CJSamples

Ok,
When I got in the truck today as I was pulling out of the subdivision I noticed the fuel pressure was ZERO. So I babied her back to the house and just took the wifes car.
Now my question is I can hear the lift pump run when I bump the starter. Can it run and not produce pressure? I did a quick check on it before I really had to leave and it showed nothing. I rechecked it when we got back and it showed about 5 psi and died off pretty rapidly. I have had the gauges on for maybe three weeks and the first night I had the gauges on I had a small leak that killed my pressure indication, so that was my fault. I am pretty sure the gauge is good now as I have put almost 2500 miles on her since the install.
I have been trying to decide if I would do the BD kit, the vulcan big line or a mix of both and now I think I really have to decide quickly. I am guessing my first line of attack would be to verify the gauge reading somehow, my issopro gauge is connected thru the schrader valve then to an isolator. I guess I could pull up the water drain and see if it sprays out like it did the first time I checked it and didn't seat back closed.

Anyone else had this weird indication problem while being able to hear the pump run?

oestreich84

I am going through the same thing right now. Yes the lift pump can be bad and still sound like it is ok. I am replacing mine with 2 Carter P4601hp pumps. Less than $100 each from napa. I am going to mount one in the stock location, and one back by the tank. I am also getting myself the Scotty smart fuel system for Christmas That should be good enough to last the lifetime of the truck.

slim51015

About two years ago, When mine went out it would run but pump no fuel. I took it apart and found the impeller presses on the motor shaft with a plastic bushing. The plastic bushing was bad. The pump motor would spin and not turn the impeller.
Had it replaced under warrenty.

Bart Timothy

I wouldn't be too paranoid about loosing your VP44 because of low fuel pressure. I've seen these truck running at a negative fuel pressure for several thousand miles and the VP44 lived through it. Until the fuel pressure was tested with a guage, the only signs of a dead lift pump were engine misses from fuel starvation on these trucks.

The VP44 has been used over in Europe on Audi's, Vauxhall's, Ford Focus, BMW's, and Nissan's. I don't know about the others, but I believe the Audi doesn't even use a lift pump.

Instead of mounting one in the stock location, mount them both on the frame. It's the vibration, heat, etc. of the stock location which is killing these pumps.

blackdiesel

try out a holley blue. i just installed mine and it pegs my 15 psi guage and i can only bring it down to 14 under full throttle. it cost me right at 100 bucks.

amartinson

I have to strongly disagree with this statement. It has been proven by many people on this site and others that the VP requires a minimum amount of pressure and volume from the lift pump to provide adequate cooling and lubrication to the pump. It is not an instant failure, but many have lost a very expensive injection pump due to the failure of the lift pump.

Everyone that owns one of these trucks should have a fuel pressure gauge IMO.

Bart Timothy

Go ahead and believe what you want. My experience and advice from experts says different. Many people on this site, and others, are only guessing about what causes the failures. It's a case of the blind leading the blind, which is leading to a general paranoia about VP44 failures.

There are a half a dozen reasons the VP44 fails ... lack of lubrication, and heating the electronics are ONLY two of them.

Mopar1973man

Ok Guys...

I look at this way... We are all learning from one and other. But there are many reasons why a VP44 fail. It really doesn't matter what you do... These VP44 pumps are flawed and have problems. I've heard several stories obut pumps dieing for all kind of reasons and for no reason at all. So I look at it this way... Do what you can to protect you VP44 from failing. If you do find a secret to long life pass the word along so we all can learn from you...

No matter what.. I'm still watchful of my VP44 and pressures. It's a weak link in the Cummins heart!

CJSamples

I am thinking of going ahead and doing the big line upgrade. I had found a site where the guy was nice enough to post the part numbers of the fittings needed and such. What I do need to know before I tear into all of this, does the LP have a two wire harness that I can splice to reach a relocated Carter or Holley? I am pretty sure I can find all of the parts locally except for the longer harness that can be purchaed from Vulcan or BD.

I am hoping a quick trip to Napa and the hose shop will get me everything I need and then I just have to extend the harness back to the new pump location. It is going to drop below 30 here for the next 4 days, so I want to be all set when I get started.

Thanks again guys, excellent replies!!

Chris

Bob H

Check your fuel lines. Where the steel line from the tank joins the rubber line to the pump is very prone to leaking, sucking air. Happened to me, two .89 hose clamps 8k ago. Works fine, great pressure. Lots of pumps have been tossed because DC used a cheap slip together fitting. Just a rubber hose slid over a steel line. Check the inside frame rail under drivers seat.
Bob H

Clunk

I'd go with the kit. I spliced mine and it was a pain. You pull the wire and connector down between the starter and block just to get to it. I cut the connector, butt spliced, soldered and double heat shrink insulated the connections to 3 ft. of wire to be sure to have enough wire to get to the pump. The yellow/white stock wire is pos.+ and the black/white wire is negative -. The Carter 4601HP pump electrical post nearest the discharge fitting is pos.+
I drilled and tapped the bracket holes after removing the front driveshaft for working room and used red loctite on the mounting bolts pulled just snug because the frame rail is kinda thin.
If you have too much fuel in the tank, you'll get a diesel bath. If you don't use jackstands and the truck falls on you, your next of kin will have to pay for a cheap funeral.
If you install ball or barrel valves on the lines, the next pump change can be done in about 10 minutes( the record so far is 7 minutes).

Geico266

What are the other reasons? Can they be attributed to fuel lubricity? Vibration? What?

We learn from each other here, sure there can be some voodoo, but my experience has been 80% of the advice here is correct. I have never gotten the impression we know it all.

Would you not agree that keeping the fuel pressure to factory perscribed minimums is a good thing or should we take the LP's out altogeather?

Let us hear what you think. I'm not trying to be sarcastic, I want to know as much as I can to keep my truck (original VP) running another 180K miles.

Bob H

Read the entire TBS on fuel pump problems. No one seems to get by the lack of pressure or flow. The second test is air bubbles in the fuel. I think this is what takes out the pump and the VP. Only My opinion.
Bob H

Clunk

I was shown rusty parts and a burned up fuel valve coil (VP44) when I visited the local rebuilder here. Water in fuel and lack of cooling...now what causes that?

flippinfred

The install instructions that came with my FASS had about a full page on
the VP44. THEY contend the problem (most commonly) is w/the diaphram
separating the low/high pressure sides of the pump. When subjected to less
than 5 psi the diaphram will crack due to flexing beyond its' design parameters and that begins the death spiral.

Don't know if it's true or not but it sounds good.