CR engine HPFP analysis

eddif said:

T

Major theories:
1... It is about Lubrication (I agree)
2... It is about fuel filtering
3... It is about water seperation and water draining / removal
4... It is about fuel quality (especially with the stock HPFP)


I know I left out many that said the same things (possibly you were first). I hope you chime in and expand on your original thoughts.

eddif

Click to expand...

Eddif, appreciate your time and effort pulling this together.

As I read all of this (and consider what actions I should or shouldn't take with my own 2010), I think 1, 3, and 4 above are clearly interrelated. #2 is about preventing catastrophic damage after the failure of the HPFP caused by a combination of #1, 3, and 4.

Some combination of poor fuel (through extremely low lubricity fuel caused by un- or under additized ULSD, excessive moisture/water in the fuel that isn't removed through water separation, or introduction of RUG) and a HPFP design that lives within a very narrow design margin that fails with catastrophic consequences. Filters would mitigate the consequence but may not prevent the cause of the failure. Water separating filters may reduce the likelihood of failure but not the consequence.

For now, my car seems to be running very well on a combination of 1-5% bio for lubricity. If my theory holds, lubricity significantly reduces likelihood but not consequence. It is also one of the few things I can do without modifying the vehicle or compromising my warranty in any way.

I was aso wondering about the emulsifiers/de-emulsifiers put in the fuel by the fuel providers. If an emulsifier is used I can understand why the fuel filter does not catch the water, the emulsified water droplets are finer than the filter. Also since there is no decent water seperator system the water and fuel mix go to the HPFP and bang your done. So I'm thinking most fuel providers use emulsifiers, we need to verify this. De-emulsifiers would just seperate the fuel and water and sink it to the bottom of your fuel tank.
So this got me thinking what if some fuel providers are using de-emulsifiers and you fill up with this fuel, water sinks to the bottom of your tank. Then you use fuel from a provider that uses emulsifiers. Well that is just going to emulsify whats been sitting at the bottom of your tank. This is how I can see the cloudy fuels showing up.
So I figure to start we need a better filter and water seperator system, especially for emulsified fuel systems since these water droplets will pass through the filter and must really become a disaster at high pressure with all that heat.
Next since the HPFP is very sensitive I would probably have another filter on the low pressure flow side, and for extra precaution for when the HPFP will destroy itself or fail after 200000miles, a high pressure filter to save the injectors and return system.

there is no reason for fuel to go thru the cam/roller area other than for lubrication correct? why not bypass the low pressure chamber altogether for engine operation and supply a lube feed to the low LP chamber that returns back to the tank(thru a filter of course). even if it is taken this far , you could even use engine oil from the crankcase for the lube. the only fly in ths ointment though, where is the fuel "metered" for the high side?

I wonder if a CP3(HPFP) off a Cummins could be retrofitted in place of our current pump? I am on Cumminsforum and have only heard of a couple trucks that had a CP3 issue. I know that the 6.7l CP3 would be WAY overkill but the QSB3.3 cummins is closer in displacement and is still a common rail.
I also have the Idea of mounting an Airdog II back by the tank and bypassing all the stock fuel system up to the HPFP, then using the stock filter as a return. I don't like VW's lack of water seperation in their design and the ADII would give us 2 micron fuel filtration AND water separation!

I have been reading:

http://www.dieselplace.com/forum/archive/index.php/t-984.html

So it looks like some fuel companies use de-emulsifiers, and some use emulsifiers. Also some additives are either or. So Either we have water at the bottom of the tank or water mixed in with the fuel. Now how about bacterial growth because of the water? Would explain some of the funky rusty crap we have seen in some filter housings? We must find out more about service stations and how they handle the water in their tanks?

I got a feeling the HPFP does not tolerate water at all especially at high pressure. With the heat and pressure can the emulsified water in the fuel
seperate, become vapor prior to the injectors and inside the pump causing the lack of lubrication?

ziggy55 said:

I have been reading:

http://www.dieselplace.com/forum/archive/index.php/t-984.html

So it looks like some fuel companies use de-emulsifiers, and some use emulsifiers. Also some additives are either or. So Either we have water at the bottom of the tank or water mixed in with the fuel. Now how about bacterial growth because of the water? Would explain some of the funky rusty crap we have seen in some filter housings? We must find out more about service stations and how they handle the water in their tanks?

