Inside the HPFP

[TDI2000Zim]

So, i have an extra HPFP/CP4 with an unknown number of miles on it. i thought with all of the questions and concerns about this pump, i would show you all what makes this thing tick and disassembled it and photographed it.

if any administrators want to integrate or move it into any of the other numerous HPFP threads then feel free.

this is the label on the side of the pump. if anyone knows how to read this and determine what revision this one is or any other information please let us know.

this is the pump.

as a comparison, here is a CP3 next to the CP4. bonus points for anyone who guess what the CP3 is out of

this is what the inside looks like and the fuel flow

and an image borrowed from another thread. this is a nice computer model showing the insides

Fuel pressure regulator valve. this is what meters the amount of fuel that makes it into the plunger. more fuel will increase the pressure, less fuel will lower the pressure. i believe this works the same as the CP3. ie: with pulse width modulation. lower duty cycle will open the valve and increase fuel flow. higher duty cycle will close the valve more and restrict the amount of fuel going to the plunger. item 3 from image above

the FPRV is protected by a fine mesh screen on the input side of the regulator.

this is the spot that the FPRV bolts up to. you can see some fuel supply channels machined into the body. the hole in the top is the supply and the hole in the bottom is the exit to the plunger

plastic cover over the high pressure portion of the pump. this is easily removed with a screwdriver prying up between the discharge and the plastic cover

ta da!

When the dust settles, I wonder if VW playing around with Bosch's software was at the root of the HPFP/CP4 problem

...

“Citing unidentified sources, Bild said Bosch had warned Volkswagen as early as 2007 that its software should only be used in company tests and not for normal driving.”
​

 

[turbobrick240]

I think the relatively poor pump design of the cp4.1 and Bosch's warning to vw about the emissions testing defeat software are completely unrelated.

 

[jason_]

I have to ask.

How is Bosch making certiwn the piston and roller is guaranteed to not clock in the bore? Straight up luck? I seem to think all the cp4s that grind themselves is because there's an axis problem....not a material hardness/wear problem. Unless there's documented evidence that someone tore apart a failed pump carefully, and noted piston/roller position in regards to lobe.


I also notice every roller lifter in regards to cam shafts I've tore into has a fork or something similar to keep it from rotating in the bore....

 

[Rub87]

In you look into more deeply you will see that there is only an inifite small crank angle window where there is no rotation moment apart from bore friction to turn the followe. This happens 4 times per cam revolution, but as this window is infinite small and there is no moment of rotation acting on the follower it seems unlikely it could turn.

If you compare to a engine cam there is a very large window where the is no moment required to turn it.

Not really compareable imo.

 

[jason_]

So what's causing some of these pumps to have the assembly clock enough to cause problems? The bore wearing and getting sloppy?

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[Rub87]

That i do not know, but if the friction coefficient of the roller gets unequally over the width it wil have a chance to turn at 4 times per rev. Lets say a grain of sand end at one side of the roller it wil make it turn..

 

[jason_]

Yes yes. It's on center so precisely any drag from center, especially near end, will encourage rotation.

Still I don't see why they didn't engineer a way to stop any possibility of clocking. Sounds stupid in my opinion, especially something that floats on a floating pin! It's like rolling on a log that's above the water, on another log in the water. Almost impossible. Maybe it is, but point being.....

Anyone one, including ignorant people, know if you strip lubricity, and make tolerances tighter, you're going to have more fiction and headaches. Guaranteed.

And then build something with such possibility of failure.

Essentially they dug a hole with no wall for cave in protection. Luck of the draw as far as I can tell.


And the way the filtering is on these cars oem setup, fuel from the cp4 housing that's possibility contaminated, mixes with the filtered fuel that's on its way back to the rear of car, to get sucked again, that's if the aux pump doesn't catch it first just to pump it into the cp4 housing again, to exponentially grind it faster.....


If you see flakes in your canister, you're already fuked. Those flakes already came from cp4 housing, didn't get filtered, went back to the fuel tank, then got pumped up front to get settled in bottom of filter canister, before the oem filter. Ignorant design. 'nuff said.

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[roostre]

It is amazing that it works as well as it does or even at all.

Bosch and VW get an F grade for this in my book.

