I think I'm just out of options now. I don't have a way of checking the fuel pressure out of the hpfp so I might just get a mini specialist to look at this now. Unless you have any ideas that are free or cheap?

 

Are you able to clear fault code A10A?

I wonder if your inability to read the fuel rail pressure suggests a bad fuel rail sensor?

One way to diagnose whether an engine no-start issue is caused by a fuel delivery problem is to spray starting fluid into the air intake (air tube upstream of throttle body but downstream of air filter) while cranking the engine. If the engine starts temporarily with starting fluid, then you know your no-start issue is related to fuel delivery.

 

Hi, I also had a similar problem, my mini stopped starting one day, if I started the starter motor but it would not turn on, at that time I did not have many tools but investigating I started the same as you, looking at the fuel supply, but before changing or checking the low pressure pump, I found a lot of information about an internal relay in the JBE fuse box that controls this pump, which usually becomes unsoldered. I leave you a video, in my case this was not the error since it was the fuel pump that was broken, you can check very easily if it is the low pressure pump, just disconnect the gasoline hose that goes to the high pressure pump and put a disposable soda bottle on it and start the car, if it is empty your problem is in the low pressure pump or in the fuse box, I hope this helps you.

 

So I sent the car off to a mini specialist who found that an o ring was missing in the fuel filter assembly so it couldn't build pressure. He fitted an o ring and the car started easily.

I'll have a more detailed chat with him when I pick the car up on Monday but this is very frustrating because the assembly was brand new from BMW so I didn't suspect it could be faulty. That's really bad quality control.

 

Oops double post

 

You previously posted a reading of 680 kPa (98.6 PSI) from the fuel low pressure sensor. Normal pressure from the LPFP is ~72 PSI, suggesting that your LPFP was producing higher than normal fuel pressure rather than lower than normal fuel pressure. These observations seem inconsistent with a LPFP that can't build pressure. Did the Bimmerlink reading from the fuel low pressure sensor change after the new O-ring was installed?

With that said, I'm really happy your Mini is now running again.

 

Yes that's a good point.
I'm skeptical and will query it again when I collect the car on Monday but if that's what he's telling me there's not much I can do about it. I'll check the reading again when I can.

At least he's not telling me an expensive part needed replacing. I haven't been sent the bill yet so let's hope there wasn't much time involved to resolve the issue. Parts cost should obviously be minimal.

At this point I'm just happy it's working.

 

 

Bentley has a great video here on the testing the line pressure and how its acts.