad pump, or electrical problems to the pump. with a properly operating electrical pump, even with vapor lock you would have more that 1 psi in the lines.

 

That is my initial thought also. The confusing part is that it will start right back up and run fine for a while then the same thing again. There could be a problem at the sending unit and the low fuel level reduces the ability to siphon to the pump. I did just find that if I shake the power wire to the distributor hard it will cut off and then start again. This does not explain the fuel pressure problem when it stalls

 

skake the power lead to the distributor? do you have the pump fed form the distributor? if so, that's your problem. you're only getting 10 volts to the pump, and even then on a bad connection. as a test, run your power from the horn relay, and see what happens. if that solves the issue, either run a lead from the "ing" lug on the fuse panel, or (not as good) a lead from the distributor as a coil feed to a relay. then use the output of the relay to power the pump, the relay will opperate on as little as 9 volts and only draws about 1/10 amp.

 

No No sorry for the confusion. The pump is powered through an ignition controlled relay. I do not have it running through the oil pressure switch ( to eliminate that from being the problem ). The pump is getting 12V when the key is on. The power wire is from the battery through the ignition to the HEI Distributor. When I shake it hard the ignition is cutting out causing the engine to stall.

 

If you have a very small air leak between the pump and the tank, it might start sucking air when the vacuum in the tank builds up. Try running with the gas cap loose so there won't be a vacuum in the tank.