I got a feeling the HPFP does not tolerate water at all especially at high pressure. With the heat and pressure can the emulsified water in the fuel
seperate, become vapor prior to the injectors and inside the pump causing the lack of lubrication?

Click to expand...

There is also "solubilizer" as used by Power Service.

http://forums.tdiclub.com/showthread.php?p=3136217

Can it also be possible that there is some incompatabilities between fuels from different providers. Especially when we look at diesel. The possible blends of different forms of biodiesel, regular diesel, additives and then end user additives, there is some room for error and incompatable mixtures here.

Hang in there folks. There will be some negative comments when I discuss drilling and tapping holes in the HPFP to get the fuel routed through filters. Of course that will be after we have drawings and photos.

scrappytdi said:

there is no reason for fuel to go thru the cam/roller area other than for lubrication correct? why not bypass the low pressure chamber altogether for engine operation and supply a lube feed to the low LP chamber that returns back to the tank(thru a filter of course). even if it is taken this far , you could even use engine oil from the crankcase for the lube. the only fly in ths ointment though, where is the fuel "metered" for the high side?

Some of this is my opinion and not possibly in the textbooks.

Every amount of churning you can do to diesel right before injection can be good. Any water, air etc is mixed to the maximum. Moisture slides through better when mixed to the maximum. Churning also heats the fuel. Where I live you could probably just use the electric pump in the engine compartment, bypass the lower HPFP cam area and do just fine. I suggested this before and see nothing wrong with the thought. In cold areas though you need the churning plus a heating loop to keep the diesel liquid.

The electronic controlled valves take care of the metering. You would have to use intelligence in doing the new fuel path. Speaking of the fuel path we need drawings desperately to be able to work some of this out.

I wonder if a CP3(HPFP) off a Cummins could be retrofitted in place of our current pump? I am on Cumminsforum and have only heard of a couple trucks that had a CP3 issue. I know that the 6.7l CP3 would be WAY overkill but the QSB3.3 cummins is closer in displacement and is still a common rail.

I also have the Idea of mounting an Airdog II back by the tank and bypassing all the stock fuel system up to the HPFP, then using the stock filter as a return. I don't like VW's lack of water seperation in their design and the ADII would give us 2 micron fuel filtration AND water separation!

Some of the filtering problem is by-pass inside our pump, and some is outside. I feel after we learn our fuel flow path we will know more.

Click to expand...

ziggy55 said:

Can it also be possible that there is some incompatabilities between fuels from different providers. Especially when we look at diesel. The possible blends of different forms of biodiesel, regular diesel, additives and then end user additives, there is some room for error and incompatable mixtures here.

Click to expand...

There is no telling at all the differing additives that have been added. I vote for my working on the filtering, but fuel is sure a problem too.

eddif

eddif said:

I sure do not know it all. I do think that the amount of actual flow through the injectors is small. High pressure filters take an extremely thick case and special construction.

I suppose a low pressure filter that kept the lower part of the HPFP free of wear particles would be much simpler. If in fact the wear particles are created in fuel at < 120psi (?) then the filter would be much less complex. If the filter removed the wear particles before the conversion to 26,000 psi then there should be no wear particles going to the common rail or injectors. There has been no real description of wear starting in the high pressure part of the pump, but in the low pressure side where the cam and roller assembly are.

This is why I have requested those who might create our version of a fuel flow diagram would help. We could trace the pressure increases and path of the fuel for all to see. Right now it is almost impossible to do all the operational path with words, and a run to another web page.

If the fuel is clean coming into the HPFP (I think it is). Another filter leaving (or bypassing) the cam / lobe chamber would keep the fuel going to the high pressure part of the pump clean, and thus the injectors clean.

Then​

If the fuel leaving the low pressure side of the HPFP is filtered before making a loop back to the primary pump heating loop (?) then the filtering of wear particles will be started.​

Finally​

If all return fuel to the tank is filtered we should have captured most of the wear particles.
+++++++++++++++​

​

eddif

Click to expand...

