Engine/Transmission (1998.5 - 2002) VP44 on its way out

[JdmFreak]

Well my VP is on its way out once again... . number 3 now. This one has lasted almost a year (38k). Haven't gotten the dead pedal or code yet, but, it is having more probs with getting its self going when just releasing the clutch. Also breaks up around 2200rpm as it did before... . oh not to mention the great fuel milage.



Question is: is there a way to trick the truck into throwing a code or just straight out killing the pump. I have a Bosch pump and warranty will be up in 20 days... . good timing eh? I don't want to see like a cheap ***** but if i can avoid another 1200 for a stock pump i would be happy. I might even buy the one who tells me the easy way to get this replaced a beer or two



Thanks in advance

 

[nps]

Well my VP is on its way out once again... . number 3 now. This one has lasted almost a year (38k). Haven't gotten the dead pedal or code yet, but, it is having more probs with getting its self going when just releasing the clutch. Also breaks up around 2200rpm as it did before... . oh not to mention the great fuel milage.



Question is: is there a way to trick the truck into throwing a code or just straight out killing the pump. I have a Bosch pump and warranty will be up in 20 days... . good timing eh? I don't want to see like a cheap ***** but if i can avoid another 1200 for a stock pump i would be happy. I might even buy the one who tells me the easy way to get this replaced a beer or two



Thanks in advance

I used to think like you until my warranty expired about a week ago. Now I'm feeling good because I know that I can go to a reliable rebuilder and won't get another problem installed from the dealer. I also don't have to worry about the dealer mechs messing up my truck when my VP44 does go out (if ever).

 

[Mundgyver]

Questions if you please



1. Your input fitting to the VP, is it a Banjo bolt or straight in? If straight in, did you drill it out to allow maximum volumn of flow? By drilling the straight in fitting out to a larger diameter and providing greater volumn of flow, you help the cooling of the VP. 3/8ths I. D. is a good size to be working with.



2. What is your fuel pressure running to the VP? You should be looking for 15 PSI max.



3. Is the pressure relief valve in the VP opening at 14 psi? If not what is it opening at?



4. Are you using a fuel additive about once a month?



5. Do you know at what temp the VP is running? A fuel cooler helps the VP a great deal.



I still have my original VP at 164,000+ turns with no signs of dying yet with particular attention paid to the above questions.

 

[BradyWilliams]

Do you have records that show when you purchased the Bosch pump. If it was a Bosch or Mopar reman pump we could process the warranty for you. We can't get r&r labor but the pump warranty can be sent through Bosch as they are the people that supply the remans for Cummins and Mopar. Thanks 1-800-955-0476

 

[rweis]

Mundgyver #3 -



I can't resolve 2 questions about the VP44 about the the Pressure control valve and the Overflow valve. I know they are different and have different purposes.



The pressure control valve is at the vane supply pump. As I understand it the pressure control valve is there to prevent the pressure from reaching undesirably high levels at high rpms and the pressure control valve is vented back to the intake port. What psi is the pressure control valve set at? The vane pump is raising the low stage feed pressures to 116 - 362 psi (8 - 25 bar) to input to the high pressure radial pump section.



The outflow valve is there to cool the pump and vent any air as it is on the top of the pump and has a small throttle bore designed to do so. The Bosch Diesel Engine Management book on pg 215 states "The entire low-pressure stage of the fuel injection pump is precisely coordinated to allow a defined quantity of fuel to escape through the overflow valve and return to the fuel tank". However since this valve is after the vane pump and internal pressures should be in the 116 - 362 psi (8 - 25 bar) range what is the outflow valve ball valve compression spring set to? I keep reading it is set to 14 psi, how can that be?



I have something wrong somewhere, help me out and figure out where I have gone wrong.



Bob Weis

 

[Mundgyver]

My understanding is that the return line to the tank is set to an opening pressure of 14 psi. This is to keep from doing a "Hydraulic Lock Up" (too much pressure) into the input of the VP. This is the way is was explained to me and the way I understand the VP to work at the fuel supply inlet.



The book that you have, is it something that is redily available for this model VP-44?? If so what is the exact title and puplication reference?? Sounds like it would be very interesting to go through.

 

[rweis]

The book is:

Robert Bosch GmbH "Diesel-Engine Management" 4th edition Systems and Components ISBN 0-8376-1353-1



I got mine from Bentley Publishers 800-423-4595 www.bentleypublishers.com



It covers the history, how a diesel works, new concepts like bio diesel, air filters, fuel droplets, all aspects of fuel injection, patterns, NOx, timing, nozzel designs,low pressure fuel supply, fuel filters, fuel supply pumps, in line injection pumps in detail, design variations, size M pumps, size MW pumps, P pumps, P10 pumps, CW pumps, govenor control systems, (we are up to page 144 of 493 pages), ... . it even gets into particulate filters and the use of urea as a catalyst.



