E46 M3 with P0172 code only (Sytem Running Rich, Bank 1), any ideas?

Wesley Vocino

New member
Hey guys,

I have a P0172 check engine code, System Too Rich Bank 1 on my e46 m3. I went through a few cycles and this is the only code that pops up. Last year I thought it was my K&N 57 cold air intake as it was oiled in the past, so I bought a new K&N filter. Code never came back for about 1500kms, however now after taking her out from the winter I am getting this code again.

Any ideas as to what it can be? Did anyone else ever have this problem?

As I am only getting the code for bank 1 I am thinking maybe the 02 sensor (which I changed recently, but was unplugged and re-plugged after I had to swap in a new engine due to my old one blowing up. If not maybe injectors or spark plugs on 1 of the first 3 cylinders?

The car has Agency Power Headers, Magnaflow Exhaust, K&N 57 Cold Air Intake, and an Evolve Tune.

Thanks!
 
Hey guys,

I have a P0172 check engine code, System Too Rich Bank 1 on my e46 m3. I went through a few cycles and this is the only code that pops up. Last year I thought it was my K&N 57 cold air intake as it was oiled in the past, so I bought a new K&N filter. Code never came back for about 1500kms, however now after taking her out from the winter I am getting this code again.

Any ideas as to what it can be? Did anyone else ever have this problem?

As I am only getting the code for bank 1 I am thinking maybe the 02 sensor (which I changed recently, but was unplugged and re-plugged after I had to swap in a new engine due to my old one blowing up. If not maybe injectors or spark plugs on 1 of the first 3 cylinders?

The car has Agency Power Headers, Magnaflow Exhaust, K&N 57 Cold Air Intake, and an Evolve Tune.

Thanks!

Did you retrofit the OEM velocity screen from your OEM filter into your K&N? It's the screen before the MAF
 
I put the Screen from the OEM filter into the K&N Filter. Right now I have the metal screen facing the outside. On the forums some people say to have the metal screen facing the inside, some say outside, so maybe I should try having it facing the inside? But then I would worry that if the metal screen gets loose and it gets sucked into the engine lol.

I also read that sometimes the screen has to be at a certain angle to the MAF.
 
Last edited:
Had ignition issues giving that code.

Changed the spark plugs and coils parks and it went away.
 
Cool. Thanks, I will check that out. My spark plugs and coil packs are relatively new, il check em anyway though!

I realized that the metal grill in the intake was actually facing inside the engine. I maff cleaner the shit out of my maf and then installed the metal grill facing outwards. It has been 100kms without the code, but usually it varies. Sometimes comes on after 100 kms, 300kms, ect.
 
I think I might have found the problem. The precat o2 sensor for cyl 1-3, the bank 1 I was getting the code for, was touching the headers. I turned the wire a bit, and sure enough the rubber protection coating was burnt right through. I could see right through it, however looks like the wires are ok. Maybe this is why the cel would come on and go off repeatedly. I also noticed it would come on usually after longer drives of around 45 minutes, maybe getting hot enough to throw a code. I really hope thats it!!!!!
 
Back
Top