Left home this morning everything was going good. About 6 miles into my trip my truck stumbled real bad but recovered and this was while acellerating right around 1800 rpm. I kept on my journy and it progressivly got worse. Smoke egts, boost, fuel pressure were all normal. Once I arrived at my buddys house it would do it at idle, it never stalls. I chect the FSS wire it was a little loose so I crimped it down and cleaned it up but same results running. I've got a clear hose running to the fuel pressure gauge and I never saw any bubbles in there. I think its the FSS but I'm looking for more ideas. And sorry if the spelling is FUBAR I'm on my HTC. Thanks in Advance.

 

Check for fuel in the fuel. Maybe the lp is bad and pumping air into the fuel.

 

Are you leaking any fuel around the IP?

 

Maybe some bad wiring to the fss. Try hot wiring it. It sounds electrical or air in the fuel. Does it still shut down with the key like normal? Does it act differently hot or cold?

 

I hope he has fuel in the fuel.

Water in the fuel would be bad though........

 

NOPE, LEAK FREE BESIDES THE STEERING GEAR.

 

SHUTS DOWN JUST FINE, HOT OR COLD IT DOES IT. I WAS PLANNING ON A HOT WIRE. Í'M REALLY HOPING THAT IT'S JUST AN IGNITION SWITCH.

 

oil in the fuel is what I meant. You guys know what I meant!!!!! Thats what I get for posting from my phone it is a pain.

 

Even so, with oil in the fuel, it'd still run. Oil will burn with the fuel and if there's enough it'll be a blue-ish color smoke. Is it even possible to get oil in the fuel other than dumping a quart of ATF or 2-cycle oil in the tank when fueling?

I'd assume air in the system somewhere. Bleed the lines wherever you can for starters if you haven't already.

 

I still said it backwards fuel in the oil. Its been one of those days.

 

We've all had them. I assumed that's what you meant though but didn't correct you.

 

I'd throw a fuel filter at it.

 

fleet gaurd 1000 less than a month old and only 4 psi drop across. I'm finaly on my way to the truck, I'll have more info in the next couple of hours.

 

Ok made it home. If I keep the tach above 2k then it's fine. It will "catipiller" when it acts up at Idle but still hasn't stalled on me...yet it get real close this thing sound kinda cool at 4OO rpms...lol
I applied another 12 volts to the FSS and it still did the same thing. I then left that leg on and took away the igniton feed with the same results. No fuel in the oil and the fuel pressure never drops on either side of the fuel filter. I have yet to find a peice of .5 clear hose to see if I'm getting air in the fuel....but my redneck thinking has me believing that if I had enough air to make this truck run like this then I'd see a drop in fuel pressure.. But I will get a peice of clear hose to check it out. The only other thing is that I may have pressure and not any volume, like the in tank filter/screen has plugged up...but that was all cleaned out about 5-8 thousand miles ago when I droped the tank to upgrade to the .5 supply hoses.
Is there anything inside of the High Pressure pump that can cause what the problems I'm having. I have a spare pump that I can throw on but I'm not realy wanting to do that in 110* heat if I'm not sure it will fix it. OH and the cold water over the High Pressure pump does nothing, and there is no rime or reason to the timing of when the "stumble" occures. It will be just fine for 1 minute of Idle time then it will drop out and go for 30 seconds then It may take 3 minutes to do it, so Its not rhythmic as to when it occurs. Sorry for the novel just trying to give info for the brains to come up with ideas...cause mine is not working

 

Water in fuel maybe? Every time it idles weird maybe that's water getting pushed through it? I live here in AZ too and I never ever get water in my fuel but its possible. FSS seems like its not the the problem. If it was trying to close while driving it would have shredded by now. When it does this does it get really rough or does the idle just drop super low. 400 will feel rough of coarse but do you think all 6 injectors are still firing? If so it could be a governor issue thats allowing it to drop rpm way too low. Sounds odd, but I had a similar issue with my 14mm pump. Idled so low it died and would not start even though they are at full fuel when they first crank over. It had no hint of fire. Couple minutes later it fired right up but idled at 1100 rpm when it was set to 800ish.