CR engine HPFP analysis

[eddif]

HPFP Bottom Flush Drain WARNING

Got to love Grace. I kept getting this mental warning light. LOL

Warning:
If and when the bottom of the HPFP is drilled and tapped for drain, flush, testing purposes.....There must be 3 (?) or more things done.

1.. Insure an anti-siphon connection with solenoid valve to prevent a HPFP chamber empty start.
2..Develop a purge / drain process to refill the HPFP after any work with fuel drain and test port to prevent dry starts.
3..Engineering of lines and use must be spot on for the pump to use a bottom drain.
4..If an orifice running purge is done it probably needs a solenoid to prevent port being open when car is not running.

Stock the hole to withdraw fuel leaves the HPFP at least 1/2 full at all times.

While test ports are fine it is equal to at an oil change "you must put the drain-plug back in and refill the sump with oil".

After a HPFP service you must make sure the HPFP is at least 1/2 full of DIESEL.

I do not mind being involved with good ideas, but at times the good ideas have to properly done or disaster can follow.

Let us discuss all this before someone runs out and does a drain without a diesel refill.

We may need a top-off plug at the same time we do a drain plug. This would be like a Manual transmission with fill and drain plugs to insure proper fill level in the transmission.

If you drain a HPFP you must re-fill the HPFP with diesel before start-up.

eddif

 

[eddif]

While we have some information about the room under the left front fender, I still think we should have a photo or two with a filter unit tried for fit. We need to know how many filter units will fit here. If we decide on:
1..a water seperator
2..a seperate HP 2 micron filter
3..an 8 micron (?) return pre filter with a possible finer final filter.
4..etc

Just how much room is under the left fender area?

Also


I think it would do well to have multiple folks testing pressures in the fuel system. Not just anyone, but those who know what is going on. We might discover system failure information. We might discover a lot of different pressures due to ambient air temps too.

eddif

 

[specsalot]

While we have some information about the room under the left front fender, I still think we should have a photo or two with a filter unit tried for fit. We need to know how many filter units will fit here. If we decide on:
1..a water seperator
2..a seperate HP 2 micron filter
3..an 8 micron (?) return pre filter with a possible finer final filter.
4..etc
Just how much room is under the left fender area?
Also
I think it would do well to have multiple folks testing pressures in the fuel system. Not just anyone, but those who know what is going on. We might discover system failure information. We might discover a lot of different pressures due to ambient air temps too.
eddif

I haven't put my Golf up on stands/ramps to get a look under. But there is likely room to locate pre-filtration/water separator closer to the lift pump to keep engine compartment clutter to a minimum. For folks who live where it is cold in winter, filter addition will be a challenge due to potential pour point issues. There is a lot of focus on warm up in the existing fuel system design. Perhaps this is a vulnerability? Maybe this is part of the MY2012 Passat design change.

Fuel pressures at any point in the system may be more variable than folks realize. It really depends on the relief valve setting on the lift pump and surplus capacity as compared to normal fuel flow. The restrictor in the return line at the swirl pot influences overall system pressure values. It will also vary with engine load, warm up status of the preheating valve in the fuel filter, etc.

I haven't thought about monitoring for a while, but there is a decent chance that abnormal shifts in system fuel pressure contribute to failures. If the input pressure to the HPFP were to fall to ~ 63 psig, return flow through the pump would go basically to zero. This sets up for pump overheating and potential lubrication failure due to higher fuel temperatures. Here again this may be part of the basis for the MY2012 Passat redesign.

 

[eddif]

I haven't put my Golf up on stands/ramps to get a look under. But there is likely room to locate pre-filtration/water separator closer to the lift pump to keep engine compartment clutter to a minimum. For folks who live where it is cold in winter, filter addition will be a challenge due to potential pour point issues. There is a lot of focus on warm up in the existing fuel system design. Perhaps this is a vulnerability? Maybe this is part of the MY2012 Passat design change.

Having the water seperator near the lift pump has already been discussed.

Because the engine compartment has components scattered there is little room. The under fender area will not bother under hood engine compartment room. I keep on the task of evaluating the under fender room because of the under hood condition.

We will perhaps (as someone mentioned) have 63 psi to help with fuel flow at low temps. If it needs a heater one might be fitted.