1... Protecting the high side of the HPFP requires breaking the internal supply drilling from the overflow valve inlet that goes to the N290 fuel metering valve, and putting a 1 micron (?) filter in between the overflow valve and the N290.

2...Protecting the overflow valve from wear particles would require blocking the original inlet to the overflow valve (from the cam and roller chamber) and getting another source for the overflow valve and N290 valve. This source for the overflow valve would flow through another filter and into the overflow valve and head toward the N290 valve. This would actually double filter the fuel going to the high pressure side of the HPFP if you do number 1 above (Should be good thing to do).

3... Dealing with the original filter thermal part is a partial mystery to me right now. If you clean up the bypass valve source there should be no problem with the original filter as installed. ( Except for heat issues when you put another filter in the line that cools fuel).

4... If we find out the fuel would be clean by the time it hits the return line to the tank there would be no filter needed for the return line.

This can all be done with one extra filter by feeding clean newly filtered fuel from the cam roller chamber to the tee line leading to the overflow valve and N290 valve, or multiple filtering the fuel as outlined above. How safe do we want to be?

Boy we need drawings. I have to run back and forth to the VW design page to do this.

eddif

Talking to cardinarky who has spent many years working in steel mills,i got a new perspective on the potential reason for failure in these hpfps...

While I fully support and am looking foreward to your modifications edith, the argument that perhaps there were some poorly produced batches of steel that are causing/will continue to cause failures... Well it seems to make sense to me. If the coatings on the parts in the pump were done poorly, there is a very good chance that there would be some sort of cover-up. I'm starting to get the idea that there isn't any good reason for 2009-2011 owners to have misfuelled or found bad fuel any more often than the rest of us.

manual_tranny said:

Talking to cardinarky who has spent many years working in steel mills,i got a new perspective on the potential reason for failure in these hpfps...

While I fully support and am looking foreward to your modifications edith, the argument that perhaps there were some poorly produced batches of steel that are causing/will continue to cause failures... Well it seems to make sense to me. If the coatings on the parts in the pump were done poorly, there is a very good chance that there would be some sort of cover-up. I'm starting to get the idea that there isn't any good reason for 2009-2011 owners to have misfuelled or found bad fuel any more often than the rest of us.

Click to expand...

I enjoy your posts.

I am nobody from Mississippi. I do not have 10 letters after my name (of all the degrees I have). Take all these comments with that understanding.

I am for a more robust pump. This robust pump also needs filtering that will take care of wear materials.

We face many needs:
1... Robust pump
Design, Materials, Workmanship
2... Fuel quality
Lubrication, Cetane, Additive package, Few Contaminants,
Fueling importance for folks that have never owned a diesel and especially a diesel that will self destruct with wrong fueling.
3... Warm up loop for fuel
Filtering for wear prone system, Screens for low wear system
4... Filtering.
Primary original fuel, Return fuel
The more wear prone the more filtering needed


I understand your point of shoddy materials. I also understand I have just dealt with / dealing with the PD engineering mistakes. Although VW has done an excellent job on their engines; there are a few glitches from time to time (I have my own glitches so I understand and have compassion) . The containment filtering of wear particles seems to be one problem area in the present CR system. Time will tell which: the metals / clearances / coatings / filtering / design are at fault, and order them in importance.

In the present system, a filter that stays super clean while the injection system eats itself alive is a little hint I am exploring. If one extra filter will contain most wear materials, the existing materials may wear better. Although opinions differ, the roller may be the first to suffer (at this point we have differences of opinion, and it may be different failures at different times).

There are differences in the older models and the CRs.

1... The total pressures expected out of the designs are different.
Older models have less pressure for a short time.
Newer models maintain a higher pressure over longer time.
2...The 1.6 injection pressure was lower and depends on the fuel for lubrication of the whole pump. The 1.9 ALH style is still low pressure compared to the PD and the CR.
3... The PD series has the roller injection assembly lubricated by engine oil and seems to work fine with high pressures. There are two phases of the injection pressure too. The unit injector lasts a long time too. This system seems not seem to shed excessive wear materials.
4... The CR has the higher pressures but has the roller assembly lubricated by ULSD. The roller assembly is also expected to work over a longer degree arc, produces high pressure from a lower RPM, Maintains this pressure. The CR pump is creating wear on the cam and roller assembly. The wear materials are not adequately filtered out (go through whole system).