But for our VP44



It shows the return line to the tank valve is in the low pressure feed section of the high pressure rotary pump to bleed off any remaining pressure when the solenoid is opened. But the pressures over there are 8 - 25 bar (116 - 362 psi). I can not imagine it is set at 1 bar (14 psi) when the feed pressures to the high pressure side (where the return valve resides) are 8 - 25 bar, BUT I COULD BE WRONG and hence asking for clarification.



IF the tank return valve is at 14 psi, then why would there be a vane pump to raise the input psi to the high pressure pump feed to 8 - 25 bar? Why not just feed it 20 psi and let it return everything over 14 psi.



Remember the timing device pistons also run off the pressure out of the vane pump, which I am reasonably sure is more than 14 psi, but is the same pressures that the fuel return valve sees.



Anyway, sure could use a little clarification from someone that rebuilds these things.



Bob Weis



The only thing I can figure is the return line is so huge with respect to the valve orifice it drops the 8 - 25 bar rapidly to ??? bar. I read something on the fuel return line that it should not be allowed to go above 10 psi. From the "pumps, lines, what nots" thread the flow rate at high rpms was measured to be about 30 gph, and less at lower rpms.



The pressure control valve over in the vane pump section is there to prevent undesirably high pressures when the vane pump is at high rpms, and has (I think from the diagram) nothing to do with the fuel return valve.

 

[Mundgyver]

Well looks like I will be ordering this book. My impression, the way it was explained to me was that right where the fuel goes in to the VP case from the outside, next to it was the return line for the input chamber and it was, or is supposed to be set at 14 psi. Once the fuel was in this chamber it was then picked up by the intermediate pressurization stage to boost it up in prep to put it into the hi pressure pump.



I will see how fast I can get the book here. Should make for some very enlightening reading on my part.



Thanks for the exact title and such.



-Wally-

 

[Mundgyver]

Well I ordered two books. Got the one you got



Bosch Handbook for Diesel-Engine Management $59. 95 and I also ordered



Distributor-Type Diesel Fuel-Injection Pumps $34. 95 which covers the VP-44 in more detail.



Hopfully they will be here by Monday. Oo. Oo.

 

[Cliffman]

It covers the history, how a diesel works, new concepts like bio diesel

What does it say about Bio-diesel???

 

[rweis]

I added Distributor-Type Diesel Fuel-Injection Pumps to the library today. Will be here in a couple of days normally.



Bio Diesel (pg 48)



Fatty Acid Methyl Ester (FAME)



Commonly known as bio diesel. There are several variants of rape seed oil, soy been oil, sunflower oil, palm oil.



B5 is permitted as a diesel fuel in accordance with EN 590. The european FAME specifications are contained in EN 14214. It is essential to ensure good aging stability and to eliminate contamination caused by the manufacturing process. FAME MUST meet EN14214 regardless wheather it is used directly or as an additive. When adding FAME to diesel fuel it must still meet requirements for pure diesel En590.



The production of FAME is uneconomical in comparison with mineral-oil based diesel fuels.



Pure, unesterified vegetable oils are no longer used in direct-injection diesel engines since they cause considerable problems, mainly due to their high viscosity and extreme nozzel coking.



There are pictures of deposits on actuator mechanism caused by FAME and bearing damage caused by free water (@ 5,600 km)



I am under the inpression that the extremely close tolerances of the VP44 do not make a friendly environment for FAME. Some of the tolerances are all but an exact fit. ( some of the tolerances mentioned later in the book under the radial piston section are 0. 1um)



Bob Weis

 

[Cliffman]

Awsome! Now, can you put that in plan english

 

[JJohnston]

Actually these crappy Bosch pumps work very well if they are re-manned by Blue-Chip Diesel. They up-grade the prob. areas like the alum. piston,and the computer board. I've installed 3 of them now. One on my truck. It handles Veggie fuel very well after its heated to 150*.

I dont mix bio fuels w/ diesel. Straight veggie is the way to go. I have over 20k miles on waste filtered vegetable oil. No probsat all. My injection pump actually likes it better than petrol. When in veggie mode my fuel pressure goes up 3 lbs.

 

[Mundgyver]

What type of metal did they replace the aluminum piston with



Titanium would be nice

 

[ThrottleJockey]

Titanium





Sweet. :-laf