If someone wants to reorganize under hood room, by all means go for it. Things can be moved around to gain room for the filters there. Some people have a knack for new brackets and relocation. This has been discussed for some other reasons. I am not insisting on anything, but encouraging the use of others in all this. I have looked at things for hours and got no ideas, and have someone look for 45 seconds and suggest a good solution.

I am again encouraged by the owner solutions that are suggested. Even if VW does come through in some ways, I doubt they do all the things necessary for a 300,000 mile car(you also mentioned the multi-direction approach yourself).

eddif

 

[specsalot]

VW is mainly in DC on the fuel pump issue. I think Bosch has a gun to their head. I find it too hard to believe this was ever Bosch's problem, except for agreeing to build it per VWs design direction.

 

[N2UADTDI]

Is there such a thing as a sensor that could determine if there is gas in the diesel?

 

[manual_tranny]

Is there such a thing as a sensor that could determine if there is gas in the diesel?

Yes, the "open flame sensor". LOL! Sorry, just kidding!

I tried google searches of "gasoline sensor", "ethanol sensor", "gasoline detector", and "ethanol detector" and came up with interesting results. Maybe looking for ethanol is a better approach, because some additives that provide lubricity also contain chemicals nearly identical to gasoline.

 

[Jack Frost]

One could design a sensor. It might be a piece of styrofoam immersed in the fuel tank that keeps two metallic contacts seperated. When the styrofoam melts (because of gasoline) the contacts are released closing an electrcal circuit. The car's electronics would notice that the voltage has dropped across the contacts and would then shut off the fuel pump saving the day!

 

[specsalot]

Is there such a thing as a sensor that could determine if there is gas in the diesel?

Not likely

Yes, the "open flame sensor". LOL! Sorry, just kidding!

Too Funny

One could design a sensor. It might be a piece of styrofoam immersed in the fuel tank that keeps two metallic contacts seperated. When the styrofoam melts (because of gasoline) the contacts are released closing an electrcal circuit. The car's electronics would notice that the voltage has dropped across the contacts and would then shut off the fuel pump saving the day!

Perhaps there the airlines can adopt a version of this to protect their jet engines from miss-fuel events

Although the use of MTBE has likely been replaced by ethanol due to the impacts on aquifers of gasoline storage tank leakage. I found an article from the high days of MTBE contamination indicating evidence that it was common to find MTBE contamination in middle distillates. Although mostly about LUST the article states:

The source of the MTBE contamination of diesel fuel and heating oil is currently not known. Contamination could result from the use of similar
lines or vehicles during transportation from the refinery to end users. The presence of MTBE in fuel oil and diesel fuel is troubling, not only because it indicates that potential sources of MTBE contamination are widespread, but also because it could well result in increased remediation costs form heating oil and diesel fuel releases and increased litigation between home owners, insurance companies, and oil companies.

Here is a like to the article:

http://www.epa.gov/oust/mtbe/LL32heatoil.pdf

This article does give more weight to VW's contention that diesel fuel gets contaminated with gasoline. But I would turn this around by arguing that, if this is a known issue, than VW / Bosch would be under more onus to develop a pump design that is robust enough to handle some cross contamination.

 

[Jack Frost]

I forgot, we already have a gasoline sensor in our CR TDI's .... it is called a HPFP!

If the HPFP detects gasoline in the fuel, it will start shedding metallic particles that will result in a drop in fuel pressure. The engine's computer, detecting the drop in pressure will throw a cell light, put the engine into limp mode, thus containing the contaminated fuel within the fuel tank allowing our dealership to examine the fuel and disposing of it in a safe environmentall friendly manner.

 

[manual_tranny]

I forgot, we already have a gasoline sensor in our CR TDI's .... it is called a HPFP!

If the HPFP detects gasoline in the fuel, it will start shedding metallic particles that will result in a drop in fuel pressure. The engine's computer, detecting the drop in pressure will throw a cell light, put the engine into limp mode, thus containing the contaminated fuel within the fuel tank allowing our dealership to examine the fuel and disposing of it in a safe environmentall friendly manner.

I'm laughing and crying at the same time....

 

[emdeeaitch]

Yet another new part number...

For those not following BrokenTDI's "Canadian" thread, I just want to copy another part number into this thread:

A dealer in Washington state told BrokenTDI that 03L-130-785-A had superseded the original (I believe the original is 755 in place of 785). Is this a legit new part or a mistake?

 

[GraniteRooster]

I'm laughing and crying at the same time....

Me too! So funny, so true.

