Zero fuel pressure, car won't idle

[Nate Yi]

I have a 440 from a '79 motorhome with a Eddy Performer 750 carb but for some reason it's not seeing any fuel pressure. The car ran a week or so ago with absolutely no problem and healthy fuel pressure with the stock Thermoquad before it started having the problems it's having now. I thought it may be a carb issue so I bolted on an Edelbrock Performer 750 I had around and the engine still won't see any pressure.

I thought it was the fuel pump because my fuel pressure was reading zero. I filled the carb bowls up so that it would run for at least a little bit and pulled the fuel line off the carb. The car would idle after spraying it with some starter fluid but the fuel would just sputter out of the pump line at idle and completely stop flowing under throttle.

I replaced the Airtex that was on it and then I put a Carter on it. It is still having the same problem, even with the new pump. I removed all filters, made sure the lines were clean, made sure the tank was full, but the fuel is still not flowing as it should. What else could it be?

 

[72 Charger SE]

Could be plugged at the pickup in the fuel tank. I had the same problem after my car sat for several years. The sock on the pickup tube was clogged with rust scale from the inside of the fuel tank. I replaced tank and sending unit rather than mess with trying to get all of the rust scale out of the tank - problem solved.

 

[Nate Yi]

Well, I pulled the pickup a couple weeks ago and it was clean. I also cleaned the inside of the tank out and treated it. The fuel pump push rod also seems straight, as I slide it in and out freely.

 

[Nate Yi]

Well, I dropped the gas tank last month and cleaned it out. I also cleaned out the fuel sender and ripped the sock out.

 

[Histoy]

Did that fix the problem? If not, you may have a bad flexible hose in the system.

 

[Nate Yi]

Ah! Silly me. Turns out the fuel sending unit is completely plugged up with something. I put a line directly from a gas can with fresh gas to the fuel pump and she ran like a champ. One weird thing is that with the Carter pump I'm only showing 2-3 PSI, whereas with the Airtex I was pulling 5-6. Could that be a difference in the pump brands or the fact that I bypassed the fuel tank, sender, filters, and lines completely?

 

[Cranky]

Different fuel pumps can put up different pressures but both need clean open lines to receive full fuel flow in order to put up their max pressure. Do you have a filter before the pump? Without a sock in the tank, you should have a high flow filter somewhere before the filter. If you've ever worked on a fuel storage tank at a refinery, you'd be amazed at the junk inside those things....then you have the tanker trucks that bring it to the gas station's storage tanks....you get the picture. They have filter systems but it's designed for flow and doesn't get everything out.

 

[70WM21 W1 V6B]

You may also while you are at it recheck the fuel pump drive rod as they do wear out and get "Shorter" and not depress the fuel pump arm fully. They will still slide in and out, but I have seen some that wore out so bad they no longer pumped! Easy to change , fairly cheap and I think still available from your local Chrysler dealer.

 

[kelly]

would a wore out pump drive cause the pump to work then not work? I'm having problem like that and everything is new or blowen out. lines that is.
Thanks

 

[PP1RT]

Everything is suction before the pump. A rubber fuel line may look fine and blow thru fine but collapse on the inside when pulling fuel thru. Change any rubber lines you have. Let us know what happens.