Just had a rebuilt VP44 put in my 2001 Dodge 2500. Wouldn't start. The guy that installed it said it was because my FASS was over pressuring the IP and he would prove it. He said remove the FASS fuse while I crank it, then put it right back in when it starts. Started instantly. I have 21 psi on my 150 FASS. Now I either have to put a FASS disconnect switch in the cap for starting. (my wife is gonna hate that!) Or try to cut the return spring down to lower the pressure. The mechanic said this was a problem with all rebuilt VP44, can this be right?

 

Found another "softer" spring for the FASS, fuel pressure now 15 psi, truck starts first crank!

 

Not a problem with all reubilt, but a problem with all Vp44 period. They are only designed to operate within a certain psi range.

More is not always better.

Glad you found a good solution.

 

The problem is still returning intermittenly even at 15 psi FASS fuel pressure. Same thing as before, remove fuse from FASS, starts right up.
Got a work around I'm gonna try tomorrow. Will get 12 V + from the pwr windows circuit (windows stop when you crank).

Question is, I read somewhere that an ECM re-program would solve the problem. Anyone know anything about this?

 

The ECM gives a 50% duty cycle signal on the LP pigtail while cranking.
You can either use a relay and a circuit consisting of a diode, a capacitor and a resistor to drive the relay for your fass or use some source that's deactivated while cranking- but you have your fass running when you have the engine off but ignition on.

HTH

AlpineRAM

 

Thanks AlpineRAM,
My current setup uses the ECM pigtail signal to activate a relay, but I'm just talking about getting the pwr from the window motors circuit instead of the battery. Won't this work?

 

Yes, that will work. In fact, that's a fix that the FASS people will tell you about. You're not the only person to experience that problem.

 

Thanks mrclean, I have read on the FASS site this is due to a damage diaphram. Could this be the case on a new rebuild?

It did work by the way.

 

The only thing I dislike about the window fuse solution is that in case of an accident that stops the engine the fuel pump won't be turned off.

AlpineRAM

 

Got that covered, the OEM wire to the lift pump energizes a relay, the window up/down wire is then through the relay supplying the 12 volts to the FASS.