Engine starts but then dies

[abfiegen]

So I drove my truck on a 500 mile round trip a week and a half back. Ran great. I decided to start it up cause it had been over a week and I'm still learning all the quirks it has. It started up good, but then died. I assumed air musta leaked into the fuel system so I turned it over again. Started up a little slower than previously but then it died again. Turned it over a third time and it started and died again.

Came back the next day to start it and lay on the pedal a bit after it gets going, but this time it wouldn't even start up. I cracked two unions and turned it over again. It started after 5-10 seconds of cranking and went to high idle but then died. Tightened the unions down again and tried to start but couldn't even get it to sputter. I'm a bit dumbfounded by this and it leaves me thinking it might be something besides or more than an air leak problem. It hasn't historically had any air in the fuel system besides self-imposed issues.

One thought a friend of mine had is that the fuel pump for a particular tank crapped out on me while driving and the injector pump was pulling fuel all the way from the tank to the injectors. Then when it came time to start again it wouldn't build enough pressure. But it's been starting and dying so that makes that thought iffy at best to me. Is the injector pump even capable of doing that?

Anyone have thoughts on this problem? Thanks in advance.

 

[cpdenton]

Take off the fuel filter and see if it is filled up or partially empty.

If it is full, you should have fuel at the IP. I suspect it will be partially empty. It could be that way for a number of reasons.

Air intrusion draining the fuel back.

It could also be the lift pump. Our trucks do not have fuel pumps in the tanks. Just one lift pump on the lower passenger front of the engine. It might be failing.

 

[abfiegen]

I had assumed there was a pump in each tank. If that is not the case then what does the fuel tank switch fundamentally change?

 

[cpdenton]

Fuel tank switch operates a servo that changes a valve between the supply and return lines of the front and rear tanks. It also changes the fuel level sender signal wires.

 

[79jasper]

Your buddy sounds like a dodge guy.
These pumps absolutely will not pull any fuel.
Try running a jumper straight from the battery to the IP shutoff.
Does sorta sound like a fuel delivery problem. If your tanks are below or around a quarter tank, the pickup screens are probably broke off in the tanks.

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[abfiegen]

When I cracked the unions it did start. And they were wet with diesel. So fuel is going to the injectors. It seems to me to be a matter whether it is getting enough fuel. Does this seem like an accurate assessment?

Haven't had a chance to check the fuel filter yet.

 

[83ford]

If your filter is partially full it may be the lift pump or it could also be the selector valve I've had 2 go out on me but mine would idle but driving it kept dying and it had no fuel to schrader not even air.so also crank it and see if fuel comes out


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