Engine/Transmission (1998.5 - 2002) Operation Lift Pump Longevity (long)

[Edward]

Neil

Something else you might want to consider when talking about fuel passing through the injection pump for cooling. There is also excess fuel bypassed to the fuel tank from the injectors. There is a tee in the return line at the back of the head. This would cause more fuel to pass through the VP44 than actually was injected into the cylinders improving cooling.



Edward

 

[Ncostello]

Setup finally fails...no solution in sight

From 6-10-2003 until 9-1-04... that was the lift span of my lift pump setup.



It was a failure after all. The pump started going below 8 psi at idle and down to 7 psi. My dakota digital started flashing at the preset 8 psi low point. I was on a 1/4 tank. So I filled up and it didn't help. I tried all the little things like filters and re-plugging the connections... but to no avail.



What happened? Who knows. It was sudden and unexpeted. It was fun however I wouldn't suggest anyone do anything anymore to help improve the stock Carter lift pump. I don't think it can be helped. Its a bad deal from the start. Some win and some don't. The stock location seems a good as any in my opinion and I'm going back to stock afterall.

 

[Sticks]

Sorry to hear that.



If I remember correctly, you had filters before the pump, correct? So the pump has to P U L L fuel through the filter before it can start to push.



I am not criticizing, just noting what might have caused your pump to get weak.



Do me one little favor before you trash your system. Pull your pump, pull the top cover, and gasket off, remover the impeller hub assembly, wipe them all off with a lint free cloth, rinse out the inside of the pump as best you can, reassemble and reinstall. I am curious to see if your pressure comes back. My LP was being intermintent about what pressure it would run. Sometimes 8, others 15. I did the above, and it went right to 15 and stayed there.



It is my belief that some sort of debri is getting lodged in the impeller hub, and keeping the vanes in the closed position. Even with the filter pre pump,. the inside of the pump is nothing but metal rubbing metal. They obviously wear, as seen by the scoring on the impeller assembly, and the metal cap.

 

[Ncostello]

I'll do that sticks just to make sure. From what I understand from Stanadyne... the 30 micron prefilter I use has very little resistance to flow and was designed to be used in a vacuum situation. They recommended it prior to the lift pump. I would guess that having that prefilter in there adds very little in the way of restriction based on its size versus flow being produced by the pump. In fact it may be less restrictive for fuel to flow through it than through 3/8" hose.



I'll be playing with it to exactly determine what happened if possible. It could very well be an electrical problem with the motor. Prior to this failure... I did notice that turning on the A/C caused intermittant LP pressure variations for a few seconds. I'm not sure but I will check the impeller area good.

 

[csutton7]

going on 38 months with my setup--chris

 

[mhenon]

I was wondering????

In an effort to save a little cash... . could we use the OEM filter and all the exisiting electronics... as a 30 micron pre-filter. Then use the Carter LP, along with it's wiring, and finally the Stanadyne 5 micron post filter. The only purchase would be the final filter from Stanadyne... and some plumbing. This way you would have a fuel heater and WIF sensor before the Carter LP... along with filtered fuel of course. Install this whole mess back by the tank somewhere... and it's done. As to the wiring. . you only need to extend what's already there.



Mike

 

[Ncostello]

mhenon... not to try and discourage anyone from doing something better, but I am at the point where I cannot advocate the spending of any money to try and improve on something that uses the stock Carter pump. This is irregardless of whether a prefilter is used or not. I dont see where it helped mine whatsoever.



I spent tons of time and alot of money to try and do the best thing possible for the single relocated pump. In the end it was this pump that failed. I'm now driving around with a pump that wont really do much over 8 psi. Needless to say I keep a close eye on the gauge now until I can decide on what to do. I figure I'll still get by without damage to the VP. But something else has to be done as 8 is definately not normal for my setup.



I think I'm going to go with a Fuel Preporator Air Dog. If that doesn't work then I'll get another truck and be done with it. I've played around long enough and its time to do something and forget about it.

 

[ceastmen]

Lift Pumps

Neil,

I have read all of your posts and am impressed with your reseach and your

drive to fix this problem!!

I work for Ball Aerospace in (The Republic of Boulder Co. ) thats another story.

We build some amazing hardware, I work in the Flight machine shop and

have built a lot of complex flight hardware.

I have wanted to build a better fuel system for our trucks as you have

tried to. But I have learned through my 40+ years of maching when to

hold and when to fold through trial and error.

You have put alot of time and effort into this, and probably enjoyed some of it

along the way.

