I am now convinced that a dirty fuel tank is responsible for a huge number of lift pump and VP44 injection pump failures.

I have been fighting random/fluctuating fuel pressure issues for about a month now, and eliminating possible culprits one by one.

I first noticed a major FP loss about a month ago, down to 2-4 psi, and immediately changed out the stock Carter. I have the Vulcan Big Line/Relocating kit so my pump is down under the drivers seat on the frame rail. It has performed flawlessly for 5+ years now with an Edge Juice/Attitude. I also have a 1/2" ball-valve behind the lift pump due to the thought that someday I would need to change it out due to failure, as it is the concensus opinion in this forum.
So anyways, I had a replacement pump on hand that I purchased back then (for $65 !!), so I pulled over and changed out the fuel lift pump.
So for about 2 minutes I had good pressure again, just long enough to sing a victory song, when the pressure suddenly dropped way down again.

So I then did a bunch of testing, different gauge, electrical connectors, battery grounding, voltage testing, liquid fuel tank cleaner, blah blah blah, and nothing was wrong. Finally out of desperation, I blew some compressed air back into the tank and my fuel pressure returned to normal. After a week or two I started to lose pressure again slowly but surely. It got to where it was always in the 6-9 psi range (instead of the 14-16 normal).
So, I again blew some compressed air back through the line this morning, and this time I let it "boil" for about 20-30 seconds, and repeated this 3 times. I re-connected the fuel line to the lift pump and pressure has returned to the 14-16 psi range solidly. I now have about 5 trips around town with no problems. I plan on pulling/dropping the tank as soon as I burn enough fuel off to make the tank weight manageable, in order to inspect and clean the tank, module/screen, and feed lines to the lift pump. I am sure I will find something.

Anyways, the point of this thread is that I now have to believe that there are a great number of trucks that have suffered some form of a fuel tank blockage that starved their lift feed/injection pumps into failure. Especially trucks that don't have a pressure gauge. I would also guess that a large number of lift pumps were falsely diagnosed and blamed for failing and causing a VP44 failure. (but that probably is a direct result of a large number of actual lift pump failures)

SO, my final analysis is that the single most important "mod" is the installation of a fuel pressure gauge. At least knowing that fuel pressure has been compromised allows one to begin the process of finding the cause. And the trusty (?) old Carter might not be the culprit.

 

Well I had two new not so trusty carter fuel pumps dead out of the box then switched to a Holley, which ran for 5 years still i upgraded to an air dog. Simple, if you have a vp44 you NEED a fuel pressure gauge, even a stock truck. And buy your diesel from a station that sells allot of diesel fuel.

 

we disected a couple of carter pumps both were electrical around the brush area just poor design pumps. the vp44 is a tempermental piece of junk, to much pressor on it causes all kinds of other problems. you need to keep it between 12 and 16 psi. the extra current draw from some of the larger pumps causes electrical problems. we use a relay on all of our aftermarket pumps for this reason

 

On my 2000, when the stock lift pump failed, one of the first things I noticed was that the old pump was 1/2 full of water ! When you think about it, that is the first "water separator" in the system. Bought a new pump from the local Cummins dealer, installed a NAPA water/fuel separator (with a drain on the bottom of the filter) between the lift pump and the tank, and never had another problem with it. I am convinced that water is what kills a high percentage of the stock Carter lift pumps. I sold that truck with 145k (original VP) on the clock, and the new owner has around 200k on it with only a new starter. Why did I sell that truck?!

 

Install a spin-on pre LP filter. It's pretty easy and helps eliminate any junk getting to any LP and/or VP.

 

Sluggo, you'll be surprised at what you're going to find.

Since 1993 I've purchased 3 New Holland Skidsteers. All have used a small electric in-line lift pump. All had 2 filters, the main filter with a water drain between the lift pump and the injection pump and an inline filter before the lift pump. In all those years I've only had to replace one lift pump. Whenever the pre-filter starts to plug I'll start losing a little rpm first and the power will drop off. Pop in a new pre-filter and all is good not to mention I'll change 2-3 pre-filters for every main filter. Since they use the old Moper gaser style in-line filter they're cheap too!

Since you're using a remote filter anyway, follow the advice mentioned earlier and install a good pre-filter. I think you will be very pleased!

 

i have taken apart many 2nd gen fuel canisters and they are ALL NASTY plugged up with crap. crap so crusty on the bottom it took carb cleaner and air gun to get it out.

 

My 2001 had 240,000 kms on it with no VP44 failures. Good fuel pressure and clean fuel, simple as that. 14-17 psi FASS pressure and good filters. Carter lift pumps are trash.......

 

Another culprit is the tank vent which can be plugged.

Other problems are the connections at the canister for the supply, split dip tube in the tank pulling air, loose couplings at the fuel pump,tank and filter housing.
All of those can create fuel pressure spikes and drops.

 

360,000 kms as of this morning. Yes, it's had a couple of Carters on it and still does and always will. I do have the Vulcan big line kit and the pump is under the drivers seat on the frame rail. Have run Milligan Biotech fuel additive since almost day one ( I beleive Scotty does also). OEM VP was changed out at 20,000 miles with a cracked case.

The tank has been out twice for defective fuel level senders, both times, inside of tank is spotless for dirt and mung.

ONLY get my fuel from high volume truck stop card locks, never from an average joe gas station.

I run my tank down to almost nothing before I fill up. 127 litres is the capacity and I usually fill with about 110 to 115 liters....I have a pretty dedicated route I travel with little deviation so I do push it. But I go by how far I can go on a tank and not by MPG's.

Sure the Carters and the VP for that matter are "fuel cooled" but I have over the years run temp guages on my return lines just to see the temps and they usually run about 100 to 120 degrees on the way back to the tank. But because of the low levels I do get down to, I lose the heat sink effect in the tank.

I would have to check my records but I believe I'm knocking on a 100,000 miles on this latest Carter and do feel that the bio tech is what is doing it.

It's an extra "cost" on each fill up but I'm convinced it is making a difference both in my mileage and my pump life...both the Carter and VP.

The Carter pumps do have a bit of a bad rep but at the same time as everything else, we only hear about the bad ones compared to the who knows how many out there in the world on just about everything over and above a Cummins Dodge.

Jeff

 

What exactly is a fuel "canister" if I don't sound too ignorant? Is that the fuel tank, or prehaps the filter housing?

Sorry for the dumb question...

Doug

 

The filter canister mounted to the engine on the driverside. When taken apart look to the inside bottom for dirt, crud, etc. There should be none.

 

Thinking about this a little more, I had a friend once with allot of fuel contamination issues. As it turned out the clamps on the filler tube were loose. After a thorough cleaning of the tank and tightening the clamps the problems did not reoccur.

 

fuel canister inside the tank that is also the part the sending unit attaches to for your fuel gauge. the bottoms of them are craptastic nasty on the ones I have removed when doing big line kits.

 

gotcha..
I was wondering...
I'm a little apprehensive about dropping the tank for some reason, mostly because I have no idea what I'll need to unhook, unclip, hidden tricks and so on. I also have no idea if I'll need any gaskets or anything. There really isn't much info in here about what to expect when dropping the tank. I have heard that it will be easy, and on the other hand I hear that there are some tricky things to unclip in order to get it down.

I have my fuel level down to 1/8th of a tank, I'm hoping that I will be able to handle that.

Is the tank made out of plastic?
Do I need a floor jack?
Should I spray down with rust-buster penetrating fluid overnight first?
Do I remove the filler hose at the tank or up at the nozzel end?
Should I try to get the tank completely empty first somehow?

Or, should I just go for it?
hehe...

thanks guys