I have a 2010 Mini JCW. My issue started when my car wouldn't start in the morning, the fuel gauge is showing 4 bars. First i check for spark, all good, replaced the plugs too. I check the fuel filter and replaced it, still wouldn't start. I checked the LPFP realized no voltage when ignition on, checked the white and blue cable from the LPFP to the JBE for continuity, all good. Took the LPFP out and test it with 12v battery the fuel flows. Decided to take apart the JBE and replaced the NEC relay, put everything back together still no voltage on ignition on, only when i crank the engine it shows 10.4v. I refill the gas about 10 liters. the car would fire up but stumble first. took it for a drive (still 4 bars on the gauge), on hard acceleration the car stumbles. Decided to fill up the tank fully, the car ran beautifully but still hard to start, seems the fuel is not holding up in the fuel line. I decided to empty the tank again to check the fuel gauge is showing the right value, refill just 15 liters (about 3 bars on the gauge) it stumbles and dies again.

The car is hard to start even when left off for just 1 hr, runs beautifully when the tank have at least 5 bars, but below that it would stumble and die. What seems to be the problem?

 

The DME controls the relay and will only send power to the fuel pump when the engine is starting/running. So what you've described is normal behavior.
I would suggest doing a fuel pressure test on the LPFP. Just because it ran when you applied power doesn't mean it's performing under load.

 

Thanks for the input. How should I test the fuel pressure on the LPFP? should put a t join and gauge in between the LPFP and HPFP? what is proper the pressure for the LPFP? and it seem the hard starting issues is because the fuel is not holding up in the fuel line, does the LPFP in charge of holding the fuel to the HPFP? Is there like a one way valve to hold the fuel?

 

Basically, yes. Mini has a special tool with a T fitting that goes into the quick disconnect fitting where the fuel line comes into the engine bay (underneath). You'll need to find a away to power up the pump without the engine running. It should be 5.0bar (72-73psi).

 

Did you figure out the problem? I'm having the same issue.

 

Had same problem. New HPFP fixed it immediately. Expensive part, but just buy a rebuilt one.

Good luck,

Rick

 

The problem you are describing sound like an Evap issue in the Carbon Canister. Where if you refuel to full, it will start/stumble/stall out

 

I replaced HPFP, coils, spark plugs, LPFP, fuel filter. Still same issue. I'm going with a new passenger side fuel sending unit after I check the lines and the siphon on the current sending unit. The stuttering and stalling only happens at 1/4 tank of fuel. No codes until 1/4 left and it starts stuttering and stalling and then I get the P0301,P0303,P0300, P2096.

 

Fault Code P0300, P0301, P0303; these are cylinder Related Code, either low Spark, not enough fuel or the piston has an imperfection preventing full functional cycle.

best guess after everything you did would be a faulty wire or poor connection to the coil wiring. Swap the coils, make sure they are in snuggly and see if you get the same error. Take cylinder 1 coil and swap with cylinder 2 coil, get a reading. Then swap cylinder 1 coil and swap with cylinder 3 coil, get a reading, Etc… compare the readings and if they are the same in every instance then it’s the ignition system (power going to the coils) and the coils are fine.


Fault Code P2096; this is saying you have an exhaust leak post 1st o2 sensor, but pre 2nd o2 sensor and it can’t get a good read.

at best this is just something that needs tightening up (the o2 sensor, the vband, bad gasket ?!?! …), worst you need a new o2 sensor.

 

I have swapped coils and plugs. I would be inclined to agree with you if those issues were consistent but they are not and only happens when the engine is at 1/4 tank of gas. Which is caused by the engine not receiving enough fuel. The fuel gauges are correct when compared to the fuel remaining in the tank and that's why I believe it's the sending unit. Hopefully I have some time this weekend to get it fixed.

 

P2096 indicates fuel starvation.

 

Oh, sweet Jesus, post a resolution! I fixed the .... all is good.

I sent it to the scrap yard and bought a Ford.

Give an update!!!!!!!

 

Indeed, the problem can be both with the ignition coils and with the fuel. I recommend checking everything carefully, just don't forget about the oil, maybe the problem is its quality, you can try to change the oil, here find Best Oil for 6.7 Cummins Diesel https://casperoilchange.com/oil-for-...iesel-engines/, pay attention to quality manufacturers