I guess what this has led up to is my former Holley lift pump gave up the

ghost on trip home from the Western Slope last weekend. My wife and I celebrated our 35th together

not to timely. After changing it out on the side of the road and coming home with more pressure than I've ever experienced before, the replacement pump has started to go by the wayside. Time to fold!

I installed a FASS yesterday, nice system (15 psi. ) only time will tell.

Since I have "F" with it ITIS I'm going to make a small stabilizing bracket

for some more support.

Sincerely Chuck E.

 

[Ncostello]

Thanks for the nice comments. Its true I have put alot of time and effort into trying to understand what happens to diesel fuel along its journey from the pump nozzle until it reaches the combustion chamber. Its not a long journey but it sure seems to be a complicated path. I believe there are alot of variables involved. And some of these variables cause our problems either one at a time or in multiples. The Carter is not able to do its simple job because of its weak design. Thats the conclusion I have made and I really cannot offer no real proof why. I cannot take it apart to try things cause it destroys the pump case. So without being able to do that... they just go in the can.



Today I took the pump apart again to make sure it was clean and looked OK. I flipped the rotor blades around and made sure all connections were clean. I also flipped the rubber gasket over to create a new seal.



12. 5 psi is about all I can get. It does not take prime like it used to. The 12. 5 is soon replaced with 8-9 psi at idle and it bounces all round from there while driving. Its the relief valve inside the pump. I'd bet money. But I can't fix that.



I'm just going to go with the Preporator like I said and throw in the towel. I guess the moral to this story is you actually can't polish a turd no matter how you try. But yes it was fun and I learned more about the fuel delivery system than should be legally allowed.

 

[Edward]

Ncostello



Neil you will like the Air Dog! Preporator is a good proven design, they have been pumping diesel fuel for a long time.



Edward

 

[Sticks]

Neil,



I'm sorry that you have given up on the Carter relocation issue. You have to admit that the relocation is still better than the stock location. I did mine during the winter, and immeadatly saw an increase in PSI across the board. I don't know if it was just the relocation, or the upgrade to 1/2" fuel lines, no banjo bolts, and only one elbow, or a combinaton of both. I kept it simple and left the OEM filter inplace. If anything the benifit of the LP on the frame makes it soooo much easier to change out.



Even if the Carter pump is a piece of crap, I can afford to go through 3 or 4 of them before I will start thinking I should have gone with an after market fuel pump.

 

[rweis]

40k and the bypass regulator (to eliminate the check ball valve problem) for the lp seems to be functioning fine. Still on the first lp, carry a spare though.



11 - 12 psi regardless if it is empty or towing the 13k 5er. Not totally convenced that you can't make the Carter run well, yet.



Neil, a lot of what I have done is due to your work and research. Thanks, saved me a lot of "cut and try" approaches. Truely thanks.



Bob Weis

 

[Ncostello]

Thats exactly what it was about. If all my work only helped one person... then it was worth it. Thats how I am I guess. There are good things to be had for me though. I do have a 99 and a 2001 fuel canister. Plus I've got a ton of banjo fittings, washer gaskets, hose and many various clamps for fuel hose. I like spare parts .



In theory I'd still agree that relocation is a benefit. In reality it didn't do me a lot of good. Just as a side note... along time ago I obtained a lift pump off of another wrecked 99. Its the one that had the wire leads instead of a directly attached plug receptacle (one of the older designs). I never tried it as I had purchased a new one for this relocate job. I removed my pump again today and also took the cover off to compare insides to the "older" one I had extra.



The thing I was looking for was to see if both pumps ball/spring inside were the same. The new pump (the one that I was using and went bad) looked as if the ball had slipped up into the spring thus changing the 15psi pressure relief setting. I could tell the other pumps ball was further down in the cavity and harder to see. So I'm saying my pump failed because of the relief valve spring/ball deal.



I've never tried this other pump I have to see if it works. I have no reason to believe its bad. It looks new inside and out as was working previously. It looks OK mechanically and runs perfectly if hooked up to 12V. So I'm gonna carry it with me (and necessary tools ) to perform a swap if need be. I'm gonna run the current bad one till I get way down in pressure. So far I can manage no lower than 7 and sometimes 12. 5 as a high. Right now there is no rhyme or reason as to what the pressure might be. Its basically all over the place.



I figure if I have positive pressure I'm ok for now. I'll just have to keep a close eye on it. I could just go buy another new one I suppose and it may run for a very long time. But this project was a do or die for me really. One last chance you might say.



