R56 Most liked posts in thread: Ugh! '08 R56 won't run unless MAF unplugged.

I’m more computer technician than mechanic, and when anything with an electrical connection behaves that way, it’s worth checking the cable that connects the device.

I’m sticking with my original spitball - Swap in a Known Good MAF first because it’s easiest. Grab one from a local wrecker, no need for full price on a diagnostic part. Also maybe clean the pins on the loom plug with a high percentage isopropyl and an old toothbrush. Allow to dry before reconnecting. Also that product I linked above would work as well.

If the problem persists, start checking that wiring loom for pinches, bad or loose pins. Get the multimeter out and make sure that whatever wires plug into the MAF actually have conductivity on both ends.

If the loom checks out, then it’s ECU issues next. I’m concerned that the plugging and unplugging while the system is live and running current could have messed something up. Some electronics don’t care for that sort of thing and get wonky.

It’s possible that Dave’s right and that a re-flash of the ECU would resolve it, simply because it could have gotten junk data written into a weird memory space that’s presistent if the wrong signal was messed up by unexpected voltage while powered on. In 20 some years of computer repair, I’ve seen weird stuff like that happen (it’s rare but not impossible).

Finally, that clicking sound from the engine - that only showed up after the weirdness with the MAF?

 

Ugh, that sounds like a PITA.

I’m clearly no expert, so I’m gonna spitball some off the wall stuff here (and probably be wrong)

Head to a wreckers and scavange another MAF?

Alternately, pull out your old trusty Bently Manual, and a multimeter and start checking those pinouts on the ECM? If that checks out, check the loom where it plugs into the MAF. Maybe there’s a bad pin on the connector that can be repaired by attaching a scavenged one?

It sucks that the ECM is coded per vehicle and you can’t just pull one from another wrecked car and swap it in.

 

The first thing I'd do is a smoke test and find that vacuum leak.

 

Most modern cars with MAF’s will not run without it connected.

 

On many cars, when the Mass Airflow Sensor is unplugged, the Engine Control Unit will revert to a stored map. It isn't ideal, but it will get you home with reduced performance.

 

When ever working on an R56 and above ALWAYS disconnect the battery before unplugging anything.

Sound like the ECU may need a re-flash. Something is really jacked up with the car.

 

Having just cleaned my MAF the other day - this is what I used.

https://www.autozone.com/miscellaneous-cleaners-and-degreasers/electrical-parts-cleaner/crc-mass-air-flow-sensor-cleaner/36011_0_0

No issues so far from having used it, but it has only been a couple of days. Just read the instructions on the bottle. There are some cars it says not to use it with (Lexus, for example) but MINI wasn’t on the list.

 

Wow ^^^ that’s sucks. Good luck with that. I would not trust a dealership to look at it again. You need an aftermarket Mini specialist to read the ECU and codes to see what’s going on. You may need a flash and a new or “known good” MAF to test with.

 

I know this post is years old and I hope your still around and remember the problem to your Mini not running when you had the man plugged in. So, do you remember the problem? what was causing the Mini to run better when you unplugged the maf?

 

My mini is doing the exact same thing.