P.O.S. VW.

 

[eddif]

I want to try and look at the differences in the various followers that run on the cam in the HPFPs. This is way outside my ability to totally just come up with a correct answer, but it is interesting to look and know that there is an answer.

The first post shows flat follower faces (?). Not all the slider is shown.

Then a post by Honeydew that shows a different roller assembly.

Then our roller assembly

I wonder what design follower would actually work in our pump:
1..How much would the cam lobe have to be off-set to accomplish spin with a flat follower face (would a DLC coating work)?
2..Would a spacer and different roller diameter work?
3..How about a stabalized roller (no spin) of a different diameter with a spacer?

Some of this has been mentioned before by several people. But the difference in other pumps is finally posted and I am curious how to actually accomplish a revision.

If not a revision for the 4 cylinder VW CR HPFP, then is there a two cylinder pump that is compatable with a four cylinder single rail CR system:
1..Do you have to have 2 rails to run a 2 cylinder pump?
2..If 2 rails are used does that get into electronics and a whole host of duplicate parts?
3..If two cylinders were to feed a single rail, how many extra parts (mechanical and electronic) would be needed?
4..Are we stuck with a single cylinder pump given the electronics, and parts on board the 2009+ cars?

I do not know about all this for sure. In my mind all that can be done is a different modified roller assembly. Anyone with a better design, after looking at posts?

eddif

 

[eddif]

Cermet (composite)

I wonder if a solid cermet (composite) holder for the roller would be the Grace we are looking for. Looking at the photo the VW coating (hard carbon?) is just not up to the task at hand? If made from a cermet it might could be sent back in for an oversize roller if the roller ever failed (?).

The coated steel just does not seem to work. A cermet holder might just work. Does anyone have any dealings with cermet products? I know some followers have been made from cermet that work on air-cooled VW cams. Expensive but they do work.

eddif

 

[eddif]

Maybe Schubeck RollerX Lifters could design a roller that would work. For all I know you might could fit the roller assembly end in our sliders. Just to bring up a previous idea.

Instead of totally depending on VW, I think we should still be thinking of filtering and modifications of all sorts.

eddif

 

[Elfnmagik]

May have been already posted, but I find this very interesting.

http://delphi.com/about/news/media/pressReleases/pr_2010_05_11_001/

 

[Niner]

SQuare roller follower, black material for the follower, and what kind of pressure does it generate?

 

[kjclow]

2000 bar according to the article. Wonder if it can be made to replace the current bosche pump?

 

[emdeeaitch]

SQuare roller follower, black material for the follower, and what kind of pressure does it generate?

While we certainly all appreciate having hi-rez images available, please do not put such large images directly into the page. Rather, please set it to open in a separate window. You are breaking our viewing experience. I cannot read these pages without scrolling back and forth for every single line of text.

 

[specsalot]

Elfnmagik - Thanks for posting this good news. If you posted it here before, I can't believe I missed it. What a sad day for Bosch. Perhaps Delphi just works cheap. In any case good news is on the horizon.

Release Date: May 11, 2010

From the press release

"PARIS — Delphi Corp. and Volkswagen have developed one of the "greenest" diesel systems ever produced with the new 3-cylinder VW Polo BlueMotion..."

"After more than a year of co-development with Volkswagen, Delphi, a global leader in diesel engine management systems, is supplying its Multec® Diesel Common Rail System for the new 1.2-liter, 3-cylinder Volkswagen Polo BlueMotion."

"This is Delphi's first diesel Common Rail program with Volkswagen and it is on a vehicle that is now the most economical five-seater with the lowest emissions and the 2010 World Car of the Year. This is an excellent match for our technology."

"On later 4-cylinder engine applications, one further advantage will be the opportunity of running the pump at engine speed in combination with a twin cam lobe to generate pumping synchronized with injection."

"The design safely prevents the shoe on the DFP6 pump from lateral rotation which eliminates the risk of fatal pump damage and allows for a mass of just 2.4kg."

Looks like VW is in the process of executing a planned jumping of ship away from Bosch. Perhaps this is why Bosch has only produced what appear to be 'so-so' revisions to our HPFP that don't seem to be fixing much. This looks like a much more swarf resistive design. Now all they have to do is scale it up to 4 cylinder displacement. This might be good news for MY 2014 or 2015 Golf owners, but that will still leave most current owners holding the short end of the stick.