Rweis... you may have the one thing I should have used. A bypass regulator to keep the stock spring from over working itself. Maybe thats what kills the OEM pump when you actually try and increase flow by reducing suction head and friction losses. Maybe I inadvertantly caused my pump to run too close to its design pressure all the time thus causing the relief valve to be over worked.

 

[Ncostello]

"Obviously a Major Malfunction..... "



I had to go to Noblesville today which is a 4 hour round trip. It was kinda iffy on the way over with pressures jumping around from 8 to 12 the whole time. Then in the first couple miles on the way home... it dropped off to 6 idle and 3 cruise. Any heavy throttle applied would drop to 0 easy. So I was faced with doing a gas station change over to my "never before tried" used spare pump or just keep going.



I decided to pass on the swap out and just concentrate on driving to keep the pressures above 0. I managed 2-3 psi on the interstate and made it home fine. Thus something went wrong quickly and took the pump out in a big and fast way. I guess my previous problem was all the warning it was going to give me.



Glad I didn't do a roadside swap... cause when I did it in my garage tonight my "spare" wouldn't suck fuel at all. It wouldn't even draw fuel out of a full prefilter 6" away. So at least driving home was the right decision.



So now the diesel Dodge sits and awaits some sort of fix. Whether that be a new Carter or taking the plunge for a Preporator waits to be seen.



I was just thinking of installing a new Carter pump w/o the prefilter and just reinstalling the OEM fuel filter cannister. I'd just put the Stanadynes away for another project someday. I'd prolly keep the Carter in its relocated position sort of by modifying the prefilter bracket and getting it slightly closer. Not that it would really matter.



Just thought I'd report in on the total failure here. Looks like this is the end of the line for this long eventful thread. Operation Lift Pump Longevity was a failure in some sense and a complete success in others. I learned alot. Oh, and... thank goodness for gauges!!!

 

[ceastmen]

Fuel pressure gauges

Neil,

Your right about keeping an eye on your gauges, it's the only way I

would have had a clue my Holley lift pump was failing.

When it went to 0 psi. with the throttle off I found a place to pull off

and replace lift pumps.

I did replace the system with a FASS, I am tired of not knowing whether or not the lift pump was going to make it! We'll see how the FASS holds up.

Chuck

 

[rweis]

Everyone seems to be going for the FASS or Air Dog or another electric pump / filter system.



Why are you not looking at the mechanical pump (R. A. S. P. ) the DTT crowd is distributing?



Is it a cost factor?, familiarity factor?, just seems odd that you are going to go to the electric pump idea again.



I have NO affiliation with DTT (I do have one of their trannies) or anyone else. Just courious.



Bob Weis

 

[Edward]

rweis



My personal reasons were. The RASP had no track record yet (lack of miles). It may be a great pump but to me it isn't proven yet. I remember the long list of failed pumps that were supposed to be the answer to the lift pump problem. The real test of miles on these so-called answers revealed reality. Secondly everyone knows that you can push something with a pump better than you can pull it. The RASP has to pull the fuel all the way from the tank to the front of the engine. This may not be a problem but since it is a new design and we do not have a track record yet the question is open. I still think they need to get a couple of these RASP units to some hot-shotters and let them get some real mileage on them.

On the other hand Preporator has a long and reliable history of pumping diesel fuel. FASS also has a successful history. I can't help but think that track record is the reason for people going with these electric units.



Edward

 

[Ncostello]

If you change filters on a RASP, you need to prime the system. Unless the engine is turning over there is no way to prime. Unless you leave the stock electric pump in place as they suggest. Or use an electric pump only to prime. That would mean a bypass plumbing job or sorts.



Or else you could use a hand primer which is a good option too.



I want to keep it as simple as possible. If I went mechanical... then there will be no electric pump in there... especially the stock setup.



Just my thoughts on the RASP. I've held one... and I'm sure it pumps like crazy. There are just drawbacks for me personally.

 

[dcochran]

I'm sure, Edward, that by the time the RASP has a track record that sets your mind at ease we'll all be levitating around the planet in anti-gravity machines or the like. So far as people going for the "other" systems because of a track record goes it's more likely because there just wasn't any other option. Now there is - it's known as the RASP.

 

[Ncostello]

I had our parts guy at the equipment shop go ahead and pick me up a new lift pump while he was out today. We get our Cummins parts at Scheid and they had one in stock. Its as new as it gets. I guess now they include the pigtail extra length for the 99 and older 24V's. Last time I did this that was extra. Cost was $157. 15. Newest part number... which was revised to include the pigtail... is 3990082. Build date was 7/04.



I plan on returning everything to stock more or less.