Engine/Transmission (1998.5 - 2002) VP-44 rebuild gamble... (long!)

[Gary - K7GLD]

Since I recently had to replace my VP-44 due to too frequent P0216 failure codes - and since I had also taken GREAT care to always use lubricity fuel additives since the truck was new - I decided to take a gamble and have ONLY the defective parts replaced.



A bit of a gamble, since it could easily turn out that a partial rebuild MIGHT end up costing close to the same as a full rebuild - but since I'm curious, I was interested in seeing if possible, what exactly had failed in my pump, and to see if my fuel additives had helped at all.



I sent a request that all replaced parts be returned to me for inspection along with the fixed pump - here's what came back:



-



Essentially, all the internal rotating parts - plungers, rotating assembly and bearings were reused - as well as the PSG computer module - more on that later.



And of course, the outer case was replaced to upgrade the brass advance cylinder that has been a known premature wear/failure item.



Here's a shot down inside the VP case - some slight polishing where there was contact with internal components - but NO discernable wear anywhere.



-



Here below seems to be the most likely failure point - shown is the bore and pressed in brass sleeve for the VP-44 timing advance piston - at first inspection, it too seemed unworn - but carefully testing the bottom portion of the bore revealed a small wear area/ridge that *possibly* could cause erratic piston movement, and erratic fuel injection timing - and resulting error code. In any event, it's good to be rid of a known failure point!



I don't know that for a fact, and no supporting info was included with the pump and replaced parts, so I hafta make one of those hated WAG's (wild-Arsed Guesses! )



Newer cases now have a hardened steel liner instead of brass as this one does.



The rest of the advance bore, and the piston itself appeared flawless.



-



Here's the top of the VP case, with the PSG module removed - the larger hollow to the left is the fuel reservoir where cooler incoming fuel contacts the PSG module to provide cooling. The smaller opening to the right is where incoming fuel flows to after leaving the PSG cooling chamber - at that point, the fuel is in direct contact with the pump's rotating assembly in the cavity below.



-



And finally, here is my biggest puzzle - the PSG on my pump was NOT replaced, I was told by their tech that it checked out fine, and was the latest available revision level, later even than the "Fedex" unit:



-



And what's puzzling about THAT, is that as far as *I* know, the most "recent revision level" was not even available until earlier THIS year - and my truck is a 2002!



The tech said there have been *3* PSG's - the original, the later so-called "Fedex" module - and finally, the one II and other Bosch rebuilders only recently started replacing the previous units with...



So what gives?



How could I possibly have the latest PSG module in my original '02 VP-44, if it wasn't even being manufactured/installed until earlier THIS year?



Someone's confused - is it just me?



SOOOoo - anyway, was my "test/experiment" a success?



I'm not real sure - I paid $950 for what was done instead of $1100 the full rebuilt/exchange would have been - but am still left with virtually ALL my old rotating/pumping assembly, as well as my original PSG. Was it worth the $150 savings? Well, If I knew then what I know now, I'd undoubtedly go ahead and pay the difference, and presumably get ALL new parts!



I had hoped that in addition to SOME savings, I'd also get a clear indication as to EXACTLY what was giving me error codes - but in fact, other than the advance bore wear noted earlier, there is NOTHING, no clear evidence or explanation as to what was actually wrong with my pump - and after all, that WAS one of my primary reasons for choosing to make the replacement as I did.



NONE of this post, or my comments should be considered as a complaint directed towards II- they are NOT! I took a gamble, calculated risk that I might learn a bit more about these pumps, and the effectiveness of my use of fuel additives - I guess they must have had SOME benefit, since II saw no need to replace the major moving parts of my pump - so I will continue with Power Service and 2-stroke oil...



MEANWHILE, if any Bosch guys reading this want to shed any light on the PSG issue - or any of the rest, your comments are welcome and invited.

 

[wtfd6]

thanks for the info Gary. its always nice to learn more about the parts we have on our trucks. I have my old core pump that I was actually thinking about dismantling just to learn how they work.


Mark

 

[Gary - K7GLD]

thanks for the info Gary. its always nice to learn more about the parts we have on our trucks. I have my old core pump that I was actually thinking about dismantling just to learn how they work.





Mark

YUP Mark - that's why I like to post this stuff - it seems hard as pulling teeth to get any accurate and detailed info on these VP-44's - so the more info we can provide and share, the better!

