I am experiencing hard to start when engine is cold problem. Recently I have replaced LPFP and fuel filter but the problem remains. High pressure fuel system fault was also triggered on couple of occasions.
Today I have removed HPFP and measured thermal expansion and it is 27mm. I assume that is not good?
I would like to try to rebuild pump myself.
Are you still running rebuilt HPFPs?

 

I have rebuild my pump 3 times and each time I got about 1500 miles out of it before it started to fail again to the point that the car was not driveable.

18mm is the correct measure and mine has been 27-30mm at quitting time. Your car will probably run ok for another couple hundred miles - apart from the hard starts - until the pump just can't make it go.

When it can't feed the Turbo anymore is one milestone and the next one is that it struggles to downshift when you give it gas to pass someone for example. After that it won't be long.

I have had fun rebuilding the pumpand avoiding that that huge expenditure for a new HPFP, comma but in the end that is what you're going to need. At least they are one of the easiest parts to change on the motor!

 

@tlbuss Thank you for a reply.

I suppose I should consider buying OEM one as when I monitor fuel rail pressure (actual and specified) when driving sometimes actual pressure is dropping below specified as well. And since I have random hesitation when driving I am guessing that HPFP adds to that problem as well?

 

I am pretty sure that your problem IS the HPFP based on your description. Occasionally you can get lucky with a remanufactured pump or a " new" one from China, But an OEM replacement is a sure bet if you don't have time to be messing with it.

 

12/11/22 --------- Time to refill this original 2008 pump again it ran for another 36,030 miles. Refilled at 92,033 miles--- 128,063 miles present. Curious to see the next run?

 

12/11/22 Time to refill the original pump again. Install at 92,033 miles and now have 128,063 miles. Curious to see if I can get another 36,030 miles on the original HPFP.

 

I used 50/50 ratio. I fill the body with STP and the center of the piston pumps then I fill the cap with Lucas while rotating the cam and I did notice you can fill the backside through the hollow shaft of the cam which acts as a crossover for the oil. Have the mounting flanges and screws in place on the cap ready for quick installation when you flip the cap and use a hand drill to install as quickly as possible. Make sure you pull the bolts down evenly so you don't damage the "O" ring. It's messy but compressing the oil in the chamber sets the expansion valve setting to about.750" or 19mm with a caliper. I have had good results by doing this so far. Only way I see the pump using oil is by it escaping through the seal under the drive that engages the cam when running. I have no leaks on the outside. Hope this helps ???

 

Filled the body with STP and the cap with Lucas so about 50/50

 

is it possible for fuel to leak inside oil in hpfp? i am trying to find why my car has high negative fuel trim, checked injectors, leak tested everything. i am at loss.

 

For general consumption: I recently joined a Mini Cooper Mechanics group on Facebook, and much to my surprise someone in there pointed someone else in there to an HPFP rebuilder. I can't vouch for this business, never had any dealings with them myself, but sharing just in case it may be of interest.

Link: https://hpfp-mini-cooper-rebuilt.com/

 

The HPFP is a separate unit from the engine driven by the cam. The bellows in the pump are known to wear out and this would be the only way for fuel to leak inside the pump and just replenishing the oil inside the pump would not work without replacing the worn-out bellows. Hope this helps.

 

Just wow. Some serious dedication in this thread. I've been researching to rebuild the hpfp on my BMW, and came across a site that has step by step instructions for both the mini and my 135i. After reading all twelve pages of this thread, I felt compelled to register, and share.

Hope it helps, and greetings from sunny South Africa.

https://beisansystems.com/n14-n18-hi...mini-cooper-s/

 

OMG. The discussion of Viton vs. Fluorosilicone is blowing my mind. I was **SO** close yet so far away. And yeah those Fluorosilicone rings I added (which, to be clear, were NOT the O-rings that were germane, as the article reveals) did in fact break down *on their own* over time as my HPFP museum literally sat on a counter for years. So I can validate that about the material wear, lol.

Thank you so much for the link. So very cool and such good info! And finally a full explanation for what breaks down inside, where, how, and why! I can stop obsessing now lol

 

Haha, I thought you might like that bit. I was particularly interested in the oil they used, and their filling method. Much simpler than all the other methods I have seen on youtube etc.

