I have an 87 6.9L IDI. New injestion pump, fuel pump, and fuel filter. The fuel tank is building ALOT of pressure. When I remove the fuel cap (new) it sounds like your opening a shook up 2 liter of Coke, fuel gurgles up and out the filler neck, and white vapor. Also, it will idle forever but dies after driving it an 1/8 or 1/4 mile.
1. Has anyone had or seen this problem before?
2. How did you fix it?
3. Are they related?
Thank you.

 

Possible of a blockage in the fuel line

 

I figured out the 2 problems are related. Whatever is causing the tank to build pressure is causing the truck to die. The IP shuts down at 7+ PSI to keep from blowing any seals. So when the tank builds enough pressure the IP shuts down. But I am still unable to find out why the tank is being pressurised. If I back the fuel cap off a quarter turn or just enough to brake the seal of the cap on the filler neck it runs as long as you want it to.

 

need a new fuel cap with a good vent in it, sounds like vent is plugged on yours.

 

Truck already has new fuel cap. New IP. New filter. New pump. New glow plugs. New injectors. Its not just building a little bit if pressure. Its almost like the IP or fuel pump is pressurising it. is that possible?

 

I dont know how it would unless you are sucking in a bunch of air with the fuel pump, in which case, truck would not run verywell.

 

Its runs great if I keep the fuel cap loose.

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Actually in runs great with it tightened down for a minute or two then the tank builds enough pressure to shut the IP down.