Hey there,

My R55 Clubman Cooper S with an N14 engine started to act up recently. At Startup the car will sometimes stall, sometimes nearly stall and shake violently for a few seconds until it starts idling. Then again, it will sometimes just start right up.
Idle itself is kind of rough with revs fluctuating up and down. The behaviour at startup and idle is the exact same, no matter the engine being warm or cold.
The check engine light comes on sporadically after idling for a bit. As of right now that only happened with a warm engine. It starts to run extremly rough and loses power after the light comes on.
The light is gone immediately after restarting the engine and I can't find any record of saved error codes with my OBD II scanner afterwards.

A few days ago I managed to get a check engine light while having my OBD tool connected for live data. The Error code was P3091 followed up by P2880, both of which are codes pointing towards the high pressure fuel pump. Live data indicated this being true.

Measured fuel rail pressure before the check engine light came on:
Idle: about 4800 kpa (696 psi)
Lowest: about 4500 kpa (653 psi)
Highest: about 13000 kpa (1885 psi)
Idle rpm: 800-900, feeling rough sometimes

After the check engine light came on:
Idle: only 700-800 kpa (100-116 psi)!
Lowest: 650 kpa!!! (94 psi)
Idle rpm: a drop to about 550 at first, afterwards 650-850, fluctuating wildly.

Immediately after restarting the engine, error codes were gone and the pump went back up to the 4800kpa I saw at idle while driving normally.
Even while the engine had wonky fuel pressure, the OBD tool couldn't detect any missfire. After about half an hour of driving (before the check engine light came on), the software recorded three missfires on cylinder 4, two on cylinder 1 and only one on cylinder 2. That's it. It didn't change after the light came on.

I already looked at a few threads regarding the High pressure fuel pump in multiple forums and looked through a load of YT-Videos. I found the thread here discussing repair of the HPFP particularly interesting. (N14/N18 High Pressure Fuel Pump teardown and refresh - Page 12 - North American Motoring)

I would like to repair my fuel pump this way and share the process as well as it's results with you!

Only thing is: Before I start ripping it apart, I would like to know if the HPFP is really to blame here. Do you think my HPFP is broken? I don't feel like I'm down on power while driving normally. The drop in fuel pressure as well as the rough behaviour of the engine will only show up at idle and startup. Everything feels perfectly fine once above 1500-2000 rpm. The check engine light will also only come on at idle. Ideas?

Thank you for your help.

I'm sorry if there are grammatical errors, since English is not my first language.

If there are questions remaining, please ask. I'm more than happy to answer them. ; )

Greetings

 

Oh: I forgot to tell you: Timing chain is new, the Spark Plugs and a broken coil pack have been exchanged as well.

 

I would check the low pressure fuel pump first. If it's malfunctioning then it can starve the HPFP.
If I recall correctly it should make 70-75 psi.

 

Thank you for answering! I just ordered a new fuel filter to start of.
Weirdly today the car ran completely fine the whole day. Only idle right after startup was a little rough 2 times, but far less than before and only twice. Both starts were more or less coldstarts.

So the problem doesn't seem to be gone, but it's better?

My Mini is messing with me. XD

It ran rough most of the time for two weeks, now it doesn't do it as often?

 

Those numbers look low for the HPFP. Does it struggle to start after sitting all night? If you have the ability to monitor the fuel rail pressure real-time, just watch it. If it dips below 600 a lot, then it's probably going out. They gradually go out. If it struggles to start in the mornings, my bet is on the HPFP.
Don't waste your time with trying to rebuild it yourself. I've had really good luck with the reman from ECS. I've put them in a bunch of N14's and they worked like a champ. Don't waste your time on the ebay pumps either, complete waste of time and money.

Here is the ECS HPFP. It's a better option than a brand new pump from Mini for $1K+

 

Thank you.

Today the car ran like **** again. The fuel filter arrived, going to put it in tomorrow.

I'm from Germany, therefore I can't really buy the pump from ecs. Thank you for your suggestion though. Maybe you know some european company selling aftermarket high quality parts? I thought about pulling the trigger on this one: https://m.autodoc.de/metzger/15819768

Any comments/opinions or ideas?

Thanks a lot for your answer.

Edit: Below 600? You mean 600psi, right?

 

Hey, just found this:

https://m.autodoc.de/meat-doria/19351439

Isn't that like a fuel pump repair kit? Couldn't I repair my old one with this?

 

Second what mrbean offered. Bad behavior then good behavior is not normal symptoms for a bad HPFP.

 

Hey guys,

As I don't need my car this weekend, I took out my HPFP to take a look at it.



