LB7: New to forum w/ fuel problem

[mccavr]

Hello everyone. New to forum here and hoping for some help. '03 Sierra's batteries finally died yesterday morning (been nursing for a little bit) so the truck wouldn't start. Put new batteries in today and truck fired right up, ran for about 20 seconds then died. Went and checked the fuel primer pump and it was soft (like when it's run out of fuel), primed it and it started right back up but then died again. Obviously not getting fuel, but is it the pump or something else? Any thoughts would be appreciated.

 

[battlegraduate09]

Any modifications on the truck ? Any trouble codes? A good scanner would be handy in this situation, but for the time being you can check the fuel lines from the fuel filter head going to the FICM and the into the valley of the motor for leaks while your pumping it, and while the primer bulb is hard. If you have a guage you could hook to the fitting on the passenger side of the motor that would see how much pressure you are actually building by pumping the primer bulb and see how long it takes to drop the pressure before you start the truck.

 

[Josh2002cc]

How cold is it up there? Are you running mixed fuel from the pump and or do you add treatment to prevent gelling?

 

[mccavr]

Only mods to the truck are intake and exhaust. I checked for leaks and didn't find any, primer bulb stays hard after it's primed. I don't know much about the fuel system but when the truck starts I can keep it running smoothly by pressing the primer bulb every few seconds. Once I stop priming, truck shuts off after about 20 secs. How can I tell if the fuel pump is bad? Excuse my lack of knowledge.

 

[mccavr]

It was about 25 deg F yesterday, and yes I do run PS diesel fuel supplement. I know the cold is what finished off the old batteries and why it wouldn't start yesterday, but it was about 40 today and it fired right up after the new batteries.

 

[battlegraduate09]

what about the o ring in fuel filter head ?

Your truck doesnt have a fuel pump, has a CP3 in the valley with a fuel pressure regulator on it.

 

[mccavr]

i'll check it

 

[tgebes]

Rebuild the filter head, its $20 for the kit and eliminates the possibility.

 

[dracing70]

or better yet throw a lift pump with a 2 micron filter system on and eliminate the stock filter head all together

 

[TLyons90]

X2 on rebuilding your fuel filter head! Tis what it sounds like...

BTW welcome!