Seems that Fass feeds too much pressure and the VP44 does not like it. The pump is controlled through a relay tied into the stock pump to supply pilot voltage to the relay coil, I guess just that split second that it puts pressure to the pump is enough to screw it up. If I wait, for the pressure to drop, it will start OK. I was thinking of putting a time delay relay on the pump? http://www.primelec.com/Electronic-Components/Relays/AGASTAT-12-Volt-On-Delay-p7886012.html

I think I spent a few months playing with just that very time delay relay I don't see how having pressure would mess up it's starting ability though. Would make it start better if anything, I would think. I wonder if it feeds it so much pressure as to open the overflow and that does something that makes it start worse. Hmmmmm

i've read about this in other forums...most people agree that a diaphram inside the pump is ruptured. this is usually caused by running low fuel pressure to the VP44i believe there is suppose to be a delay, or something when you turn the key...err i'm not wording this right.alot of people get by with a delay. but high pressures(above 20) usually have people getting hard to start situations. if the diafram is ruptured than most i have read crank at 7-8psi then run 15psi

According to Blue Chip, that is indicative of a bad computer on the pump. Today I went on the interstate, and it still seems to be lacking, does not accelerate like it used to at cruising speeds. I was suspect of that computer before I even joined this forum.

http://www.bluechipdiesel.com/vp44diagnostichelp.html "HARD START HOT OR COLD"

I believe Mike has a diagram on how to wire a shut off for the pump. Once it starts you flip it back on. I agree with what guesswho512 said

I believe Mike has a diagram on how to wire a shut off for the pump. Once it starts you flip it back on.

it think he meant this: http://mopar.mopar1973man.com/cummins/2ndgen24v/fuel-pressure/fuel-pressure.htm

it think he meant this: http://mopar.mopar1973man.com/cummins/2ndgen24v/fuel-pressure/fuel-pressure.htm

Yeap if you disconnect the lift pump on a hard start and it start instantly you know the VP44 diaphram is ruptured from low pressure. My band-aid fix is at the bottom of the page...

The truck does not start normal, cold or hot, plus it still will not run like it used to, on the highway, at cruising speed it still has the dead pedal going on as well, and I think it could run better at lower speeds as well. These are pretty much 2 classic symptoms of the computer on top of the VP44 going bad. I think it is time for Blue Chip to send me another VP44, he says he has seen those computers fail very early in the life of a remanufactured VP44.

Well, today it started fine all day, so I guess I wont be needing the time delay, and that should pretty much rule out the warranty voiding diaphragm, but I did contact Blue Chip to get another 16X pump sent out. I will let you all know the outcome in a few days after I get it and make the swap out. At least I know the new VP44 is gonna love that Fass, thanks to all of you at Mopar1973Man.

Keep use posted I'd love to hear the fix to your problem...

Now, I have 2 more symptoms, I decided big blue is going to stay in the shop until I get the new pump installed. I am not paying a heavy truck tow bill. Now, when I started it yesterday it had a rough idle, and today I started and it stalled, restarted it, hard starting and rough idle, so I threw all the tools I needed into the Sprinter, and went to work. Now I got 4 classic symptoms of the VP44 going bad, the only thing left is: truck dies going down the road, no start, high speed high load miss, and doggy at take off. So I got 4 out of 8 of the common symptoms.

how old is that vp44?

3000 miles, and less then a year. Scanned yesterday, and about a weeks ago for DTC's none are present.

Well thats a good sign... But is the hard starting still there?

Yes, intermittent hard starting, so we know it is not the Fass causing that problem at least. Pump is supposed to be here today, I might get it put in by Sunday or Monday?

Damn, they accidentally shipped my 16X to Texas, and I got the 15X that was supposed to go to Texas, I guess there goes my plans to switch the pump on Sunday!!

man the shipping industry is sucking here lately!

It is Blue Chips fault, wrong tag, wrong box.

I just had the same thing happn for a alternator... I order a alternator for a Jeep Wagoneer and the the alternator I got was a Pontiac they phyiscally looked the same but the mounting points were different. So hang in there I'm sure they will get it sorted out for ya...