2nd Gen Non-Engine/Transmission Hard start below 1/4 tank

[dknoch]

Hello, I have been chasing a hard start issue for awhile now. Last year I had a hard start problem that turned out to be a fuel gauge sending unit. Classic symptoms: nose up+ sitting for a few hours=hard start, nose down could sit for weeks and be fine. Had a new FASS titanium installed this past winter due to pulsing pressure on my old FASS. Started having a hard start issue but only below 1/4 tank. Hard start issue got worse and turned into a any level tank hard start. Replaced injector o-rings and crossover tubes with new o-rings and now I am back to hard starts only at or below 1/4 tank. Anybody have any ideas??? Thinking of dropping the tank and inspecting the fuel module. Suspecting that the fuel return line in the tank may have an issue since at 1 point I disconnected the return line, blew compressed air into the tank through the return line looking for leaks and when the tank decompressed I got a face full of AIR, should have been fuel if the end of the line was submerged. It was at 1/4 tank at the time. I also question the FASS and may change the filters on that in case the separator is sucking air but hate to waste a good filter at what they cost. Thinking of a dual port Hellmann Sump as a last resort for the supply and return line.
Thanks, Dan

 

[jeepit]

Are you sure the sending unit is reading correctly? I would fill the tank and see how many gallons of fuel you can get in.
Pickup tube may not be to the bottom of the fuel module.
Did you install a draw straw?
I wouldn't run a sump. I have a modified Vulcan fuel module that solved all 1/4 tank issues I had.

 

[dknoch]

Thanks for the reply. The hardware in the tank is OEM and the fuel level reads about right based on the amount of fuel needed to fill up at the pump. I like the Vulcan module modification, just not sure if my issue is with the return line.

 

[Houser]

Might just need to tighten up all your fuel lines some times
They develope air leakes

 

[dknoch]

Thanks, I have ordered the Vulcan fuel module, should have it next weekend. I have checked all the lines multiple times. At about 1/4 tank, it is like a light switch. I am guessing it is either in the module or at the level of the fuel system when the tank is at 1/4 tank. This would be my FASS and an inline cooler (fittings are nice and tight, no leaks noticed).
Last year my leak was at the fuel pressure sender but it never spit fuel out, just sucked air in at rest. My 1/4 tank issue seemed to start with my new FASS, and progressed into a full tank issue that has been turned back into a 1/4 tank issue with new injector o-rings. That was a hard start anytime it was pointed up hill. Not too much left to replace at this time. I will let you know if the module fixes it. Hoping So!

Dan

 

[4570]

Does your truck still have the mechanical fuel pump that you can pump up by hand ? If so when you think its going to start hard ,raise the hood and pump till it gets hard to pump and see if it starts right away .My 96 had a leaky return line and by hand pumping it started right up every time .

 

[JR]

Unfortunately mechanical lift pumps went by the way side in 98.5 with the introduction of the VP44.

 

[dknoch]

Well, have had the Vulcan modified fuel module in for a week now. Ran it until the fuel light came on and no issues. Sat out over night with the nose up and started fine. Had some trouble with the tank venting so i installed an aftermarket tank vent/rollover valve from Tanksinc into the fuel filler tube using the old adapter from the FASS. No more "woosh" sounds when I open the fuel cap and pressure is up a pound or more compared to before the vent.

. Time will tell if this takes care of the issue or not. Thanks for the help with stuff.
Dan