 

[BradyWilliams]

We like giving our customers back their old parts. They then can see what the parts they bought looks like and why they were replaced. The pump housing as you can see has a brass advance bore. We never reuse these because they will not pass on the test stand and will cause a warranty for sure. The advance piston is scratched and gaulded. The advance bore will be worn in a similar manner. The shoes and rollers are replaced as they are worn more than can be expected to give long service. And on a repair and return we would do what is needed but we always follow our customers request as to saving money etc. Our exchange pumps are a very good value and represent the highest quality that can be found. Thanks

 

[Gary - K7GLD]

Thanks Brett - but as a matter of curiosity, would what at least appears to be a relatively small degree of advance bore wear cause the pump to set the P0216 code? That is virtually the ONLY visual indication of problem *I* can see - could it be enough?



And what comment can you make on the PSG replacement I covered in my lead post - WERE the latest PSG's you guys are now installing in rebuilds, already being used in the OEM pumps back in '02 - or was I given bad info?

 

[BradyWilliams]

Yes the scratching would make the pump not pass on the test bench. Those housings were taken out of production not too long after they were released. Your PSG was probably a 4 lam PSG or we would have advised to replace it. The latest PSG is called a 4 lam. The Fedex PSG was also a 4 lam. The old PSG was a 3 lam. The new PSG's that we don't have yet which is newer than the newest available now will have a IAT sensor with it. We have not seen these yet but are very excited to start receiving them. Iat sensors only have a 2-3% failure rate which is what we have seen and also what Bosch has seen. We would like to replace those with every PSG that we replace if the price is not much more, Hopefully. I know 2-3% is not much but we always want to make the very best products for all of you. Thanks

 

[rweis]

Interesting post Gary. I especially like the pics.



I liken the VP44 to an aircraft jet engine. It gets rebuilt every xxx engine hours regardles if it is showing wear or not because statistically it is most economical to do it at that time. I think the VP44's are going to wind up being the same maintenance item. Rebuild them every xxxxx miles like it or not before failure. Now what is the xxxxx miles? I flew B-52's and some of the engine frames had been rebuilt multiple dozens of times. I think the VP44 is going to be the same concept.



Remember the older threads about no VP44 bodies being available? Well it seems that they check the frame and refurbish it (steel sleve in the advance piston vs brass) just like a jet engine. They kept your PSG because it tested correctly. I think the 0216 can be caused by the advance piston inaccurately advancing causing "timing errors" eventhough the PSG is calculating correctly. This is where my "cooling efforts" are to the entire VP44 frame system, internal system as a unit and not just the PSG (fins on the PSG, the electronic cooling effort of the PSG etc) area.



I really admire your tenacity on the VP44 issue. You took a gamble and we all learned more, THANKS!



If some of the rebuilders would help in the how many xxxxx miles (or just when it starts throwing 0216 codes) between replacements (Mean Time Between Failure (MTBF)) it might shed some more light on this.



Cost wise I can see II's position in that they have established a set procedure of rebuild that they deliver a reliable rebuilt product with the fewest manhours so they can offer a good price. Everytime they have to deviate from the established procedure it probably cost them more manhours to deliver the same product.



GREAT thread, BTW I am about to finish the "cooling thread" as soon as I finish a couple more test and muse some about a recommendation that the general TDR population can feel good about and implement successfully and at a reasonable cost.



Bob Weis

 

[BradyWilliams]

To further answer your question about the scrated advance bore and piston, injection pumps don't work very well with scratching on key components. Those scratches or gaulding marks may not effect other parts in other places in engines or brakes etc. In injection pumps those kind of wear patterns will not cut muster unless you are just junking pumps together and denying any warranty. We used some of those brass housings long ago before Bosch told us not to use them any longer. They all failed and thank heaven not many got out. Thanks

 

[NoSeeUm]

Thanks Gary!



Jim

 

[rweis]

The BOSCH book on the injection pumps talks repeatedly about the extremely small tolerances in the VP44, and how critically important it is to have absolutely perfectly clean fuel. Mechanical scratching or galling is done for other reasons that we can not control. We can only control what we can as users.



The attempt by Bosch of using brass on the advance piston might have been a good idea on the drawing board, but not so good in practice.



I am just very thankful that there are folks like Brett & II that can rebuild these and we are not relying on DC. What a mess that would be.



Eventually the VP44's will have enough field "testing" and itterations of rebuild so we have a pretty reliable pump. I am getting the feeling we are closer to that end that we were in '02 just because of the upgrades to the rebuild process.



Question for Brett - Bosch must not change the "lam" versions very often if we are only on #4 (what does "lam" mean anyway or its acronym?).



I really like Bretts input (as he has time, notice his reply was after midnight (lol)) and he is one of the very few rebuilders that takes the time to reply and help us figuer out the VP44. His participation on the threads will certainly will be a major input as to where I get my VP44 rebuilt when I have my VP44 MTBF exceeded (0216).



Bob Weis

 

[NoSeeUm]

I would think it is the number of "Laminations" of the back board?