No pump may be ever modified, but going through all this will educate us to the system. Very soon many cars will be out of warranty. We are encouraged to prepare for when the owner is to take care of his possible problems.

eddif

Test run on start of identifying passages in pump. You never know where you might find someone willing to help. LOL

The supply port into the cam roller area is at 9:00 the port with the light showing through it (light dot) is the supply headed for the high pressure fuel control valve. The light dot would have to be tapped and plugged (?) and another supply found (?) (I really need a pump in my hand), but will work with what I have.

Thanks dweisel.

Edit: Nov 21 9:00 local 2010
Here is another photo of where the fuel control valve is mounted. The lighted passage is the fuel coming from the first photo.


eddif

eddif said:

Test run on start of identifying passages in pump. You never know where you might find someone willing to help. LOL

The supply port into the cam roller area is at 9:00 the port with the light showing through it (light dot) is the supply headed for the high pressure fuel control valve. The light dot would have to be tapped and plugged (?) and another supply found (?) (I really need a pump in my hand), but will work with what I have.

Thanks dweisel.

Edit: Nov 21 9:00 local 2010
Here is another photo of where the fuel control valve is mounted. The lighted passage is the fuel coming from the first photo.

eddif

Click to expand...

great pictures, now we need to see the 180 degree view of the pump. if there is light coming thru then there is a port all the way thru. and in the second pic, that passage is intersecting with the passage in th the pump housing first pic. it could be as simple as plugging the second passage and installing a fitting where the first comes out of the housing for lube flow. Then for engine operation, make an adapter that moves the FCA out of the housing and has an external inlet to the FCA.
or another option is to use the adapter as the outlet for the pump and inlet for the FCA. this way would allow the mod to be a complete "bolt on" without any modifications to the pump itself.
all this is dependent on clearance to allow for the adaper and one or two lines off it.
this would work if you wanted to put a filter inline also, run it out thru the fitting in the first passage(or the pump outlet in the adapter) and return it to the FCA thru the adapter after filtering.

Eddif you are correct most of the particles are formed on the low pressure side (from looking at the flow diagrams and pump construction). So if we place a filter around the area after the metering valve looks like a good place. If the low pressure side is the problem, the issue is heading more towards poor materials choosen for pump construction. I still think the filter system is poor. Standyne has a filter unit which has water seperator and heater all in one unit. Wonder if this would be a good replacement?
I think even if there was no issue with the pump, eventually this unit will fail, like any other pump. Issue is when it does happen how do we prevent the high expense? Simple answer would be filter out the particles before they have a chance to contaminate the whole system.

Thanks Eddif for putting you nose into this one.

I took a couple pics of the HPFP as installed in my car. I don't know if they are any help but I will post anyways.




based on looking at my car, putting a fitting on the back side and blocking the internal passage is going to be a tight squeeze, but it does look like ther is room to use the adapter under the FCA.

scrappytdi said:

I took a couple pics of the HPFP as installed in my car. I don't know if they are any help but I will post anyways.


based on looking at my car, putting a fitting on the back side and blocking the internal passage is going to be a tight squeeze, but it does look like ther is room to use the adapter under the FCA.

Click to expand...

I am trying not to decide on the fitting location / locations yet. I am encouraged that we will find this possible to do.

Your pictures are sure a help. Any pictures placed in at a maximum of 800 pixels wide will not effect most viewers. I suggest 800 because of the stone age programs I run. At 1023 the pictures are a little wide for my equipment. I recently had to get some more software so I could edit my photos (my previous program died).

Thanks

eddif

scrappytdi said:

great pictures, now we need to see the 180 degree view of the pump. if there is light coming thru then there is a port all the way thru. and in the second pic, that passage is intersecting with the passage in th the pump housing first pic. it could be as simple as plugging the second passage and installing a fitting where the first comes out of the housing for lube flow. Then for engine operation, make an adapter that moves the FCA out of the housing and has an external inlet to the FCA.
or another option is to use the adapter as the outlet for the pump and inlet for the FCA. this way would allow the mod to be a complete "bolt on" without any modifications to the pump itself.
all this is dependent on clearance to allow for the adaper and one or two lines off it.
this would work if you wanted to put a filter inline also, run it out thru the fitting in the first passage(or the pump outlet in the adapter) and return it to the FCA thru the adapter after filtering.