Let's start a sign up sheet for the 2L 4 cylinder version. Who knows maybe VW will give us all a free Delphi HPFP pump for Christmas one of these years. Perhaps some of the lawyers or marketing folks out there can convince VW its in their best interests to do so.

 

[eddif]

While we certainly all appreciate having
hi-rez images available, please do not put such large images directly
into the page. Rather, please set it to open in a separate window. You
are breaking our viewing experience. I cannot read these pages without
scrolling back and forth for every single line of text.

I often feel like the photo width patrol officer. 700 pixels wide is great for
most photos. Then you can personally blow the photo up for details.

eddif

 

[GraniteRooster]

Niner, please resize that image - its obnoxiously wide, screws up reading the thread. Thanks!!

 

[Honeydew]

Cp4.2

The Bosch CP4.2 is used on the 3L TDI as well as the 6.7L Ford.

There have been some reported 6.7L HPFP failures/dealer replacements but frequency of occurrences seems to be less than with the 2L TDI CP4.1.
The Ford system uses a 10 micron primary filter/water separator/WIF sensor and a 4 micron secondary filter. For those interested, much more detail can be found in the .pdf located here.

 

[specsalot]

Honeydew - Great pic's and detective work. I've just started skimming the 6.7L PDF - It looks like Ford anticipated many issues that VW is only just beginning to reconcile. Thanks for this great posting

 

[specsalot]

I wonder what design follower would actually work in our pump:
1..How much would the cam lobe have to be off-set to accomplish spin with a flat follower face (would a DLC coating work)?
2..Would a spacer and different roller diameter work?
3..How about a stabalized roller (no spin) of a different diameter with a spacer?

Some of this has been mentioned before by several people. But the difference in other pumps is finally posted and I am curious how to actually accomplish a revision.

If not a revision for the 4 cylinder VW CR HPFP, then is there a two cylinder pump that is compatable with a four cylinder single rail CR system:
1..Do you have to have 2 rails to run a 2 cylinder pump?
2..If 2 rails are used does that get into electronics and a whole host of duplicate parts?
3..If two cylinders were to feed a single rail, how many extra parts (mechanical and electronic) would be needed?
4..Are we stuck with a single cylinder pump given the electronics, and parts on board the 2009+ cars?

I do not know about all this for sure. In my mind all that can be done is a different modified roller assembly. Anyone with a better design, after looking at posts?

eddif

Missed this posting page - here are belated responses

On rails / telemetry - I think the choice of rails is based on them being located closely and conveniently to injectors. V engines need 2 rails. My Jeep has the 3 cyl pump but only one HP discharge line. IIRC the second rail is fed form a cross over line connecting it to the first rail. Look at the Ford 6.7 pdf honeydew posted - lots of answers there.

On follower design - I never really grasped the comments about 'offset' in this thread. Everyone large engine I've seen has the axial centerline of the follower assembly intersecting the centerline of the cam. I don't understand what the reference to 'offset' apply to. With the HP head and spring removed, spining the CP4.1 by hand, the follower rotates back and forth a bit. A little downward pressure on the follower stops the rotation. If the captive roller were to lose parallelism with the cam face, it looks like it would immediately be shifted 90 DEG. Once its 90 DEG out, I have no idea what would ever bring it back. I think that kind of event is part of the end-game of failure. The Delphi DFP6 design addresses a lot of design issues. So far it's not been deployed in production on the 2.0L I4 engines. Keep an eye on the Passat - it looks like the first candidate for it.

 

[eddif]

Missed this posting page - here are belated responses

On rails / telemetry - I think the choice of rails is based on them being located closely and conveniently to injectors. V engines need 2 rails. My Jeep has the 3 cyl pump but only one HP discharge line. IIRC the second rail is fed form a cross over line connecting it to the first rail. Look at the Ford 6.7 pdf honeydew posted - lots of answers there.

On follower design - I never really grasped the comments about 'offset' in this thread. Everyone large engine I've seen has the axial centerline of the follower assembly intersecting the centerline of the cam. I don't understand what the reference to 'offset' apply to. With the HP head and spring removed, spining the CP4.1 by hand, the follower rotates back and forth a bit. A little downward pressure on the follower stops the rotation. If the captive roller were to lose parallelism with the cam face, it looks like it would immediately be shifted 90 DEG. Once its 90 DEG out, I have no idea what would ever bring it back. I think that kind of event is part of the end-game of failure. The Delphi DFP6 design addresses a lot of design issues. So far it's not been deployed in production on the 2.0L I4 engines. Keep an eye on the Passat - it looks like the first candidate for it.

