Air Filter replace and maf sensor clean

[rickyf10]

So I decided to upgrade my intake part with limited budget. A high flow filter would be my first choice
From what I know, oiled filters may cause maf problem, so what I got is afe pro dry s filter.

Driver side air intake box got stuck in the engine bay for some reason, I took 6 screws out and managed to take both charcoal filter and air filter out. It’s tough one honestly btw, the large screw that holds the driver side air box is t40 (should be t27 from I know) which is really weird

Good bye dirty filter

At this point I also took out maf sensors to see how dirty they were cuz my idle sometimes is erratic. There are some oil on the plastic cover (where is the oil from????)


I found oil in the intake tube also. Can someone explain this?


It took me 1hr or so to finish all this (driver side air intake box was really a pain )
I now can hear my turbo spool and feel slightly quicker throttle response
For power gain, I don’t know since I don’t really wanna spend $$$ on dyno for some numeric data

[BeachM5nster]

Originally Posted by rickyf10

So I decided to upgrade my intake part with limited budget. A high flow filter would be my first choice
From what I know, oiled filters may cause maf problem, so what I got is afe pro dry s filter.
Attachment 2166384
Driver side air intake box got stuck in the engine bay for some reason, I took 6 screws out and managed to take both charcoal filter and air filter out. It’s tough one honestly btw, the large screw that holds the driver side air box is t40 (should be t27 from I know) which is really weird
Attachment 2166385
Good bye dirty filter
Attachment 2166386
At this point I also took out maf sensors to see how dirty they were cuz my idle sometimes is erratic. There are some oil on the plastic cover (where is the oil from????)
Attachment 2166387
Attachment 2166388
I found oil in the intake tube also. Can someone explain this?
Attachment 2166389

It took me 1hr or so to finish all this (driver side air intake box was really a pain )
I now can hear my turbo spool and feel slightly quicker throttle response
For power gain, I don’t know since I don’t really wanna spend $$$ on dyno for some numeric data

yea mine had oily residue inside the piping too. not as heavy as yours looks though, i have no idea why..but someone will know.

and yea those non-euro spec charcoals suffocate the intake pretty good

congrats on your first step on a very slippery slope! lol

[arucano]

There are two possible sources for the oil. One is the crank case breather system or a leaking turbo seal. The former is the more likely one given that it is also found on the air flow sensor.

[rickyf10]

Originally Posted by arucano

There are two possible sources for the oil. One is the crank case breather system or a leaking turbo seal. The former is the more likely one given that it is also found on the air flow sensor.

Thanks for explanation!

[rickyf10]

Update: just got cel light on. No idrive warning. So I checked the code and it was 118011 and 118111, both are mixture control: mixture too rich.
They remove easily since they are not present when I pull over
(My car is currently running on stage 1)
Is it related to air filter change? Or should I ignore it?

[94jedi]

I have the same filters! Oddly, no oil in my intake though; didn't clean the mafs either although maybe I should give that a shot next time I'm in there.

[chris-w]

So I just cleaned my MAF sensors and managed to drop one of the screws in to the engine bay. Such an idiot.

[Blaxwil]

Originally Posted by M5theonlyone

What do you clean the MAF sensors with, alcohol?

Only use this to clean your MAF. I did this a few months back after getting a CEL. Check engine light came off immediately after cleaning the MAF.

[M5Rick]

Originally Posted by Blaxwil

Only use this to clean your MAF. I did this a few months back after getting a CEL. Check engine light came off immediately after cleaning the MAF.

They sell it over here, did you unclip your MAF sensors then spray them out of their enclosures..

[huesey1974]

Originally Posted by M5theonlyone

They sell it over here, did you unclip your MAF sensors then spray them out of their enclosures..

That's the way I done it. slightly unstable idle sorted.

[Blaxwil]

Originally Posted by M5theonlyone

They sell it over here, did you unclip your MAF sensors then spray them out of their enclosures..

Yes, unclip and completely remove both MAF. Throughly use the spray all over but concentrate on the metal and opening where debris and oil collect. Let them air dry for at least 30 minutes. Improved gas mileage and will certainly smooth out the idle.

[M5Rick]

Originally Posted by Blaxwil

Yes, unclip and completely remove both MAF. Throughly use the spray all over but concentrate on the metal and opening where debris and oil collect. Let them air dry for at least 30 minutes. Improved gas mileage and will certainly smooth out the idle.

Thanks and it's good you don't have to wipe it with a cloth.Mine wasn't playing up or anything but with 35k miles it'll do no harm to clean them..preventative maintenance.

[huesey1974]

Yeah defo dont touch the sensor, just spray and let dry.

[R.G.]

Did this yesterday. Only about 25k on the clock and has a lumpy cold start. Zero improvement so new plugs are on order.

[MPNeverDie]

I got the CEL with code E12C1C. I took the car to the dealer, they told me that it was the Mass Airflow sensor getting the wrong data because it was covered with oil all around. They found out that my crankcase ventilation hose is leaking so that I got some oil in the pipe.

They asked me $600 to replace the hose, which is fine for me. For the MAF sensor, they asked me $1.3k to replace them. Does it really need to be replaced? or I can just clean it myself? (My car is 45k miles and 8 years old.)

[Craze]

They are like $1200aud for both mafs new

[Solo_M_Tech]

Get the Bosch mass air flow sensors from fcp euro. They are the exact part that comes in the bmw box ( part numbers are identical) and are a fraction of the cost.

[MPNeverDie]

Thanks for your replies!

They quoted me $1200 for MAF and $600 for Crankcase Vent Hose. And I also have the door actuator need to be replaced which was quoted $1100. I was lucky that my extend warranty approved everything, so I only need to pay $500 deductible.

After replacing the MAF, the car runs very smooth when pressing the gas paddle. I will try to clean it every year thereafter