 

[tdiatlast]

Yes yes. It's on center so precisely any drag from center, especially near end, will encourage rotation.

Still I don't see why they didn't engineer a way to stop any possibility of clocking. Sounds stupid in my opinion, especially something that floats on a floating pin! It's like rolling on a log that's above the water, on another log in the water. Almost impossible. Maybe it is, but point being.....

Anyone one, including ignorant people, know if you strip lubricity, and make tolerances tighter, you're going to have more fiction and headaches. Guaranteed.

And then build something with such possibility of failure.

Essentially they dug a hole with no wall for cave in protection. Luck of the draw as far as I can tell.


And the way the filtering is on these cars oem setup, fuel from the cp4 housing that's possibility contaminated, mixes with the filtered fuel that's on its way back to the rear of car, to get sucked again, that's if the aux pump doesn't catch it first just to pump it into the cp4 housing again, to exponentially grind it faster.....


If you see flakes in your canister, you're already fuked. Those flakes already came from cp4 housing, didn't get filtered, went back to the fuel tank, then got pumped up front to get settled in bottom of filter canister, before the oem filter. Ignorant design. 'nuff said.

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...preaching to the choir. This has been discussed ad nauseam since some time back in 2010...

 

[jason_]

...preaching to the choir. This has been discussed ad nauseam since some time back in 2010...

Ok

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[MK4oilburner]

In regards to what could cause the tappet/roller to turn the wrong way on the lobe, when a spring is compressed the top and bottom surfaces rotate respective to one another no? So if there is no thrust bearing to allow the top and bottom surfaces to rotate as the spring is compressed the spring could enact a rotational force on the tappet as it travels down and while it's on the flat area between lobes the tappet/roller could rotate.

 

[_Blade_]

Hello, everyone.This thread has lots of educational material.After reading this,i can say that i know more about HPFP than before.I have a question, which i can't find an answer.Is the CP4.1 in CR engines built after 2013 timed to the injectors, or their only function is to maintain a constant pressure in the fuel rail?

 

[2004LB7]

I am pritty sure that the high pressure fuel pumps in these engines are the same for 2009 to 2014. Of this is true then thay will be timed to the injection events. I don't know what the 15s are like

Also, the timing of the pump is not as important as many would believe. It is likely more to do with emissions then proper running of the engine. The pump could be way off but you would likely never know it.

 

[GoFaster]

They are "roughly" timed to injection events in the interest of steadier rail pressure. It is not critical as it was with old style injection systems and it has no bearing on actual injection timing.

 

[2004LB7]

that is pretty much how I understood it

 

[heykw]

I can't believe they got away with this design.

 

[_Blade_]

Just for the sake of fun; i logged my CP4 pressure and valve regulator with CRI2-18 injectors. It running a stage 1 tune.

I always thought that rail pressure was constant across the rev range.Guess i was wrong. It might be like that to minimize energy loses.Higher rail pressure means more power drawn from the engine, equals lower overall mpg,right? So why not lower the pressure and increase injection timing if the rpm allows you to.

 

[Marius Titulescu]

I can't believe they got away with this design.

Tell me about it. Risky to say the least.
____________________________________
Marius from NTT Data

 

[HI73CH]

Hey guys, Sorry to rehash a 2-3 year old topic, I know from reading this thread that an adaptor was made and fitted to a Bracket, but did anyone ever fit and Run the CP4.2 pump. 2nd to that, did anyone Try and run a CP4.2 cam in the CP4.1 body, as was previously discussed earlier in the thread.

 

[Rub87]

cp4.2 is same **** design as cp4.1 so I dont think anyone ith logic sense would consider it as an upgrade and spend the effort to fit it

 

[HI73CH]

Thanks Rub87, In Australia, we have pretty good fuel 99% of the time, and in my experience we have far less Pump failures, usually caused when some twat puts Petrol (Gasoline) in there tank.
I have noticed that several specialty Tuners in the US are machining Stroke'r Cams for the CP4.2 pumps for Race/High powered trucks.
I thought I might give it a go in order to get a bit more fuel. If I was to use the Cam and Front Cover From the CP4.2 Pump reviewed earlier in this thread, in My CP4.1 Body, with a Spacer to move the pulley back to the same position. with more Stroke in the plunger, and a tweak to the tuning, it should be "bolt On"! I was just hoping someone had given it a go before me??

