I am having trouble with our 2011 R55 Clubman S. The car stalled and refused to restart. We read the code and it showed that the fuel rail pressure was low. I investigated this online and the resolution was to replace the High Pressure Fuel Pump. I bought a rebuilt unit from a fellow in Canada and installed it but we have the same issue. The car will start up cold and drive maybe 2 miles and then begin sputtering and then quit. Read the codes and it’s the same thing; low pressure at the fuel rail. The car has now sat a few days and it stare\ted right up today and ran for about 10 minutes in the driveway and then sputtered and stalled.

I have a Foxwell code reader that allows me to see the fuel rail pressure and when it’s running right, the fuel pressure is above 7 bar and will go higher if the revs go up. When it begins sputtering the pressure will drop dramatically and it will stall when the pressure gets to about 1 bar. See picture below:




The scanner has a logging/graphing option and as you can see the pressure is .12 MPa which = 1.2 bar

The low pressure fuel pump seems to be working fine as it shows 5 bar all the time, even when the engine is stalling, no drops in pressure at all see pic:



500 Kpa = 5 bar, which is normal for the low pressure pump.

Im at a loss as to what to do next. HPFP is rebuilt and the LPFP seems to be working fine. The fuel filter is new. What to look at next?

Jon

 

Any kind of warranty on the HPFP? I wouldn’t be surprised if you received a dud.

 

Certainly the rebuilt HPFP is suspect.

It is understandable to blame the HPFP and I'm sure in some cases the HPFP is bad but the low pressure fuel pump has to work right 100% of the time to keep the HPFP supplied with a sufficient quantity of fuel at a proper pressure. My limited 1st hand experience with bad low pressure fuel pumps is they can work just fine then they don't. But then upon a restart they work fine again. Until they act up again.

My opinion is you need to view the low pressure fuel pressure concurrent with viewing the high pressure fuel pressure to verify when the HPFP pressure drops the low pressure fuel pressure is still to spec.

 

I have only experienced a bad HPFP once ( my friends JCW Clubman ). His symptoms were the opposite of yours - it was hard starting, but once started it was fine ( could be the early stages of pump failure ). This was a new pump from ECS. He replaced it with a take out from another clubman and has been fine since.

Fuel delivery on these things are frustrating ! I would explore the low pressure guy too - perhaps replace that and see what

Here is another post on the subject

https://www.northamericanmotoring.co...-2011-n18.html

 

The rebuild has a 2 year warranty, so that may be an option.

I did order the LPFP and have it in hand, I’m just not getting any codes for it and the pressure seems to be spot on at 5 bar. I really hate to just be throwing parts at it.

What does the electrical wire do that plugs into it do? The HPFP is a mechanical device powered direct from the camshaft and the fuel pressure sensor is on the fuel rail.

The depth of the spring plate on the old pump was 27mm and the rebuilt is 15mm. This seems to be a diagnosis for a bad pump and 15 is supposed to be “good”.

thanks for the replies and help!

jon

 

Regarding your question about the depth of the spring plate differences that's a question for the guy in Canada...

 

If you have the low pressure pump in hand, might as well install it and see what happens.

 

Happened the same with me. The car started and no Rail fuel pressure, but in the other day it starts without any issue.
Maybe still air in the system .

 

My guess is air or something, i remember when I did my low pressure fuel pump or when I disconnected the fuel line on the HPFP, it took a bunch of starts to get it going again.

So after you done some work it takes a bunch of times to start. I was even thinking of locking and unlocking the door to get the LPFP to prime, it will makes a whine noise for like 3-4 seconds.

Think you got some air in it.

 

Thanks for suggesting the things to check. I will install the new LPFP since I have it in hand.


here is a video I took while the engine was stalling last week. The upload to YouTube makes the quality pretty bad. What you see is the LPFP pressure at 500 kPa (5bar) steady as a rock. In the background you can see the tach, with the revs fluttering and dropping as the engine begins to stall. You can see the check engine/limp home, 1/2 check engine light come on too.


I have also looked at some electrical issues, that come up when searching. Particularly the broken solder for the LPFP relay in the fuse box.

Jon

 

Is that the set point, or the feedback? I didn't think these cars had a separate low pressure sensor. As far as I knew, the only fuel pressure sensor was the one in the fuel rail...

If indeed your low pressure fuel supply is rock steady, then for sure the high pressure pump is to blame.

 

This is the golden nugget of info I needed! I assumed, that if the scan tool was showing a value, it was showing actual pressure.I’m not super familiar with the Mini and it’s why I came here for advice. I have just searched this and have discovered that there is no LPFP pressure sensor. The only way to check the LPFP is to use an inline gauge. Here is some info from Pelican Parts:



I will replace the fuel pump tomorrow and report back. Thanks for your comments and help!

 

Problem Solved!

it’s wasn’t the LPFP after all, but the LPFP relay in the fuse box. The solder on 1 leg of the relay connection looks like it gets hot and the solder cracks around the pin. When I got to the car this afternoon and started it up, it ran for 2 minutes before it starved of fuel. I got out the volt meter and hooked it up to the input leads that go to the pump. It took about 10 minutes before it would start again and I was reading the volt meter when the voltage began to drop. Slowly at first then boom, 10 volts and the pump stops, then right down to 1 volt. This is what led me to the relay in the fuse box. Here are some pics to show you what I found.

This first pic is of the board that the relay is mounted to. You can see the dark square from heat in the center upper right.


this one shows it close up. You see the solder cracked on the pin and, to me it looks like it was arcing in the crack.



a close up of the pin and the broken, arced solder joint.



you can see here that I have resoldered this pin with a big blob of solder.


The engine ran for 50 minutes before I drove it home. Everything is working normal.

 

NICE - it was the HPFP, just not the pumps problem, but it's electrical supply !

 

Great that you found that!

 

Day 3 after repair, and the Mini is running sweet.

For folks searching for fuel pressure info, here is what you should do to save a lot of time and potentially money.

Regardless of the code you are reading, start with the Low Pressure Fuel Pump. Check for voltage at the plug of the LPFP first. This will help you eliminate the bad relay solder issue. The relay issue is also intermittent so be patient and run the engine long enough to see if the voltage goes down to below 10 volts. Just poke your VM probes thru the insulation to constantly measure voltage while the car is running. Pulling the fuse box is quite simple, so don’t fear making the repair like I did.

change the fuel filter, easy to do and small money.

monitor the High Pressure Fuel Pump via a scan tool that shows live data. If you think the HPFP might be bad, pull it off (maybe 20 minutes) and measure the accumulator spring. 13-15mm is good, 27mm is bad. There are many threads online showing this.