Click to expand...

Adapter? WOW!! Got to love a club effort.

eddif

eddif said:

Your pictures are sure a help. Any pictures placed in at a maximum of 800 pixels wide will not effect most viewers. I suggest 800 because of the stone age programs I run.
eddif

Click to expand...

I agree. Large pictures on older monitors really make the posts hard to read as the windows become large than the screen size. If you are on dial-up, they are impossible to download in any reasonable time. Although for some, money solves this problem easily; for many others, all the money in the world can't help them. Not all of us have broadband cable to the doorstep yet.

For a quick protection fix, by looking at the diagrams, we can place a filter on the return to the filter housing from the pump and injectors. Although with this we are still sacrificing the injectors. From what I can tell some of the return is dumped back into the filter housing and some goes back to the tank unfiltered by the filter housing. I wonder if Standyne or other manufactures can make a modified version of their heated fuel filter/water seperator unit with a valve as the factory unit.
An adapter that would go where the metering valve goes would be amazing. This adapter would bypass fuel to a filter. The metering valve then bolts into our adapter and receives only filtered fuel prior to entering the high pressure side.
I will be contacting a high pressure filter manufacture and see if they have something for us. Bolting in a filter between the pump and injector rail would be a plus.

ziggy55 said:

... I will be contacting a high pressure filter manufacture and see if they have something for us. Bolting in a filter between the pump and injector rail would be a plus.

Click to expand...

I recall that Pall's highest pressure filter falls short in the PSI department (max is something like 20K PSI) and it's large, like 7" or 9" long. I had a cut sheet on it, but tossed it. Maybe Schroeder or Hydac make something suitable.

Norman filters has a 30000psi unit. A little large 6.71 x 2.25. Will give them a call see if it will work in our application. Just like to know how we can pretest any solution prior to test on a vehicle. I figure most of us will not make any changes till after warranty. Also I'm sure most will be reluctant to be a test mule.

If I understand the operation of the HPFP per the study guide, the inlet to the metering valve never sees high pressure. The overflow valve on the inlet side opens at about 62 psi and sends excess fuel back to the return line.

So if one wants to stop metal from entering the metering valve, compression chamber, common rail and injectors, a more "normal" filter should work. One issue might be pressure drop across the filter installed just prior to the metering valve and possible effecs on fuel metering control. Ideally, the filter should be before the overflow valve as pressure drop is probably not a concern if installed there.

ziggy55 said:

(snipped) With the heat and pressure can the emulsified water in the fuel
seperate, become vapor prior to the injectors and inside the pump causing the lack of lubrication?

Click to expand...

Without a doubt, high localized amounts of emulsified fuel will have an aggressive solvency effect and cause lots of pitting/wear due to the water component flashing through steam/water phase boundaries (multiple). Think of it like cavitation^4.

I do not own one of these, but I would want a 2% biodiesel blend with a biodiesel-compatible demulsifying additive package and water separator if I did.

Plus 3 Golfer said:

If I understand the operation of the HPFP per the study guide, the inlet to the metering valve never sees high pressure. The overflow valve on the inlet side opens at about 62 psi and sends excess fuel back to the return line.

So if one wants to stop metal from entering the metering valve, compression chamber, common rail and injectors, a more "normal" filter should work. One issue might be pressure drop across the filter installed just prior to the metering valve and possible effecs on fuel metering control. Ideally, the filter should be before the overflow valve as pressure drop is probably not a concern if installed there.

Click to expand...

I would rather go this route, it seems most of the wear occurs in the cam/roller low pressure area so keeping it out of the high pressure area should help to prevent piston galling and contamination of the rest of the expensive to replace system. the filter required for this is inexpensive(relatively) and fairly compact.

eddif said:

Adapter? WOW!! Got to love a club effort.

eddif

Click to expand...

