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So I have a new to me used 2013 MCS All4 with 200,000 kms on it. It was running fine when I bought it and after a few tanks of gas I started to see fuel mileage drop and started digging around this site for answers. After plugging in my Topdon OBD reader I received the following codes:
P0100 - Mass or Volume Air Flow A Circuit
P0102 - Mass or Volume Air Flow A Circuit low
P0172 - System Too Rich Bank 1
I purchased a new Bosch MAF, however, as soon as I install it and clear codes I cannot get the car to idle smoothly. It seems to try and adjust but never levels out and then I recieve misfire across all cylinders and it eventually stalls. When I install the aftermarket MAF the car at least idles smoothly and is drivable. I have tried to test voltage on the MAF connector but seem to have some fluctuating readings so will have o try again another time.
I have since been chasing my tail trying to figure it out. I had noticed fuel smell in the oil, spark plugs full of carbon, and I managed to damage the boot on one of the coils so I ended up replacing all four, PCV diaphram, air filter, MAF, coils and plugs. Changed the oil and checked all the vacuum lines I can looking for leaks as I read that unmetered air could cause increased fuel consumption. The only place I saw any sort of gap was on the backside of the air intake housing where the three clips didn't seem to close tightly. I wedged some washers in there as a test but no change to the codes. I am not sure what I did exactly over the last few weeks but at one point I was able to drop the g/s on the MAF to around 5 from the original readings attached below.
There is no major oil leaks and I am not noticing oil consumption however, it could be because of the fuel mixing with the oil. The turbo looks clean and dry hoses look dry as well, however, there is some brownish staining inside the hose presumably due to fuel vapour. The previous owner mentioned that the timing chain was replaced a couple years ago as well. In my troubleshooting and looking for leaks I noticed crystallization under the oil filler cap, again probably fuel leakage.
I am trying to figure out, before throwing money at parts like new valve cover, fuel injectors, etc, if I am missing something. So I am retracing my steps to the initial codes that are still present and hoping to find some clarity on where to go.
The nearest Mini dealer is over 3 hrs away and I don't have a smoke machine and have not checked for vacuum leaks with starting fluid or propane torch.
Any guidance is truly appreciated. Will purchasing a bimmerlink compatible OBD reader provide any more details then what I currently have?
I had tested using the propane torch method and then attempted using a DIY smoke generator and first tried the vacuum check valve to no success. Then I was going to try on what I believe is the evap valve (back side of intake) but noticed when I removed the air filter box that this valve port did not have any hose attached to it. Can one tell me if it is supposed to? It doesn’t appear that there has been one attached for a while.
What is this? Should not have a vacuum line on it and if so, where does it connect?
I would use the starter fluid method. Looking at the photo, I really can't tell what we're looking at. Maybe clean up the area a bit and take better photo.
I just found this on the net. It may not be used on the N18 but it is located at the bottom of the intake manifold. Same one as the screwdriver is pointing to
