fuel delivery problem

[K5dreamer]

So the truck has started to mess with me. It used to do this on a rare basis now it seems to be every time the truck starts.

I fire the truck up, and it runs long enough to empty the fuel from the IP and then stalls and dies. Get to do the crank, rest, and repeat until i can pull fuel back up to the IP and the truck fires up, and runs great as long as im actually driving it. has never stalled while driving or anything, just durring startup.

So im wondering what my likely culprits are here. I did find a melted/pinched closed vent tube from the fuel filter. So maybe i havent been venting air from the filter when i thought i was?

Off the top of my head, possible causes of fuel starvation would be.....

- fuel filter leaks. ive been told the factory brick fuel filter is kinda prone to leaks and causing hard starts. Several on this forum have suggested going to a spin on canister fuel filter to fix the problem.

- lift pump, im wondering if a leaking diaphram could still allow the pump to move the fuel to the IP while the engine is running, but possibly leak down while sitting.

- i have been running biodiesel (B20), perhaps the lines are leaking??

I did a quick visual inspection under the hood, but not along the framerail. the only wetness i could see was over the passenger side valvecover towards the rear where the fuel filter is. which kinda leans towards the leaking fuel filter deal. but its probably the original lift pump on the truck, so im wondering what the usual lifespan is on one of those.

 

[K5dreamer]

ok well, a new lift pump was only $28, as stated the old one is probably original, so it sure dosnt hurt to throw parts at it. I already bought the thing, probably put it on sunday, and see if there is any improvement. and replace that drain tube to vent the filter better.

also i looked around on the forum and found a thread where someone was complaining about their truck being a "dog", not having any power, and having a fuel drainback issue. and someone felt it may have been the lift pump.

also, for the length of time ive owned the truck, its only had about 1/3 usable throttle. the pedal moves when you press it. but there is no difference in engine sound, rpm, or performance, from 1/3 throttle to full throttle. I always figured i was bogging the engine, giving it more fuel than it could use, but im starting to think it was actually fuel starved, with the lift pump not supplying enough fuel flow for higher throttle. guess ill see sunday.