I just wish they had posted the sizes of the seals used!! A search on their site for the kit they apparently sell, brings up nothing unfortunately.

 

Hey guys! This topic helped me a lot. I'm just writing here so if someone has the same issue as me, and searches on it on google, he'll see this.

So my N14 Peugeot 207 had a stuttering issue. I could only use it on 1/4 throttle max , otherwise it would bog/stutter/ hesitate on acceleration/on load.

I have changed the injectors before, thought that was the problem but not.

Haven't had any symptoms on my HPFP at all. No cold start issues, so I didn't really think it was the problem until I checked live data while driving.
When the car hesitated, the fuel pressure dropped down almost to 0, then jumped up to the normal pressure.
Then yesterday I had a spare HPFP which had a 27mm diaphragm depth (which is not good). I took it apart, cleaned it, filled it with 75w-90 transmission fluid, put it back together.
I don't really know the history of this HPFP, but considering that the depth of the diaphragm indicated that its bad, I'm assuming it wasn't so good. After rebuild the depth came down to
13mm (which is way below the factory measurement). I didn't think much of it, it was already a spare so why not run it. Put it on the car, now the car doesn't misfires on idle, no hesitation at all.

I hope I helped. If you have any questions tag me.

Have a nice day.

 

Hey guys,

Thought just add to this topic, with some info.

Just had this issue with my 208Gti N18 HPFP for the second time now. (car done 160k)
I'm a damper/ shock absorber design engineer and run my own business selling shock absorbers for motorsport use in the UK.

Watch a few videos online then stripped a secondhand one from eBay for £50 to see how it disassembled, then did my own.

The oil inside mine is Silkolene 02 damper oil has the same texture and viscosity as the old oil and as it is designed for high-performance dampers it can withstand the stresses and high pressure seen in this pump so I'm 100% sure that this is the correct oil to use for this pump. (a cheaper alternative is Silkolene 5wt both oils can be found at any motorcycle shop as Fork Oil.) using standard engine oil or gear oil won't last as it's not designed to withstand the stress and shearing properties that are found inside this pump and high-performance racing dampers.

I'm also sure that, the main issue is oil loss. properly leaking past the pressed diaphragm.. (the only place I can think it would be.. All the O-rings seals seemed fine in mine.

Also, the diaphragm works as a chamber for oil expansion due to heat however it's also there to apply pressure to the oil to stop oil cavitation which is why it is important to ensure there is no air in the system as it will cavitate the oil as well and cause the pump to not work properly. Feeling the pressure of the spring, I say it needs to measure at 13-14mm when it gets to 21-22mm there is not enough pressure on the oil, and when it gets hot the oil loses viscosity and will instantly cavitate causing it to not generate enough pressure to push the other pistons down. (hence the odd pressures when looking at the fuel rail data from the car.)

ATM the best way to re-oil the pump is to submerge it all in oil and then pull the diagram right back (give it a few pumps to get the air out.) with a pick and then screw it all together making sure the diaphragm is pulled back when screwing it together. then remove the fuel solenoid and clean the fuel passageways out with brake cleaner. (Make sure you remove as much of the oil as possible and clean the fuel filter found inside the intake fuel pipe.

That is all I have done and it is working perfectly fine again. The diaphragm measures 14mm. the car starts when hot and the erratic fuel pressure when idling or holding a steady throttle has gone.

would say it is best to reoil the pump every year to ensure you don't get wear on the moving parts.

Regards,
Alex

 

Nice! Let your Peugeot and Citroen owners know we have the metal water pipes now also. We don't have those car over here and I know their are a bunch in western Europe.

 

When I got a not-quite-fixed HPFP in my car, I knew it was going bad because I was finding oil -- not engine oil, not gear oil, not any kind of standard car-automotive oil -- on the plastic thermostat housing sitting immediately below the bell housing on the HPFP. I was also finding the same oil on the exterior of the opening at the bottom of the bell housing, so no mystery as to where the oil on the thermostat was coming from. There was no question that the HPFP was leaking in the literal sense, past the diaphragm.

So you're spot on. No question.

Really good post of your details/how-to, and a major thank you for specifying what oil to use. It's a mystery to a lot of people.

 

Hi

Thanks for the info. Im also in South Africa and im looking at rebuilding my girlfriends HPFP. I can't seem to view the content in that link you shared.