 

[turbobrick240]

Everyone who wants more fuel is running a CP3. Much better pump.

 

[Pip]

Help help hpfp golf mk7 2015 1.6 Tdi 81 kw

What do I do my hpfp failure on my 2015 vw golf 1.6 tdi 110 bph 81 kw anybody know what I should do there is only 144,00" kilometres on the car I am stuck

 

[jason_]

See if vwoa will cover anything,

If not then New filters. Flush the lines. Clean/replace injectors.

New cp4 or attempt cp3 conversion

Somewhere I have a total parts bill quote for a hpfp replacement from dealer.

Just the parts without labor is well into $3500.

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[Tin Man]

BMW just sent me a letter stating my CP4 (535d LCI) will be warrantied for 10 years/120,000 miles.

My question is does this mean I should sell the car some time later, say, at 200,000 miles? (the car would be worth around $10,000 by then) Or is there a "smart" way to prevent trouble, like replacing the fuel pump before it blows up? It was moved aft in the engine, so removing the engine is required I believe.

Sheesh.

 

[calimustang]

He said it spot on! I had CP3 and it made the world of difference! smoother acceleration and quicker starting. That was in my 2011, will do the same to my 2014 someday.

Everyone who wants more fuel is running a CP3. Much better pump.

 

[GoFaster]

BMW just sent me a letter stating my CP4 (535d LCI) will be warrantied for 10 years/120,000 miles.

My question is does this mean I should sell the car some time later, say, at 200,000 miles? (the car would be worth around $10,000 by then) Or is there a "smart" way to prevent trouble, like replacing the fuel pump before it blows up? It was moved aft in the engine, so removing the engine is required I believe.

Sheesh.

I know nothing of the BMW's particulars.

The VW experience has been that pre-emptive replacement is not a good plan. you have a "good" HPFP it may never break. If you have a "bad" HPFP it will fail early. An attempt at a pre-emptive replacement could very well replace a "good" one that would have never failed, with a "bad" one that ends up failing early. Opening a fuel system like this always has a risk of introducing contamination on account of the job itself.

If I were in your position ...

See if there is anything akin to the 2micron extra filtration kit available for that car. Or a CP3 "downgrade". I have my doubts but you never know. No idea how much support there is for that engine on this side of the pond.

Replace fuel filters on schedule. But don't over-replace filters ... because every time you open a fuel system like this introduces a risk of contamination on account of the job itself. Just follow BMW's schedule and use good quality parts.

Use good fuel, be darn sure of it, and keep your receipts.

If the HPFP blows up at 200,000 mi and it's substantial labour to replace it, it might not be worthwhile to fix.

Personally? I won't own anything that has a Bosch CP4 fuel injection pump in it.

 

[Tin Man]

Thanks! I'll see what happens. The car only has 54K miles on it.
I'm very picky about what fuel it gets - brand name and/or top tier companies only. Shell seems to have the BMW franchise lately so that is another plus. Around here, Shell is less expensive than off-brand, so its a no-brainer.
At higher mileage, my German mechanic (from Bavaria) likes to buy my cars since I take care of them and they are diesels.

 

[kjclow]

What do I do my hpfp failure on my 2015 vw golf 1.6 tdi 110 bph 81 kw anybody know what I should do there is only 144,00" kilometres on the car I am stuck

See if vwoa will cover anything,

If not then New filters. Flush the lines. Clean/replace injectors.

New cp4 or attempt cp3 conversion

Somewhere I have a total parts bill quote for a hpfp replacement from dealer.

Just the parts without labor is well into $3500.

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Won't do Pip much good to call VWOA, he's in Ireland. The list of parts to replace would still be good though.

Pip, Try reaching out to your local VW customer service. It might help or you may just be told to push the thing into the sea.

 

[Pittdawg]

Does anyone have any experience with the CP4.1/CP4.2 upgraded metering valve from Darkside?

https://www.darksidedevelopments.co.uk/products/cp4-hpfp-metering-valve-upgrade.html