Jim

 

[Gary - K7GLD]

To further answer your question about the scrated advance bore and piston, injection pumps don't work very well with scratching on key components. Those scratches or gaulding marks may not effect other parts in other places in engines or brakes etc. In injection pumps those kind of wear patterns will not cut muster unless you are just junking pumps together and denying any warranty. We used some of those brass housings long ago before Bosch told us not to use them any longer. They all failed and thank heaven not many got out. Thanks

Thanks again Brett - the more info we get on these pumps, the better.



I understand II's policy of automatically tossing all VP cases that have the brass cylinders - but want to nail down, as nearly as possible, that in MY case, that WAS the likely cause of failure and 216 codes, and not simply the result of a routine procedure regardless of the actual functional condition of that cylinder.



Sorry to appear so tenacious on this, but once this issue is settled in my mind, the other issues of interest fall into place far easier - I hate mysteries!



I think what you have indicated up above is a "YES" to that question, let me know if I am wrong, since the primary purpose of this drill was to as nearly as possible isolate the EXACT cause of failure, rather than a "best guess".



At the time that VP-44 was swapped out, I could pretty reliably trigger the 216 code when the engine was reved up to 3000 RPM or so and held there for a few seconds - that was the most repeatable symptom - other than that, the 216 codes were pretty random in normal driving.



I guess my real question is, would typical advance cylinder wear deliver the the 216 error code under the conditions I was able to set them repeatedly?



Added to that, was a phone call I received from one of the II techs upon receiving that VP-44, at which time he asked what failure symptoms I had been experiencing - I told him, and he stated that the initial bench test had revealed NO signs of error codes - but that he would begin digging into the pump to see what he could find.



Anyway, I'll assume the worn brass advance cylinder WAS the cause unless I get info to the contrary - and thanks again for sticking with me Brett - glad you are here for these questions.



Bob (rweis) sez:

Interesting post Gary. I especially like the pics.

The bare case is VERY helpful in better understanding fuel circulation thru the VP-44 mechanism - for instance, the fuel passage from the first reservoir and on into the VP is only 1/4 inch in diameter - I've long stated that in spite of larger lines and fittings, the VP-44 *itself* is the final immovable restriction. What good is a half inch fuel line and matching fittings, if the final opening it all connects to is only 1/4 inch in diameter?

I really admire your tenacity on the VP44 issue. You took a gamble and we all learned more, THANKS!

It's all a slooooow learning process Bob - sorta like sorting out small pieces of a large puzzle - and only getting one new piece every few months! :-laf



There's so much fear and loathing surrounding these pumps, it's a big plus to guys like us if we can uncover new and helpful info - the fact that later VP-44's used failure-prone brass advance cylinders was new to me up until a short while back.



I suspect the selection of brass in that location was done by Bosch due to the natural slipperiness of brass in many situations, and perhaps was their approach to offsetting the reduced lubricity of our ULSD fuels. unfortunately, the advance cylinder was NOT a good place for that hoped for "improvement"!

Cost wise I can see II's position in that they have established a set procedure of rebuild that they deliver a reliable rebuilt product with the fewest manhours so they can offer a good price. Everytime they have to deviate from the established procedure it probably cost them more manhours to deliver the same product.

ABSOLUTELY - and I fully appreciate the standard of quality and customer service II continually provides - plus, I fully understand the difficulty in a line technician's ability to fully document and inform each and every customer exactly what he did, and why - that's where Brett's presence here becomes so helpful.

GREAT thread, BTW I am about to finish the "cooling thread" as soon as I finish a couple more test and muse some about a recommendation that the general TDR population can feel good about and implement successfully and at a reasonable cost.

I'm continuing on the VP-44 cooling bit as well - just yesterday I installed the Pulse-width Modulator to control cooling blower speed - will adjust the speed and continue to monitor temps to See how low the blower speed can be reduced and still obtain effective cooling - will post results as they surface!

 

[MVieira]

Thanks Gary for the post and pictures. This cleared up some of the things I didn't fully understand when I just had my VP44 at Diamond Diesel. It is hard to quiz someone when customers are at the counter and the phones are ringing. Also thanks to Brett at II for his input.



Mike

 

[NoSeeUm]

The bare case is VERY helpful in better understanding fuel circulation thru the VP-44 mechanism - for instance, the fuel passage from the first reservoir and on into the VP is only 1/4 inch in diameter - I've long stated that in spite of larger lines and fittings, the VP-44 *itself* is the final immovable restriction. What good is a half inch fuel line and matching fittings, if the final opening it all connects to is only 1/4 inch in diameter?

It is the combonation and sum of all the restrictive points from the LP to the VP. I believe 1/2 is overkill, but the price is the same so why not.