 

I too am trying to view this website, but getting "This content is password protected. To view it please enter your password below:" does anybody know how to get a password? Or can somebody save the content of the procedure shown there and share it?
I have spent way more time than I care to admit the past week researching how to rebuild these. I have an N54 but these pumps all work on the same fundamentals. One thing I've found that wasn't listed on this thread is replacing the shaft seal. It seems there might be some discrepancy about its size tho. One guy says it's (size in mm) 22 x 11 x 7 and another says its 22 x 10 x 7. It appears to be a double lip seal based on the sections views floating around, curious if a triple seal would be any improvement. I've bought a used N54 pump and intend to tear it down and see what I can discover. I'm currently trying to track down replacements for the "thermal compensator" as well as a the solenoid valve "fuel control valve." It seems the coil at least on the solenoid is a C22 coil, so it's a start. Also for the thermal compensator, I have some leads but it requires more investigation. I have contacted black stone labs and intend to send them a sample of the oil, it sounds like they can identify the grade and viscosity for sure, but that they "would do their best to identify the oil type" So the hunt continues!

 

Mate the oil isn't the issue. If it was the car wouldn't work at all and have the issue when driving.

I've change that oil properly and vac bleed it aswell. To bleed it, you remove the lightly pressed it diaphragm and fill the pump with 5wt shock oil through there and vac bleed it. Then fill the diaphragm with oil and quickly seat it back in and press the part back in.. Making sure to use a sealant around it.

Been trying to understand this issue and I'm sure its the solenoid valve coils that are deteriating due to the heat. It is put in a place that gets no air to it.. When the car get hot and u turn it off for 5 mins. It will struggle to start for say 30mins to 1h.

But if u open the bonnet for 2mins or poor some water on top of the pump The car will start straight up. So basically somehow you need to find a way of keeping it cool. I was thinking of trying gold tape to reflect heat away from it.

But its annoying that bosch do not sell that valve separately or someone hasn't made an aftermarket one for it. As I'm sure that the issue.

 

No offense, but dead wrong. I went through multiple HPFPs while trying to sort all this out years ago and part of the problem was the HPFP leaking oil right out of the hole in the bottom of the bell housing on the HPFP. Falls straight down onto the thermostat housing. Easy enough to spot once I got to paying close attention.

Over time the seal goes bye bye. As you have mentioned sealing it, it doesn't exactly make sense for the seal to go bad, have the oil leak out, and have such failure NOT have consequences. Over time the lack of oil used in hydraulically pressurizing the fuel causes [measurable] lack of pressurization and loss of that pressurization = car doesn't get fuel in as fast as it needs. But it doesn't fail catastrophically, it's slow death, and that slow death has been reported widely enough that it isn't really hypothetical.

I won't claim that the solenoid has nothing to do with it, but I actually went through the trouble of swapping known-good solenoids into known-dead-or-dying HPFPs. I literally had five of these things in my possession at one point, four on the counter and one in the R56 S. Swapping a good solenoid into a bad HPFP made NO difference on any of the four failed/failing HPFPs (which were all at different levels of failure from 100% not happening to iffy 20-25% of the time). Zero behavioral change, not better, not worse. Literally no difference.

Solenoid-swapping making no difference at all told me three things.

(1) the common failure, across four separate physical HPFPs, wasn't the solenoid.
(2) a good solenoid couldn't resurrect an HPFP that had failed for "whatever the reason" those four had failed (one had only started to fail, but was actively leaking hydraulic oil despite being "new.")
(3) a solenoid failure was possible because they're man-made, and man-made things fail. But without a known-bad solenoid, which I apparently didn't have, differentiating bad-solenoid-cause from leaking-oil-cause was not possible.

I'm sure a bad solenoid would nuke an HPFP but not in the way that is most broadly observed and discussed to death in this thread.

BTW, I noticed the tie of behavior to temperature as well. Never figured it out, but like you, I noticed it.

The HPFP is made by Continental, not Bosch. I don't have my "HPFP museum" any more to see if the solenoid was made by Bosch, but I took a ton of pics back then and one might be way back upthread showing printed numbers and/or other info on it. Maybe. Been literal years since I took or looked at those pics tho.

FWIW / Cheers