I'm stumped. I purchased an abused 2008 Cooper base. N12 motor, 6 spd, 150,000 miles. Found signs of major sludge in the motor. I have done the following:
Engine oil flush, sludge is gone
Pulled the pan, no signs of pump failure
New OEM plugs
New OEM fuel filter
New OEM air filter
New Vanos solenoids(they were shot)
New fuel feed line (very spongy)
Cleaned cam position sensors(had sludge buildup)
Cleaned MAF sensor, Throttle body and intake boot.
New oil pressure switch

Car runs good at this point. Well, up until the motor is warmed up, and I have to stop in traffic. As soon as the car stops moving, the idle drops 100-200 rpms to about 500rpms, acts like it wants to stall, and the idiot light for oil pressure comes on. Blip the throttle to about 800 rpms, it goes away, and no rough idle. Only runs rough under this condition. At speed, full power, runs great. No codes being thrown at this point.

I assume I'm chasing a vacuum leak. Any ideas? My vacuum pump doesn't appear to be leaking oil. Does anyone have a vacuum hose schematic?

Everything that I have done has helped, but apparently only took care of the symptoms.

 

Forgot. Changed the oil w/ 5W30 Castrol synthetic, used OEM filter.

 

Since there was sludge, be sure to change your oil much sooner than usual now. It seems the poor MINI was very neglected. Are there any codes present in the system? If you have access to it, try to smoke test the system to make sure there aren't any vacuum leaks.

 

I have changed the oil four times at this point. I plan on doing a 3k interval until I hit 160k. The oil isn't my issue at this point.

No codes coming up. Any chance of you having schematics? Lots of places for vacuum connections to hide in that tiny engine bay.

 

2008 R56 MINI Cooper ( NON S )

RealOEM.com - Online BMW Parts Catalog

 

I pulled the air cleaner after starting the car, and turning it around in my driveway. I found a puddle of fuel on the intake under the injector that is next to the feed line. May I assume that a leaky injector/s would cause those symptoms?

 

I installed a new fuel rail, no more fuel leaks. Idle is smoother now. Still have this issue of the idle dropping/oil light coming on. I shut the car off, and then restart it, idles at 800-850 rpm, and no oil light.

I went to clean the connectors for the throttle body and MAF sensor, and noticed the orange wire coming out the MAF pigtail had cracked insulation, right where it exits the pigtail. Uncovered more of the harness, found the wiring still flexible and not damaged. Brittle right at the pigtail.

While I search for another pigtail, does anyone know what that orange wire goes to? What input to the computer is being screwed up by this?

 

thanks for the update.

That part of the wire harness that goes back to the ECU. I would see if there is a break in the harness , cut it and resolder then end then shrink heat a new plastic sleeve on. Sounds like that the issues.

 

Unfortunately, it's cracked right at the plug. I haven't been able to find a pigtail in any of the local yards. Anyone have a source for a new pigtail for the MAF sensor? It would be overkill for a new engine wiring harness for one plug in. If not, I'll be contacting the yard I got the fuel rail from.

I will try to trace the rest of that harness for any other breaks or cracks.

Thanks

 

Diagram #17

RealOEM.com - Online BMW Parts Catalog


https://www.ecstuning.com/Search/Sit...419/ES2675556/ x 1

then

https://www.ecstuning.com/Search/Sit...932/ES2672724/ x how many wire you have

Then the gommet x the number of wires, this seals the wire to the plug .

https://www.ecstuning.com/Search/Sit...411/ES2673549/



Strip the wire of wire back a bit, you have some room/ slack in the harness. Then cut and reclip the ends.