Variance between AFR in banks

pysical

Sergeant
Jun 16, 2017
450
105
0
Ride
2009 335xi E90
Heres the story....

Car was running fine so I decided to run some Liqui Moly Jectron Fuel Injector cleaner through it. After filling the tank full of 93 and putting a single bottle in I drove it for roughly 20 miles. After that I got an issue (turbo outlet silicone popped off) and the car sat for about a month. I got it all fixed and now I am getting a AFR difference between bank 1 and 2. Bank 2 sits roughly around 14.5 and bank 1 sits around 15.4.

The car is single turbo and I have ADV sensors. The first code I got was 2C31 then later the same day I got 2C6B. My tune is set to only use one post turbo o2 sensor which is bank 2.

Things I have done:
Swapped bank 1 adv sensor with another sensor - No change
Swapped post turbo o2 sensor with another sensor - No change
Reset adaptations - No change

Is it possible the fuel injector cleaning could have messed something up? I haven't had a chance to check the plugs or test injectors. Injectors are index 12 with less than 500 miles on them. Same with plugs.
 

pysical

Sergeant
Jun 16, 2017
450
105
0
Ride
2009 335xi E90
Oh. Yeah so my car caught fire and I rebuilt it. Of course the HPFP and injectors were replaced with brand new but I wanted to also just run it through the tank and everything since the fire I guess shorted the fuel pump and my tank went completely dry. I don't really care for it either but I just wanted to give it a shot for the chance that it would help.

BUT, I ended up figuring out the issue. I guess the cleaner was the issue. I took it out and filled it up with fresh 93 and drove for about 10 minutes to pump it through and then cleared adaptations and then drove some more and it is where it should be. Its just weird to me that if it was causing a issue why it was only having a AFR variance in one bank.
 

Slowagon54

Corporal
Aug 21, 2020
165
62
0
Ok, so the whole engine has only 500 miles on it, right? I dont think a cleaner can do such a thing. 2C31 usually indicates a bad o2 sensor or an exhaust leak near the sensors/downpipes. You may also check the downpipe gaskets. Did you re use the old - and are you sure you throw them in before install?
 
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