I purchased a 2009 Mini cooper S (N14) about 6 months ago. The car was apart. Previous owner had followed the 15k oil change recommendation and fell victim to the lose timing chain / drop a valve issue at 69k miles. He intended to rebuild the engine, then changed his mind half way through....so I bought it with the engine out of the car......then I rebuilt the engine and got everything running again.

The car ran 'ok' for the last 5 months.Had good power and boost, but sometimes, on start up, it would run really rough, turn on the check engine light. Most of the time, I could turn the car off and it would be fine as soon as I started it up again.
.....until now.

The car runs really rough on first start then will stall.
I have to put the pedal wide open to get it to start and it runs rough.
After the engine gets some heat, the idle will smooth out and it will run well enough to drive.
If i drive it, the car won't build any boost....so I'm assuming I'm stuck in limp home mode.

I checked codes with a cheap scanner:
P0001 Fuel volume regulator control circuit / open
P0300 Random misfire
P0301 Cyl 1 misfire detected, P0302 Cyl 2 misfire detected, P0303 Cyl 3 misfire detected, P0304 Cyl 4 misfire detected

I tried to read the fuel rail pressure on my cheap scanner, but it doesn't give me that option.
I have Rheingold / ISTA but wasn't able to get it to recognize this car for some reason (maybe that a topic for a different thread).
I went to the HPFP and ohmed out the fuel volume control valve on the HPFP: 2.8 Ohms
I Ohmed out the 2 wires that connect to the HPFP fuel volume solenoid. I had 0 Ohms between the connector at the HPFP and the connector at the DME connector for both wires.
With these readings, I'm not sure why I'm getting an open circuit fault.

My question:
What's wrong? What's my next step?

The signs seem to be pointing to a HPFP.....
.....but why am I getting an open circuit fault when I appear to have connectivity in the wires and resistance in the volume control valve?

Any help is appreciated.

 

All of your symptoms would lead me to believe HPFP… Is the in-tank pump still working ok? What about the tank filter?

If the car is otherwise in great condition, and runs great otherwise, I would invest in a new OEM HPFP and see what it gets you.

 

I haven't replaced the fuel filter yet, but I ordered one last night.

Does a P001 indicate a hard electrical fault?
.....or can you get a P001 even if there's a mechanical issue and no electrical issue?

 

I was under the impression that P0001 is a general fuel system fault. Or maybe the connector wasn't plugged in fully, or the clip is damaged somehow?

 

The connector was on the HPFP solid.....but that was a good thought, so I checked up on it.
I just went out to the car and measured the resistance of the entire circuit from the main connector (the one that plugs into the DME.
With the connector plugged into the fuel volume control valve on the HPFP....
.....measuring between pins 17 and 45 of the connector that I unplugged from the DME...
I get 2.8 Ohms which is what I got when I measured the fuel volume control valve directly.
Sounds like the connection to the HPFP is good.
The connector and DME pins look good as well.
I think my path forward is to replace the fuel filter.....then if I still get the same issue.....I'll replace the HPFP.

 

I just replaced the fuel filter and reassembled everything.
Surprisingly it’s running well again.
I cleared the codes and took it for a few rest rides…..no codes or check engine light currently.
I guess I’ll just wait and see if the issue reappears. If it does, I’ll throw a HPFP on it.

Below is the filter. Not clean but not horrible.
It’s the original filter. 2009 with 70k miles.
The car sat for about 18 months between the time the previous owner dropped the valve and I finished the engine rebuild…..but everything in the tank is crystal clean and clear.
Oh well…..time will tell what the issue really was / still is.

 

1 week in and the car is still running beautifully.
Previously, even when it ran good and had power, it would have rough starts or weird little hesitations sometimes. Nothing major…..just enough to notice every once in a while.
After replacing the filter, all those little things are gone.
I’m still not ready to call it fixed…..but it seems promising.

 

Final check in:
car is still running great.
I’m calling it fixed.

 

Darn!!!! It’s not fixed…..it’s doing it again.
runs like crap when you first start it up.
Came on gradually again, and now it’s consistent.
Most of the time, once you start it a couple times and give it some gas (in neutral) it will clear up and run fine…..full boost, good acceleration, all that good stuff.
With that in mind, I thought it really sounded like a leaky injector.
I replaced the injectors….no change.
a bit of a waste of money but not horrible since the car now has 97,000 miles.

Since the injectors didn’t fix it, my next thought was the HPFP….although I’m not getting any low fuel pressure codes….only random misfire codes on all cylinders.

as a last ditch effort, I replaced the fuel filter again since it had about 20k miles on it. Last time the new fuel filter made the problem go away for a few months…..this time it didn’t help…..but…..When changing the fuel filter, I did notice the fuel in the filter housing was very dirty / black and the fuel filter was black. I didn’t expect the filter to be black already since it’s only 20k miles old.
the fuel in the tank looks normal.

Filter with 20k miles vs new filter

Fuel from filter assembly

Fuel in tank

Fuel in filter assembly


the electric fuel pump also seems a little noisier than before….kind of sounds like a GM in tank fuel pump before it goes bad.

With this in mind, I ordered a new electric fuel pump assembly.

as soon as it arrives, I’ll update the thread.
Hopefully this fixes it and I don’t have to put in a HPFP as well.

pictures attached.

 

My guess is that something in the pump is deteriorating and putting all that dark material into the fuel filter housing.
This is just a guess….but something is making that fuel dirty and for $370 I’ll take the chance instead of troubleshooting for another 8 hours.

 

Ok…..here are some updates.



1 - replaced the in tank fuel pump. Didn’t fix the running issue but the new one sounded WAY better than the old one….so the old one needed to be replaced.



2 - went to replace the HPFP. Bolted the new one in, but before hooking the fuel line to it, I decided to take a look at the fuel that was getting pumped to the HPFP.

Under the hood, with the fuel line disconnected and pointed into a mason jar, I opened the door to pump some gas into the mason jar.

I looked at the fuel and saw some small black particles. Not a lot….just some.



3 - I went back to the filter assembly to check for dirt. The assembly and filter were all clean this time (I’ll check the old fuel pump later to see if it was really degrading and creating the black particulate).

I connected a hose to the fuel filter outlet and rigged up a battery / button switch to turn on the electric fuel pump.

I pumped a few mason jars of fuel then it finally started coming out clean.

I then went to the engine compartment and pumped out a bunch of fuel there to flush the line. It took about 6 or 7 mason jars of fuel before the fuel ran clean.



4 - with clean fuel pumping to the HPFP, I connected everything back up and took it for a test drive……success!!!



Starts and runs beautifully!!



The HPFP was obviously the culprit…..but I’m confident the electric fuel pump was having issues. Replacing the fuel injectors may have been wasted money….but the car has 90k miles so probably not too much of a waste.

Since I was doing all this stuff, I also replaced plugs and coils (after I replaced the HPFP) so I can be completely done with all tune up components.



The car runs great now…..but that was a bit expensive

Filter assembly is clean now

Filter is still clea

Pumping fuel from the tank

DIRT!!


MORE DIRT!!