Engine/Transmission (1998.5 - 2002) Hard Starting 98.5 24 Valve, VP44

[AFaustini]

Recently replaced the VP44 with a new check valve and copper washers, installed a fuel pressure gauge, and a air dog FP100 fuel pump/filter system. Since I replaced these items, truck hard starts after sitting for a while#@$%!, when I crank it up though fuel pressure gauge hovers around 14 to 15 PSI. idle and around 11 to 13 WOT. One thing that concerns me is when it's running the fuel pressure gauge is not steady, it jumps around about a half of pound of pressure or so, is that normal? I have revisited all my connection points and found no leaks even going as far to install hose clamps on all the push on fittings. Removed both quick disconnects from the fuel tank and installed supply and return fuel lines straight to fuel tank barbs with hose clamps. Checked the allen screw in the air dog pump block for a leak and found even after installing thread compound on it. When truck is going down the road it runs like a champ, it's the hard starting since I replaced the factory lift pump and filter that is driving me crazy. Any help will be greatly appreciated as you all on this site are great and trust me my truck and Geno's Garage is better for it. Seriously though, thanks for any advice in advance and Geno's garage has been great to do business with.

 

[blacksheepdiesel]

Welcome to TDR land!

You mentioned you checked all your connection points on the fuel lines. Did that include the return lines and hose? If there is a bad connection on the return side it can cause a hard start. Also, describe hard start?

Godspeed,
Trent

 

[tplewis]

hard starting

i know this sounds crazy but try unplugging your lift pump and see if it will crank the computer on the engine is supposed to cut voltage back to the lift pump during cranking position it can be bad and cause a hard start i just had a truck in my shop do this last week if unplugging lift pump fixes your problem e-mail me and i,ll tell you what i did to make it crank without the very expensive computer -- email address removed --

 

[SHuber]

tplewis is on the right track, when I installed my fass unit the directions said that after installing it if you end up with a hard starting issue then unplug the lift pump and see if it'll start, if it starts then you are probably ..... dare I say on the verge of a new VP44. Apparently when the VP44 gets starved for fuel then the diaphragm in it will move too much and start to tear. Then when you put the new lift pump on the fuel just goes through the diaphragm. I aint no expert on VP44, about the only thing I know for sure is that they have drove a many good men to drinking... Good luck.