It seems to be leaking badly. I measured the depth of the thermal chamber: It's at roughly 28mm of depth.

So it seems to be done. HPFP is most definetely the culprit.

​​​​​​I'm either gonna buy a new one or try to repair this one. I'd like to repair it, but since it seems to be leaking like crazy, I'm not sure if I can.

Anyways. Thank you for helping with diagnosis!

Do you think I will be able to restore this one or should I just buy a new one? The pump has 126.000 km (roughly 80.000 miles) on it.


Greetings and thank you!

Edit: Just noticed: That was engine oil and me being stupid,
not the Pump leaking.

I'm gonna try to repair it.

 

Hi,

Update: I exchanged my fuel filter and tried to repair my HPFP by taking it apart, cleaning it and filling it back up with new oil.

What I did:

- Take it out of the car

- Take out the 3 screws holding the head in place.

- Open it up. I used a bolt and two cable ties to get better leverage on the head of the pump:


After taking the head of, I was greeted with this:



Oil was fairly clean. Only a little bit of debris inside.

I then took out the cylinders and springs out of the two shafts they go into. I forgot to make photos. I was too concentrated on working on it. : /
Anyways, I took them out, then modified a 17mm nut to fit the shafts so I could take them out. I took them out, sadly one of them got a little damaged doing that.

Anyways. I cleaned everything and put it back together with the pump submerged in new oil to avoid any air trapment. Every step of putting it back together was done in an oil bath. I also turned all the parts around in the oil a bit to leak air bubbles outside. As for which oil I used: I used this one:

It's fully synthetic 75w90 gear oil, which my neighbour had excess of after doing a gearoil change on his Skoda some time ago. That and the similar viscosity to oils known to work well with the pump motivated me to use it.

After taking the pump out of it's oil bath, I cleaned the petrol pathways and the solenoid so the injectors wouldn't get any gear oil running through them.

After I was done the pump looked just like this again:


I'm really sorry that I forgot to take pictures. I'm kind of annoyed myself cause I would have liked to have them.

Anyways. The pump measures 16mm inside of the thermal chamber now and as far as I can tell seems to work. Pressure values are slightly higher than before, but I'm yet to test it fully. Car runs fine at idle and I'm gonna go for a test drive in a few hours. I'm gonna get back to you later with the results!

Thank you!

 

Well, I hope what you did fixes the problem but I can't believe just a bit of cleaning and fresh oil -- and *gear* oil at that -- will do the trick.

If the untoward behavior reappears be prepared to check the low pressure fuel pump fuel pressure to see if it is in spec.

 

Hey guys,

as of right now the HPFP seems to be working fine. I took the car on a roadtrip of around 3000km with no issues regarding the pump. The car still seems to have some slight problems with rough running in general though. I pressure tested all my cylinders, they seem to be a bit low in compression, but it's consistent. Cylinder 3 has a black spark plug though. So it seems to me that No.3 is the misfiring cylinder. No problems with HPFP Codes as of rn though. So that seems to have worked.

I'll open a new thread regarding injectors. See you guys there. ; )

Later and thx again to everyone willing to help. ; )

 

Pump held up quite good for just refilling it. The pump worked just fine again for another 10k Kilometers ( should be about 6000 miles). I was on the road quite a lot these past few months and got my car up from 123k to 132k km on the dash. I visited a friend in Switzerland and in another part of germany with my car, when visiting places there, we drove my car as well, and in the end it all added up to roughly 10000 km. About 1000 km ago, the car started to act up again at startup. About 50-100km ago, it actually started loosing power in the lower rev range and nearly stalling at idle. That followed by a check engine code regarding "lean mixture" and a "high pressure fuel system fault". I took the pump out, and sure enough: It lost oil again.
So:

You were right. Calling this a permanent fix is a stretch by far. But I'm pretty damn sure now, that by replacing the seals, you can get a pump to work just like a new one for just as long.
The pump stops working because of oil loss. I sadly didn't really have the time and nerve to deal with my old pump rn, so I bought a new one from Citroën for roughly 700 bucks.
Other than some problems loosening my low pressure fuel line this time around, it went down smoothly. Just as smooth as my engine is idling again now.

Again: Thank you to everybody for your answers in this thread! I'm really happy and thankful to have found such a friendly and eager-to-help forum regarding my car!


In the end, I would like to link the thread regarding my problem with the low pressure fuel hose: Snapped HPFP fuel hose clip!! - North American Motoring

Probably worth looking, if you want to change your HPFP. I think I actually made a valuable discovery regarding the mechanism of the connector. Could save quite some people a lot of trouble and headache when loosening that thing.

Thanks again,

Greetings from Germany.