fuel pump?

After an hour of driving and climbing a hill, my 74 cj5 w/304 starting lurching and died. It felt like a fuel/air problem. Is there a situation where the fuel pump may not be working "well enough" in certain situations? Glass fuel filter seems fine. Also, the po didnt use check valves on the fuel lines.

 

Could be.

Check valves? :? There are check valves in the fuel pump. No other check valves.

What ignition system do you have, the original Prestolite? It is known for just quitting, and then recovering on its own. Drive down the road, and the engine stops and won't restart. Pull over raise the hood, and walk around the car. Close the hood, get in and drive off. Typical.

 

I thought there was a check valve at the tank. Anyway, I have an aftermarket ignition. I can always restart the engine after it stalls by standing on the gas. It just wont stay running. If I let it sit for 30 min, it starts and runs fine.

 

That check valve is for vapor recovery - nothing to do with fuel delivery. If present, that valve is under the left rear fender. If your fuel tank is vented to the air (ie no charcoal canister, or a vented gas cap), that check valve does nothing.

Check for fuel pressure delivery - the TSM has a procedure.

Vapor lock is a possibility. Lots of discussions of that in the past, if you search.

 

Ok, I've checked the vapor lock threads, and forgot to mention that my fuel pump isn't working as a check valve. Fuel drains back into the line after sitting for a while. I know this because I have a glass fuel filter. So im still guessing on a poorly operating pump. Opinions?

 

hot start and standing on gas... black smoke on restart? sounds like heat soak causing the fuel to expand in the bowl and flood the engine. a phenolic spacer would prolly help by isolating the carb from the manifold heat ive seen some with an aluminum shield under the carb too

 

I have run compressed air into the fuel pump (in the direction that fuel flows) and blew junk out from the check valve and restored the fuel pump back to normal. The fuel is not supposed to bleed back. If it does then your pump is not able to supply the proper pressure and volume.

 

The fuel should not flow backwards through the fuel pump. And the float bowl will not drain on its own.

A common problem is sediment in the fuel tank holding the one-way valves in the fuel pump open. You can put an additional fuel filter before the fuel pump to catch any sediment, but the best solution is to clean out the fuel tank. I'd just replace the pump and toss the old one into the spares pile.