How much fuel pressure do you get at the fuel rail on idle? I’m under the impression that it should be in the 700psi range but mine reads 1100psi at idle so I have a few questions.

Could this be caused by a failed frp sensor?

Could this be a symptom of another issue and the ecu is increasing frp to compensate?

It goes up to about 1500psi at 2500-3000 rpm when revving under no load.

 

Also reading the pressure on my scanner shows 116psi with the engine off key on.

Anyone?

 

I just happened to scan the fuel rail pressure on my son's MCS today (trying out BlueDriver OBDII app) and it reads 705 psi (about 48 bar) - however, searching PelicanParts website regarding fuel pump shows setpoint as 75.9 bar (1100 psi) on their 'professional' scanner. So I'm just as confused as you are...will search to find spec with tolerance.

 

I was able to get some readings on another r56 that was at the dealership for an oil leak but otherwise running well and it showed 750 psi on my scanner. The dealer is going to do some tests over this next week so I’ll post back when I hear results.
Thanks Sleepy!

 

I should point out that the earlier measurements on our Gray MCS is from a brand new HPFP on a rebuilt head. I just measured the fuel rail pressure on our other '07 MCS as part of a root cause analysis for hard start issue (either HPFP or fuel tank pump) and obtained nearly identical results. Upon further searching, my results concurs with specification provided by MiniMania, albeit on the low side:

"The HPFP is driven by a mechanical connection to the intake camshaft with a maximum fuel delivery pressure of 120 bar (1,740 psi) at full load. Idle is about 50 bar (725 psi)." Here is the link: http://new.minimania.com/Mini_Cooper...lication_Guide

Hope this helps.

 

I checked mine this morning variance on idle 780 to 975psi and then way up there at driving.
Ben

 

I know this is an old thread, but I wanted to put out there. There is very little info available about this. But apparently MINI changed the fuel rail pressure on the N18 with an ECU update.
From what I can tell, they bumped it from 750 psi at idle to 1100 psi at idle.
this had me very confused trying to diagnose my HPFP because I was reading too high of pressure. But now with this knowledge, I’m sure the HPFP is toast.

 

Did you ever figure out what was causing it? My 09 R56 is sometimes (more often than not) reading 1100 psi as well. Idle is rough and jumpy. It's like it's surging.

 

Old thread, but I have an issue with fuel pressure as well so did not want to create a new thread.
Mini R56 N18
Sometime I get check engine light in a dash and it appears, when revs are below 2k rpm. If I rev higher, check engine light dissapears and then appears again, when rpm drops below 2k.

I checked live parameters with OBD scanner and noticed that on idle, fuel pressure is normally around 1100psi. But sometimes it starts to fluctuate and when it drops below 1000psi, engine light is ON. But it drops only for a milisecond and when goes back above 1000psi, check engine light goes away.

Anyone have ideas what might cause this fuel pressure fluctuation?
As I heard, N18 HPFP do not fail, so I would like to start diagnosis somewhere else, than changing HPFP.

EDIT:
I forgot to mention, here is what fault codes I got with this:
P0001
P0003

Also, I have some electrical problems with alternator sometimes charging, sometimes not, so wondering if it can be related...
Alternator changed twice and it's definitely working well, so problem is somewhere in wiring or computer.

 

The Bosch pumps are better than the Continental pumps which very much so do fail on the N18. If your car is 2013, I believe, or later you will have the Bosch.

 

Yes, the car is late 2013 and I think has the latest version of HPFP.

 

P0001 is the OBD-II generic code describing an issue with the circuit which runs from your engine computer (ECM) to your fuel pressure regulator on your fuel injection rail on your engine. The ECM regulates your fuel pressure from your fuel pump going to your engine through this circuit.

P0003 is a generic OBD-II code indicating an issue with the engine control module (ECM) reading signals from your fuel pressure regulator on your fuel injection rail mounted to your engine.

Think I "see" a pattern...

The electrical problems you are having the alternator could very well be related. I don't necessarily think the alternator is bad but as you mentioned it does cast suspicion on the wiring circuit of the computer.