I have some ideas how to build it but have no way to put my ideas to use. The only thing I can do is sketch it out and scan it. I can explain it though if someone has access to cad/cam. I would also be willing to pull my metering valve(FCA) out to get pics/dimensions

While it is noble to want to filter the high side of the system [and it may seem to be a fairly easy thing to do] the fact is it will not work for a number of reasons.

I agree that the high pressure side type filter is a long shot and the most complicated and higher priced solution. The least expensive solution would be the filter on the low pressure side from where the metering valve is. Also we sill need a filter solution on the return to the filter housing.
Maybe we can sell the solution to VW, once figured out. ahahahha.

I think the HP (high pressure) filter is not needed. You are dealing with a very expensive piece of equipment that will cause pressure / etc. problems beyond belief.

The other aspect is the need of the high pressure filter. Anyone would think that a failed system needs the HP filter. There is wear material in the HP rail, injectors, etc of a failed system and you need to filter the wear material before it hits those items. Seems like a logical way to go. Where to put the filter is the question.

Here is what you are facing IMHO:
1... The HP part of the HPFP does not usually wear if it is fed clean fuel.
2... The HP part of the HPFP fails in a CR engine because it was fed dirty fuel. (aluminum, steel, etc. ground up / generated in the low pressure part of the HPFP). The only protection in a stock system is a screen assembly.
3... Filter the low side fuel going to the HP side of the HPFP and the HP elements of the HPFP will not rapidly wear. (add a new better filter)
4... Put trash into the input part (plunger) of the HP side of the HPFP and it will pump out trash to the rail and injectors. Put clean fuel into the input of the input of the HP plunger and clean fuel will come out at 26,000 psi.
5... Right now the only thing protecting the HP (high pressure) side of the HPFP is a screen. Add a 1 micron (?) filter there and you will reduce your HP problems to almost zero, and not need the HP filter. IMHO.
6... The odds on the new proposed filters saving any part of a dirty system is very, very low. Ultrasonic cleaning might help a tiny bit with new filtering system parts installed. Right now the stock system does not filter out wear parts and a whole system is always needed. New added filters might give some chance of helping some undamaged barely contaminated parts, but do not get hopes up.
7... The better the filter system added the more chance the CRs have. (the more filters without pressure loss the better)
8... The sooner you add the extra filtration the better chance you have. Wait for signs of failure and it is more than likely too late. A common action is to wait too late, and not admit that something should have been done sooner.

eddif

eddif said:

I think the HP (high pressure) filter is not needed. You are dealing with a very expensive piece of equipment that will cause pressure / etc. problems beyond belief.

The other aspect is the need of the high pressure filter. Anyone would think that a failed system needs the HP filter. There is wear material in the HP rail, injectors, etc of a failed system and you need to filter the wear material before it hits those items. Seems like a logical way to go. Where to put the filter is the question.

Here is what you are facing IMHO:
1... The HP part of the HPFP does not usually wear if it is fed clean fuel.
2... The HP part of the HPFP fails in a CR engine because it was fed dirty fuel. (aluminum, steel, etc. ground up / generated in the low pressure part of the HPFP). The only protection in a stock system is a screen assembly.
3... Filter the low side fuel going to the HP side of the HPFP and the HP elements of the HPFP will not rapidly wear. (add a new better filter)
4... Put trash into the input part (plunger) of the HP side of the HPFP and it will pump out trash to the rail and injectors. Put clean fuel into the input of the input of the HP plunger and clean fuel will come out at 26,000 psi.
5... Right now the only thing protecting the HP (high pressure) side of the HPFP is a screen. Add a 1 micron (?) filter there and you will reduce your HP problems to almost zero, and not need the HP filter. IMHO.
6... The odds on the new proposed filters saving any part of a dirty system is very, very low. Ultrasonic cleaning might help a tiny bit with new filtering system parts installed. Right now the stock system does not filter out wear parts and a whole system is always needed. New added filters might give some chance of helping some undamaged barely contaminated parts, but do not get hopes up.
7... The better the filter system added the more chance the CRs have. (the more filters without pressure loss the better)
8... The sooner you add the extra filtration the better chance you have. Wait for signs of failure and it is more than likely too late. A common action is to wait too late, and not admit that something should have been done sooner.

eddif

Click to expand...

