sorry for the long post......a couple days ago when i started my truck it was popping and cutting out and acting like it was gonna die, so i shut it off, waited a minute and started it up again, and all was normal. drove it all that day, night, on, off, etc, no problems...then today im driving down the road, all of a sudden fuel pressure goes to 0, and it starts doing the same thing, pouring out white smoke, so i barley made it to a parking lot and called for a trailer. while waiting i started it a few more times and it did the same thing, then on the 4th start..normal fuel pressure, and ran normal, so i drove home. checked codes, only code was the speed sensor one. i thought forsure it was the vp44, but no code. so then i think ill put a new filter in, i drive it sum more, on. off, all is normal, get a new filter, put it in, start it up, 0psi, but it runs just fine...so i thought i had a isolator problem, hook the manual guage to it, and it goes to 1psi. so now i have it apart to see if i can get my lift pump replaced, thats what it seems like it has to be..but my question is, why earlier its spuddering and smoking white at 0psi, and now it runs fine, but only 1psi on the test port, and it still has no vp44 code???? im stumped.....

 

Read the material on Blue Chip Diesel's website for a pretty decent explanation of what is likely happening.

When the VP44 goes south it does not always post a code, but the lift pump is easy to check to rule it out.

 

Sputtering can be caused by no fuel pressure. No codes because the VP hasn't failed.

These are just guesses based on what you describe. If you only have 1 psi of pressure, the pump is shot.

Even if the VP is bad, you'll have to deal with the lift pump.

Dave

 

well i figured it out....my truck had the dumb intank conversion...that pump was bad, and not letting my other one work...dodge quoted me 400 sum dollars to replace it...so i took it out, bought an airtex, and mounted it back on the motor...truck runs great..however, now along with the bd pump, im at 30psi at idle...should i sum sort of fuel pressure regulator?? what is the safe amount to run at idle?

 

You'll get varied opinions on this. But my VP is still running strong with no less than 37psi EVER. 60K miles 2+ years.

Dave

 

The blue chip site documents reduced efficiency of VP44 with excessive head pressure. I am not sure what pressure will cause damage; I keep mine at 15 at idle, 10-12 under load.

 

Yes opinions do vary.

I used the BD Aux pump mounted on the rail in series with the other (replacement) lift pump mounted near the engine at stock location. Replaced and added when my VP44 did die as a precautionary measure.

28 psi at the pump inlet. No failure. BD has a web site with a forum you can read about more there.