Hi Everyone, longtime NAM lurker and have been coming to the boards for small issues I've been able to resolve easily that are common for a R56. However, this time I need some help and need to go into a bit of depth on what is going on with my Mini. I'm hoping someone can give me some insight. I have a 2010 MCS with 79K mi that has been having stalling issues for some time and after having the car serviced by my regular mechanic, it was resolved. However, the same occurred again shortly afterwards and it has evolved into an issue I can't seem to figure out.

The car started with intermittent stalls on the road and sometimes it wouldn't start up after a brief stop. I would have to wait a few minutes before the car would start again. When it didn't start, I had it towed to my regular shop to diagnose the issue. The techs found the car would start and idle for 5 to10 minutes and then stall. It would then not start until 10 more minutes passed and it would stall again after about 5 minutes at idle. No engine faults, except for the thermostat which is a P0597 (control circuit/open) and I plan to replace this myself. They checked the fuel pressure and it was normal while idling and when it stalled it dropped below spec. They suspected the HPFP was the cause and they replaced it, but it stalled again after 5 minutes with the new one in place. The old one was placed back in and with the car on the lift, disconnected the low pressure lines to get readings and confirmed the LPFP was working in the tank. Readings were normal and after they reconnected the fuel lines the car stopped stalling. Oddly, disconnecting the fuel lines on the lift seemed to have fixed the problem.

A few weeks pass and then the issue started again. I started seeing P2188 code faults, system too rich at idle. I figured this was due to the thermostat and it's under extended warranty from Mini USA, but couldn't get it replaced at the dealer until the code reappeared as it was cleared while stalling issues were addressed by my regular shop previously. They informed me of the extended warranty as well. Shop checked spark plugs, smoke tested intake system and found no leaks, valve cover has been replaced already, walnut shell blasting was done back in 2013 (49K mi ago), the throttle body was cleaned out just in case, and no other issues were found. The car did not stall again while under their care and I picked it up. All was well until it stalled again a few weeks later and this time the smell of gas was pretty evident. Seemed to be in the engine area or under the car. I couldn't tell for sure since it was pretty strong. I had the car towed home once again and it fired up once off the flat bed and I moved it into my garage. It fired up once since parked in the garage and stalled after a few minutes and has not started again.

I decided to troubleshoot shoot it myself. I replaced the fuel filter since I believed it may be an underlying fuel issue and wanted to start with the basics. It was black and dirty along with the fuel in the fuel filter housing. This was not a hard task to replace, but now I find that fuel will not get into the line to the engine. There was fuel in the line when I initially disconnected it. I don't hear the lower fuel pump when I put the key in the 2 position, but I can hear a hum in the engine as I try to get fuel back to it. I have disconnected the fuel line from the top of the fuel filter housing and find it does not have any fuel in it and only once had a bit of pressure. I have cranked it several times and have let the fuel prime as I have found in other posts here and on other sites. I took the filter housing apart once more to make sure the gaskets were seated properly and reinstalled it. Added more fuel to the tank also. Tried to start it and no success yet. I'm thinking it may be a failing LPFP, but then I read that it can stop working because of other reasons like a fuse or relay reset. Not sure what I should do next. Any advice is of course immensely appreciated.

 

You might want to confirm if the low pressure fuel pump is working by direct connecting the power to pump. If it is working then you have to determine if the JBE supply the voltage to Low Pressure Fuel Pump when "key in". If no power supply, then the possibility of the relay (K96) went south and you have to replace the JBE.

Hope this help.

 

Thanks for the info. I've been reading up on the JBE and will be ordering a DVOM so I can do some testing at the pump and connector. I will direct connect the pump to power and I have to figure out how that's done also. I checked out the fuse in case it was blown and turns out I don't have a 20A fuse in F43 which is odd. Online I found this is the fuse box relay location for the LPFP. Is it possible for the car to run without this fuse in place? I checked F37 and F46 since they are mentioned also as likely culprits and those are fine.

 

You should check you fuse box cover to confirm the fuse for low pressure fuel pump. In my case it is F46 and F43 is empty. My is 2009 fJCW. UK spec

Attached is my JBE for your reference.

 

Thanks again. Looks like mine is in fact F46 also.

 

Update on the status of the car: I've been doing research on my issue and thus far I ended up replacing the thermostat and the water pipe myself. Not too bad a job except for the manifold being in the way. I also direct connected the LPFP to battery power and confirmed the motor is working within the pump. I placed the LPFP back in the tank and I need to check on the power coming in to the fuel pump with "key in" as I now suspect it is the JBE/relay or something along the way. I tried checking the voltage at the connection to the pump, but I was getting voltage readings I don't quite understand. I'm starting to suspect it's an electrical issue, either the JBE or some exposed or corroded wire since the LPFP works when directly connected to power. How do I confirm or test the JBE is supplying the right voltage or not?

 

Any word on the cause. I have the same problem and I have replaced lpfp and hpfp and still have the problem. When I activate the tank vent solenoid using my diagnostic tool, the engine will restart, but run poorly until I deactivate it, then it dies. Since I can activate the solenoid, I am assuming that it is good.

 

No word on the cause yet, I'm trying to work on it as fast as I can in my spare time. The readings I got from the LPFP terminals were not similar to what I read about in doing testing (it should read about 12V and I'm getting between 120-150V so not sure what that means either). I'm sure I'm doing it correctly. Per other posts I've researched, the voltage at the pump should be around battery voltage and it is not.

I found this on post NAM and it leads me to believe it may be the JBE or some other electrical issue as I noticed the battery is draining pretty quickly after a recharge.

 

So I am pretty sure the problem in mine is the lpfp relay located on the JBE mainboard. I am working on installing a separate relay for the lpfp and just not using the one on the board. As far as your voltages, either you have the multimeter set on the wrong or you are reading millivolts and not volts. You should have the multimeter set to 100 or 10 VDC. There is no way you should be getting 120V from anywhere in a Mini.

 

After months of trying to get to the root of the cause in my free time, finally confirmed it was in fact the JBE (LPFP relay gone bad). Unfortunately, I was no longer able to work on the problem in my spare time/days off so I ended up taking it back to my mechanic where a temp JBE was installed for testing and the car fired up just fine. I know I needed to replace it with a JBE unit with the same model number, but I couldn't wait any longer to find one on Ebay or used etc. so I had them do the swap for me with a new one. I hope this helps anyone with similar stalling as I had a hard time getting to the bottom of it. And, to note, this is very common apparently in Coopers with a sunroof due to water damage from leaky sunroofs and/or poor draining. Just an FYI. My MCS does not have a sunroof so the relay just gave out in my case.