Lean in Bank 2

[///M_life]

Wanted to see if some fellow members could help me pin-point my issue on a M6

My car has sat for maybe two days, fired it up this afternoon and a check engine light imeediately upon start up occured. I drove to autozone to diagnose it with their scan tool and code P0174 came up which is lean in bank 2. I drive the car overall very easy, spark plugs were changed 5,000 miles ago. The car is driving perfect, idles perfect, no gas smell, hesitations or misfires.

Any thoughts? I was thinking about testing out the pre-cat O2 sensors by switching both banks and seeing if i then get codes for bank 1.

Only other thing worth mentioning is that i do get the battery discharge notification each morning when i start up which goes away after 10 minutes of driving. I believe this is due to it not being a BMW battery because it is registered.

[Boosted M5]

Don't forget to check your MAF sensors. You're on the right track with your O2 sensors and keep in mind maybe your injectors or HPFP are on there way out do to the mileage you're at.

[///M_life]

Originally Posted by Boosted M5

Don't forget to check your MAF sensors. You're on the right track with your O2 sensors and keep in mind maybe your injectors or HPFP are on there way out do to the mileage you're at.

Ive actually had my HPFP drivers side replaced but not passenger. Bank 2 is driver side i think so would be unlikely for it to be that. I want to avoid bringing to the dealer because they charge $180 to diagnose it. But if the diagnosis shows its a failing part under warranty then the fee is waived so you take that gamble. The HPFP and injectors are under warranty until 120k

[Simple5]

Originally Posted by M3nsterm5

Ive actually had my HPFP drivers side replaced but not passenger. Bank 2 is driver side i think so would be unlikely for it to be that. I want to avoid bringing to the dealer because they charge $180 to diagnose it. But if the diagnosis shows its a failing part under warranty then the fee is waived so you take that gamble. The HPFP and injectors are under warranty until 120k

Clear the codes and remove the k&n filters and switch back to stock. See if that works.

[///M_life]

Originally Posted by Simple5

Clear the codes and remove the k&n filters and switch back to stock. See if that works.

If i check the MAF sensors will there be a way to tell if they are dirty or oiled up?

[///M_life]

I would imagine if it were injectors or something serious the revs and idles would be erratic and driveability would be different and the check engine light would pop back up immediately. So far im not too concerned...

[J11SEK]

Originally Posted by M3nsterm5

If i check the MAF sensors will there be a way to tell if they are dirty or oiled up?

Just take them out, takes 2 mins and visually inspect them..... any oil on them means a clean needed with maf cleaner ONLY! Don't touch them or try to clean them with anything also or you risk damaging them!

[///M_life]

Originally Posted by J11SEK

Just take them out, takes 2 mins and visually inspect them..... any oil on them means a clean needed with maf cleaner ONLY! Don't touch them or try to clean them with anything also or you risk damaging them!

ill inspect them this weekend for sure. i have the MAF cleaner. Since then i have fired the car up 4 times and no check engine light. Im not worried about it overall as its most likely a sensor since it idles fine and drives fine

[4point8]

try pulling the plugs on bank 2 and see if its fouled with fuel, if there is fuel present on the plugs or if it smells like fuel, most likely a bad fuel injector...

fault ur getting is mixture lean; ive had a few that faulted for the same and found the plugs fouled ... maybe before u pull the plugs, check and make sure u dont have unmetered air/air leaks in the air intake system

[M5Yams]

Originally Posted by M3nsterm5

Appreciate the advice, pulling plugs may be beyond my capabilities. However the light has not come back on, car drives perfect. It very may well come back on later on but if its taking that long for it to notice something then im sure its most likely minor like a sensor or something. Ive had a failed fuel pump already so i know what that feels like, injectors im sure as well are very noticeable when going out.

If I were you I wouldn't make light of the injector thing, most of the time people are just driving and the engine locks because one flooded the cylinder with gas.