Engine/Transmission (1998.5 - 2002) VP44 and lift pump

[jandtjil]

Does the lift pump function in some respect to the VP44?



My VP went out while pulling the the camper trailer last week, before I started getting "dead pedal" I noticed some fuel pressure fluctuations. Stopping for the night I checked codes, P0216, I already new it!

Before turning around and heading home, I installed a new filter and lift pump (thank goodness for having brought tools and spares) and continued to experience similar issues.

When pulling below say 62mph, the fuel pressure was more likely to start dropping off and start "dead pedaling", above 66mph and the "dead pedal" and fuel pressure was less of an issue.

I guess my question is related to finding out if the lift pump voltage is regulated by the ECM, dependent upon your VP44 status?

No I haven't independently checked my fuel pressure at the VP with a 2nd gauge, an erratic isolator could certainly be some of the fuel pressure issues I was seeing.

Am bummed that the VP gave up the fight, but was happy that it held up for another 270 miles to get us back home during the weekend.



JJ

 

[Sticks]

The LP is controlled by the ECM. Either on (engine running) or off.

I've seen dead LPs straight out of the box. Possible you got one.

The other possibility is that your pressure regulator/check valve on the VP is worn out or has some debris in it. It is the banjo bolt on the return side of the VP.

If you do not want to do a complete after market upgrade to your fuel system (FASS, Air Dog, Rasp. . ) at least install the Dodge in tank transfer pump, in addition to the block mounted LP. Should give you 20-25 PSI idle and 17psi WOT.

 

[jandtjil]

Thanks Sticks
I am hoping that it is a isolator issue responsible for the inconsistant LP readings, and not ECM/PCM. Hadn't considered the check valve, that will be replaced with the injection pump I presume...

Current LP is mounted on frame, so the transition to a more robust pump won't be too demanding, I even have 1/2" lines from the tank to the filter, but not all the way on the return (partly stock steel).

I haven't paid a great deal of attention to the in tank pumps, do you have any idea how they are holding up?
JJ

 

[Sticks]

All the ones I installed when working for Central Motive Power never had any problems. Near 3 years on some (regular customers). It seems to be the budget end cure for the LP question.

 

[jandtjil]

Good to know. Did you install your FASS prior to the in tank option?
If so would you go the FASS again, or the in-tank.

Cost is about equall, but both FASS/Air dog have lifetime warranties. I doubt the in tank offers that. More importantly though, I want trouble free!
JJ

 

[Sticks]

In tank pump is $350 +/- (cheaper than the original pumpless sending unit).

My truck went through 2 OEM LPs mounted on the block, then 2 more on the frame, then a set of twin LPs on the frame. I gave it up and went with the FASS. This was all while Daimler Chrysler was still preaching/in denial that there was nothing wrong with the block mounted pumps, and that pressure did not matter.

 

[mhenon]

The OEM LP mounted on the block was the dumbest thing DC ever came up with. Even Carter said to mount the pump below and close to the tank. I imagine DC wanted Cummins to provide the whole package, LP and all, so they wouldn't be responsible for failures. Boy was that smart on their part.

The Carter LP is margional at best but if you move it to the frame and below the tank you have a much better chance of survival. It's then pushing fuel to the VP instead of trying to suck fuel from the tank. I'm still running a frame mounted Carter and going strong at 120K miles. When my two spare LP's are gone I'll probably buy an Airdog or FASS.

Just for the record I haven't had a Carter die on me yet. I've changed a few thinking they went belly up but it always turned out to be something else (gauge, isolator, etc. ).

Mike

 

[jandtjil]

Agreed. Frame mounting is far superior, if for nothing else convenience.
I suspect that the last LP may in fact have been an isolator issue as the new LP began erratic pressure within minutes of being installed. But the pressure reading were higher, much higher with the new LP. This is the 3rd frame mounted OEM type LP for me, and the last.

Sticks, How long have you been running your FASS?
JJ

 

[Sticks]

Sticks, How long have you been running your FASS?

JJ

2005 - summer.



I need to shim out the relief valve. Holds 13 at idle now. Still can't pull it under 10 though. I'd be more comfortable with 17 at idle.

 

[jandtjil]

Sweet! Five years reliable, that's what I,m talkin about.
jj

 

[fstfish66]

i have genos relocation lift pump kit,,i have not gotten back to it but looked once after i replaced the orignal lift pump,,,whats the best way to cut the line?? is it easier to remove the tank to access the hard line??? its completely up against the frame rail at the point where it needs to be mounted,you all know this im sure,,,1/4 tank of fuel,,and how t ocut the line with out making sparks,,,

thanks in advance

 

[JMetzger]

Sticks, I have a HPFP 95 Fass, can that be shimed like you did yours or is your a different model. How do you shim & where did you get shims. Thanks.