Edit: In further analysing, typically fuel pressure is measured at the overflow valve which has an effect but a smaller direct effect as long as there is an ample delivery pressure at the VP inlet port.



Jim

 

[Gary - K7GLD]

It is the combonation and sum of all the restrictive points from the LP to the VP. I believe 1/2 is overkill, but the price is the same so why not.



Edit: In further analysing, typically fuel pressure is measured at the overflow valve which has an effect but a smaller direct effect as long as there is an ample delivery pressure at the VP inlet port.



Jim

Actually *I* have NEVER seen fuel system PSI measured at the overflow valve, but rather, at the fuel INLET port...



The overflow valve is on the OUTLET of the VP-44, and is the fuel return line to the fuel tank - the internal feed to that port is a tiny 1/8 inch diameter, and would render any PSI readings taken at that port pretty meaningless as far as larger lines and fittings are concerned.



In fact, since that 1/8 inch discharge flow would be measured for PSI AFTER the overflow valve - and the line on back to the fuel tank is about 4 times larger in diameter and relatively unrestricted to flow, I'd be surprised to see much of ANY PSI at that point, regardless of fuel line size and fittings installed to the INPUT side of the pump...



I take my own PSI readings at the VP-44 INLET port...

#ad

 

[Gary - K7GLD]

The more I ponder the fuel advance wear as the primary cause of my error codes, the more likely it appears. I only started getting those codes after using my new Smarty programmer - and started getting more timing and fuel delivery than the Comp alone had been providing - another TDR member and Smarty user was having very similar issues at the same time I was.



We both quickly discovered that removing the Smarty software pretty much eliminated the P0216 codes, tho' not totally.



Not a direct Smarty issue I'm sure - but rather the likelihood that the added demand for more fuel and pump timing took the worn/weakened advance function beyond it's capability.



In any event, the new replacement pump installed at that time is functioning perfectly so far - and with the Smarty programs installed.

 

[BillBrown]

This has been an informing thread. I am A smarty user with an older pump and having A little diferent but could be very related problem. I do not tow and do not push My truck to the limits like many of the others here but I do like show off for the "think they are hot" little rice burners from time to time. But any way I am getting A lot of backfiring in the exhaust, up around the turbo, higher egts, and more than normal smoke intermitantly. One diesel Mechanic told Me that it had to be A timming problem. I have not set any codes but the timming problem could easily explain My problems and My drop in mileage. Does this sound like it could be A pump ready to go but just costing Me mileage and preformance for now?

 

[rweis]

Oo. I can shed some light on the return line.



I removed the OEM return line right after the VP return and the injector return come together at the T on the back of the block. I put 3/8 fuel line down to coolers on the frame as the fuel is returning back to the tank.



There is 0 psi unless the rpm's are pretty close to cruise speed (2k). At idle it is barely a trickle. At 2k it is a pretty good stream but not much if any pressure. In Bill K's old post he measured the flow rate and got almost none at idle and about 30 gph at 2k. I agree with that in what I saw on mine. The metal return tube fits snugly inside (ID) of an AN-6 hose. I just hose clamped mine 3 times on the metal tube and it holds very well. The OEM flex line (looks like hard clear nylon) that has the larger rubber outer hose (soft protective use only) over it has an ID dia of about 1/8".



From what I gleaned out of TDR threads you DO NOT want to restrict the flow, just let it do its thing. I seem to recall something about 10 psi being the upper limit of the flow pressure back to the tank.



I DO KNOW with good air flow across the return coolers (30 mph or higher) the input fuel temp to the VP44 stops rising and starts falling to OAT +~ 10*. That I have seen over about 6 months and can verify that. At idle the return flow is small, as the VP44 return is based on rpm's. As rpm's increase the flow increases, and the return fuel flow temperature increases.



Bob Weis

 

[rweis]

BillBrown -



TYPICALLY reduced efficiency in the VP44 (lower mileage, missing etc) is a indication that the VP44 is not performing normally and is beginnign to show signs of having difficulty and impending failure of some sort.



I had one of the early "lam" VP's and when I got above 3k for just a few seconds it would 0216. "Normal" driving it would not show 0216. Stress it and it would show 0216. That was before the Smarty came out.



Like Gary implies, stress the VP44 and IF it is "weak" it will code or demonstrate some other sign of weakness. I agree with that analysis.



"Normal" driving you may be able to go a LONG way before it shows more developing failure like not pumping.



Bob Weis

 

[Gary - K7GLD]

"Normal" driving you may be able to go a LONG way before it shows more developing failure like not pumping.

In my case at least, given that the actual wear seen in my advance cylinder seemed pretty minimal, I suspect I could have gone lots longer on the pump - *IF* I didn't want to use what the Smarty/Comp provided...



But who'd wanna do THAT? :-laf :-laf