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I have a 2012 R56. Th eoriginal HPFP was replaced in 20149 under the Mini reacall. In October of 2024 IO had that pump so signs of failing (fuel rail pressure drop and going into limp mode). I replacved the pump with a new "OE" suplier pump and all was good. After about 1000 miles I had the same issue. I sent the pump back to and had it swapped for a new one. Again all is gfodd until about 1000 mile and then the sympotoms returned. Sent that one back and replace with a genuine Mini unit. All seems to be good but while monitoring the fuel rail pressure I saw the preessure momentarily drop to 0 and then return to ~1200 psi (going down the freeway). Ther pressure dropped a secoond time and this time the car went into limp home mode. Pulled to the side of the road, wiated about 5 minutes reset the code and all seems to be good agian. Any idea what might be casuing this? This is my daily driver and having it die on the freway at 70mph is no fun.
Bad pressure sensor on the rail? The low pressure fuel pump in the tank cutting out? Usually the low pressure when it goes you will not hear it prime in the fuel tank right when you unlock the car to start it up.
Did you scan any codes? My guess is a faulty fuel rail sensor.
Rail sensor has been replaced. I have a new tank pump but the tank is currently full so I am trying to run oit down so I can change it. Pressure at the rial is reading 72psi before I try and start the car.
On the way to work kthis morning the mini through a code and died. I pulled over to the side of the freeway and reseet the code to restart the engine ( at the time I was monitoring pressure from the tank pump and it showed a consistant 72.5psi). Car started and I returned to driving to work. Started to monitor the HP fuel system and the pressure was consitantly low ( see screen shots below, the first image is as I sat a stop light, the second is travelling down th eroad). I also noted that when I had to stop at a stop light the rail presure woudl continue to climb but never reah the setpoint values. Any ideas of wht could be wroong? I did have an instance about 5 minutes before the checkk engine light where the pressssure fromthe tank momentarily dropped to zero and tehn returned.
I would change that rear fuel pump, something is starving the fuel and its dropping in pressure. Make sure when you change it the seal at the top of the fuel pump is sealed on both sides, we see the seal can leak and cause issues. Same with the fuel filter seal.
It's not that complex. You have a volume supply pump from the tank, a pressure sensor in the rail, and a high pressure pump. You've replaced the high pressure pump numerous times and continue to have the same issue, the problem lies elsewhere. If you actually did burn up 4 high pressure pumps, I'd theorize that the low pressure pump is not providing proper volume, starving the HPFP and causing premature failure (run dry).
The in tank pump isn't an exceedingly difficult repair, but it's highly recommended that you replace the fuel filter after you change the pump.
I have a new tank pump ready to go, just need to get the fule level down (the tank is full). I'll keep everybody posted. I think it is strange that if I look at the data form the tank pump it shows a consitant pressure. Is this pressure not read real time?
I have a new tank pump ready to go, just need to get the fule level down (the tank is full). I'll keep everybody posted. I think it is strange that if I look at the data form the tank pump it shows a consitant pressure. Is this pressure not read real time?
I can't say for certain about how the pressure is measured. My understanding of the electric fuel pump is that it is a go/no go item - you're not going to get 'lower' pressure, you'll just get no fuel. Just an assumption though, from experience with electrical pumps/motors over time in various applications. It's a DC system, so the supply voltage is constant and the pump will then operate at the same velocity dependent on that voltage. When it's operating, it supplies a specific volume and pressure; when it stops, you get nothing. Assuming there's a check valve in the system, you will see pressure in the system, but pressure isn't the same as volume.
After 807 miles on the new HPFP car died on the on ramp to the freeway ( the previous 2 replacement pump also had this issue between 800 and 1000 miles after install).. Waited about 10 minutes the car fired back up and I drove the 30 miles home no problems. This issue seems to happen more when the engine is cold, or I have only driven a few miles ( like just after getting on the freeway) though I have had it happen at about 30 miles). As stated before I have replaced the tank pump, fuel rail sensor and the HPFP and still get this issue. Any ideas?
Driving me nuts. I have looked at all of the connectors and they are good. Going to Sonoma next week for a lemons race in our other R56. I will look at this car after that. Thanks for the reply
After much hair pulling this has finally been solved. The car finally quit and would not restart. Further trouble shooting led me to the low pressure pump not working and the real problem turned out to be a cold solder joint on the fuel pump relay. Separating the boards and reflowing the solder joint has fixed the issue. I have ordered new relay and will replace it when it comes in.