 

[kurgan]

Does the lift pump function in some respect to the VP44?



My VP went out while pulling the the camper trailer last week, before I started getting "dead pedal" I noticed some fuel pressure fluctuations. Stopping for the night I checked codes, P0216, I already new it!

Before turning around and heading home, I installed a new filter and lift pump (thank goodness for having brought tools and spares) and continued to experience similar issues.

When pulling below say 62mph, the fuel pressure was more likely to start dropping off and start "dead pedaling", above 66mph and the "dead pedal" and fuel pressure was less of an issue.

I guess my question is related to finding out if the lift pump voltage is regulated by the ECM, dependent upon your VP44 status?

No I haven't independently checked my fuel pressure at the VP with a 2nd gauge, an erratic isolator could certainly be some of the fuel pressure issues I was seeing.

Am bummed that the VP gave up the fight, but was happy that it held up for another 270 miles to get us back home during the weekend.



JJ

I had nearly the exact same thing happen to me last week while pulling my camper. I had been getting dead pedal (with white smoke if I floored it) every day for a couple weeks before i left. Checked codes and had P1693 and P0216. I changed the fuel filter just in case (hoping against hope). My biggest problem was when pulling up foothills in the 65mph range. That thing would just die, and I'd have to shift all the way down to 4th on hills I've never had to downshift on at all. Reading bluechips website, I really think the vp is dead. I still have some work to do on checking, but I have settled with the fact that this may be a good time to start upgrading. Bad vp or not, I will be installing some type of FASS system. Hope you get yours figured out.

 

[Bob Cochran]

When I did mine with the Vulcan(same as Geno's sells) I cut the line as close to the tank as possible. Diesel does not ignite like gasoline and is actually pretty hard to get it to catch fire.

i have genos relocation lift pump kit,,i have not gotten back to it but looked once after i replaced the orignal lift pump,,,whats the best way to cut the line?? is it easier to remove the tank to access the hard line??? its completely up against the frame rail at the point where it needs to be mounted,you all know this im sure,,,1/4 tank of fuel,,and how t ocut the line with out making sparks,,,

thanks in advance

 

[Sticks]

Use a pipe cutter. Clean straight cut, no spark (agreed, really don't have to worry much about ignition from grinding or sawing - possible, but the grim reaper would have been looking for you if it did, and if that failed then something equally unlikely would have happened next, like the fuel tank straps breaking and dropping the full tank on your head)

 

[Bob Cochran]

I will be honest I used a little air cut of wheel. To use a pipe cutter because of it's size requires removal of the line from the tanks forward. I had about 1/8 tank of fuel and jacked front of truck in the air lost very little fuel. At the time was relocating the stock LP so was being LAZY. Later replaced with AirDog so removed it later anyway. What I do to save a buck and wind up spending the bucks anyway and additional labor!!!!

 

[jandtjil]

Kurgan
Sorry to hear your similar troubles. After reading multiple posts by some real smart folks on here, I decided to undertake the FASS/VP-44 install. Weeks later my truck is back running, with fuel pressure that pulses with the VP overflow (I'll get around to fixing that soon). I still spent a fortune, but fixed/upgraded a half dozed other items, rather than the same amount and only getting a new VP and an intake lift pump from the dealer. You mentioned 65MPH and the engine just dieing off, mine was kind of opposite, if I stayed above say 68 the VP timing seemed to stay in sync and it ran acceptable, below that speed and I was coasting!

 

[fstfish66]

thanks for all the replys,, reason i asked is ide like to relocate the lift pump with out removing the tank if possible, and yes the hard line is snugg up against the frame rail,with hardly any free play where the cut would need to be made, just in front of the tank,,,,another fellow gave me a great tip,,,install a ball valve in front and rear of the lift pump,so when replacing the pump,it wont make a mess,,,good idea,,,looks liek ill be removing the tank,, so far this lift pump is the only real problem the truck has had,,,but then the design of the blow by bottle isnt so great either,,,,



thanks for all the replys,,,

 

[Bob Cochran]

What don't need no stinking ball valves!!! A real diesel person used diesel fuel for underarm deodorant. Though I did not install ball valves. I did run tank down to 1/4 jacked up front of truck and put on jack stands and did not lose very much fuel. If your just moving the OEM LP back to frame rail the ball valves good idea as I went through 3 of them 2 relocated on the frame rail before installing the AirDog.

 

[Crazy Horse]

It's been about 4 years since I upgraded my fuel delivery system but it seems to me there was a hose I pinched off with visegrips at the tank to prevent fuel flow when the line was cut. I may be having pipe dreams??? Here's the Photos.