So when do I come up and we perform surgery on my 2010 tdi golf? Least to see if I have wear at all....put in a filter, etc? Have things to monitor pressure drop, etc?

vschaos said:

So when do I come up and we perform surgery on my 2010 tdi golf? Least to see if I have wear at all....put in a filter, etc? Have things to monitor pressure drop, etc?

Click to expand...

Right now we are all on the search for the place and way to add the better filtering. Fortunately all this can occur at pressures usually under 80 psi. We do not need any real high tech methods. A guage before the filter and one after the filter tells if there is a pressure drop because of the added filter.

Warning: Stay away from the high pressure area. Do not even think of touching the HP part of the system (even in theory).

The checking for wear has been seen as possibly voiding warranty, although three (?) posts before that warning was a dealership (?) that did that very thing.

I am an outsider and I know it. I have been allowed to make comments and I appreciate it. What I have suggested is very radical and needs to be viewed that way. Radical, Radical, Radical. Taken that way though, you can plan for the day when warranty is gone and you are on your own.

If you wait till warranty is gone and then begin a year long effort to design a fix it is a lot late. I think I know where to drill and tap two holes in the HPFP to get this done tomorrow, but I have an obligation to the rules of this forum and other laws. As a technical exercise (as a test) it might be allowed, but restraint is in order. If this sounds like double-speak it may be. We have conflicting needs that need to be addressed and fulfilled.

I personally suggest no one modify another persons car. This is a technical exercise at this point. Hopefully it will help direct VW and they will take the actions needed. I am not waiting for them to think through the problem though.

eddif

eddif said:

I think the HP (high pressure) filter is not needed. You are dealing with a very expensive piece of equipment that will cause pressure / etc. problems beyond belief.

The other aspect is the need of the high pressure filter. Anyone would think that a failed system needs the HP filter. There is wear material in the HP rail, injectors, etc of a failed system and you need to filter the wear material before it hits those items. Seems like a logical way to go. Where to put the filter is the question.

Here is what you are facing IMHO:
1... The HP part of the HPFP does not usually wear if it is fed clean fuel.
2... The HP part of the HPFP fails in a CR engine because it was fed dirty fuel. (aluminum, steel, etc. ground up / generated in the low pressure part of the HPFP). The only protection in a stock system is a screen assembly.
3... Filter the low side fuel going to the HP side of the HPFP and the HP elements of the HPFP will not rapidly wear. (add a new better filter)
4... Put trash into the input part (plunger) of the HP side of the HPFP and it will pump out trash to the rail and injectors. Put clean fuel into the input of the input of the HP plunger and clean fuel will come out at 26,000 psi.
5... Right now the only thing protecting the HP (high pressure) side of the HPFP is a screen. Add a 1 micron (?) filter there and you will reduce your HP problems to almost zero, and not need the HP filter. IMHO.
6... The odds on the new proposed filters saving any part of a dirty system is very, very low. Ultrasonic cleaning might help a tiny bit with new filtering system parts installed. Right now the stock system does not filter out wear parts and a whole system is always needed. New added filters might give some chance of helping some undamaged barely contaminated parts, but do not get hopes up.
7... The better the filter system added the more chance the CRs have. (the more filters without pressure loss the better)
8... The sooner you add the extra filtration the better chance you have. Wait for signs of failure and it is more than likely too late. A common action is to wait too late, and not admit that something should have been done sooner.

eddif

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I agree with the argument that the metering valve filter would be all we need for the reasons listed above.

one negative side effect of the HP filter is an increase in rail volume. being that the HPFP is a mechanical pump and has a limit on how much it can flow there is the possibility that the filter will delay the injectors and rail pressure sensor seeing the commanded pressure rise and throwing a low rail pressure code. and at the other end of the spectrum it could cause the same problem with high pressure in certain conditions.
I also do not believe that a 30K rated filter is enough, there was a well known and respected guy in the Dodge Cummins circles that had a gauge made that could read up to 40K rail pressure. he installed it on a truck and reported that he saw 39K psi in the rail on shutdown. This was on a truck that had a 26K max rail pressure! The Cummins system might be different BUT it was made by Bosch also and from my quick look at my car uses several of the same components so I would be willing to be they are the same in how they operate.