The comment on off-set was based on the fact no rollers were shown in one of the drawings in post 1125. Perhaps the draftsman was trying to simplify the see-through aspect of the CP3 pump, and left the rollers off. If the pump does have flat (non roller followers) then there would have to be off-set to cause the flat followers to rotate for the least wear. There are ways to draw things indicating spaces for left off parts. I really do not know, but was commenting based on the drawing as presented. VW used a flat follower on the HP gasoline pump, and it has since had an aftermarket designed roller replacement using a spacer and machine work.

On a pump compatable with the 4 cylinder engine:
There are different pump rotation speeds available as you switch to multiple pump head designs. The 4 cylinder would use (?): Two inline HP pump elements; Two opposed HP pump elements, Four HP pump elements. With all sorts of cam configurations. It appears that the HPFP CR systems sometimes depends on high speed when the pressure gets up to 26,000 psi. However unit injectors do not depend on speed. There are multiple options, but if the pulses are to agree with the correct injection point some V-engine pumps with three lobes will not just bolt on.

We need a lot more information to start swapping pumps.

The added filter option still seems the most reasonable owners option at this point. There would seem to be no electronic tune needed once your pressures were set to stock values.

eddif

 

[sirpuddingfoot]

The Bosch CP4.2 is used on the 3L TDI as well as the 6.7L Ford.
There have been some reported 6.7L HPFP failures/dealer replacements but frequency of occurrences seems to be less than with the 2L TDI CP4.1.
The Ford system uses a 10 micron primary filter/water separator/WIF sensor and a 4 micron secondary filter. For those interested, much more detail can be found in the .pdf located here.

Weird, I just happened to be looking for some info on the "dual boost" turbo used in the new 6.7 and noticed one of the threads in a forum had the same familiar "HPFP failures" heading.

The entire thread seems to follow much of what the debate has with the TDI HPFP failure: wear scar, added lubricity with additives required, etc.

The PDF link Honeydew posted doesn't take me to a PDF, but there is a link on the ford forum that takes me to a PDF with some interesting pictures and many notes about the issues.

Post #40 of the previous forum link has a PDF with some seriously bad news for US Bosch Diesel HPFP owners since it shows hugely increased wear with US spec diesel.

BTW, the CP4.2 is also used in the latest Duramax as well.

 

[Honeydew]

The PDF link Honeydew posted doesn't take me to a PDF,

It goes to a page of various manuals in from which the 6.7L (20mb) must be selected. Clicking on the 6.7L manual downloads that pdf.

Speaking of parallels to discussion here, check out this locked thread, also from FTE.

 

[specsalot]

...
We need a lot more information to start swapping pumps.
The added filter option still seems the most reasonable owners option at this point. There would seem to be no electronic tune needed once your pressures were set to stock values.
eddif

Thanks for clarifying the offset comments. There are other comments way back in this thread that I need to ponder a bit more. Taking on this thread is like reading a book. It took me 3+ days to end to end it when it was ~ 46 pages long. Pretty intimidating to the casual reader, but full of good insights.

As far as I can see your sentiments above remain the clearest reflection of current status on this issue.

Bosch hasn't really left a lot of room to accomplish a significant internal rework of this pump. The risk to boring / sleeve of the follower bore is how much it impacts the overall ability of the pump to handle the thrust loading. A good solution really needs to address potential rotation of the follower. Finding a way ( as a retrofit) that does not create another source of swarf will be a challenge.

Delphi seems to have a home run on their hands, but it remains unproven so far. If it can be shown capable it represents the long term solution.

I like supplemental filtering because it limits failures to being just pump failures rather than being complete fuel system replacement events. If it's feasible to refit the pump to oil lubrication, that should help. Improving maintenance through the following third party services will also help:

1. Pump inspections to illuminate internal condition.

2. Cleaning / flushing of the LP casing.

3. Periodic replacement of the follower piston / roller assembly using after market or Bosch OEM components based on Internal conditions.

These are not the best solution elements but may be the most easily attainable ones pending a real solution from VW. The challenge for owners is finding a way to hang on until a real root cause fix is in place. Given the 150,000 km VW stated longevity I'm not sure VW will be doing anything here with out a gun to their head.