Running too lean 2014 f10 m5

[Hairygorilla]

just hit 64k miles and engine light has come on it says that my engine is running too lean.

Has anyone had similar experience and might know the problem?

[BMWSauberF1]

Originally Posted by Hairygorilla

just hit 64k miles and engine light has come on it says that my engine is running too lean.

Has anyone had similar experience and might know the problem?

Im having the same issue on my M5 it’s saying mixture too lean large deviation on both banks. I have BMS Intakes, Downpipes, and BM3 Stage 2 91 OTS map

[Hairygorilla]

Originally Posted by BMWSauberF1

Im having the same issue on my M5 it’s saying mixture too lean large deviation on both banks. I have BMS Intakes, Downpipes, and BM3 Stage 2 91 OTS map

what millage are you on, my car is stock, I got it recently remapped thinking it might help fix the issue.

[Bantham1]

I have the same problem. Bank 1 is showing to be 10 percent positive deviation from bank 2. Long term Fuel trims are positive on bank 1 around 15 percent at idle. I have smoke tested, replaced pcv hoses, swapped mass air flows, oxygen sensors and no change. I have around 62k on mine. My car only has exhaust and high flow air filters. No tune. Check your long and Short term fuel trims and see what they are on each bank. I don't know what is causing this. Seems to be a common problem that is difficult to track down. Can someone without this issue post long term fuel trims at idle and also maf and fuel pressure from low pressure pump and high. It is air or fuel related and suspects are injectors, fuel pumps, air leak somewhere, ecu, or maybe vanos?

[BMWSauberF1]

I have 86k miles, Well I know when I was changing my DP’s a couple weeks ago to the catless ones I accidentally cracked the Pcv hoses however I did wrap the crack in super33 3M electrical tape which is super flexible and seals stuff really well as well as foil tape over the top I figured that would be fine for the time being and I don’t see any codes due to the Pcv system. I also have cleaned my MAF’s a couple times with MAF cleaner I made sure they look brand new. I’m not sure the pcv’s are leaking at all but if they were leaking slightly would that throw that too lean large deviation code on both banks? Could my MAF’s both be bad or something I mean I doubt both of them would have gone bad like that but the code comes back pretty much immediately after clearing it.

[BMWSauberF1]

Where in the logs do you see the long term fuel trims I have been trying to find the data from the MAF’s in the logs to see if they’re functioning properly.

[BMWSauberF1]

https://www.bootmod3.net/log?id=63f0...0b43c87a68d419 here’s one of my logs if anyone could check them out for me and let me know how things are looking I’d appreciate it.

[Bantham1]

I replaced the pcv as well because mine cracked when unclipped. No change from that. I notice when running cruise steady throttle bank 1 is positive 6ltft and bank 2 is negative 6ltft. Seems to be the opposite with one bank running rich and 1 lean. Could be also difficult to track down since the cross bank exhaust pulls from each bank. What boost are you running. Looks really high if that is correct.

[BMWSauberF1]

I’m running BOOTMOD3 stage 2 OTS 91 OTS map I think the boost levels are the actual boost plus atmosphere so just take 14psi off that number and you’ll actually get the correct boost pressure.

[Black Panda]

Originally Posted by Bantham1

I have the same problem. Bank 1 is showing to be 10 percent positive deviation from bank 2. Long term Fuel trims are positive on bank 1 around 15 percent at idle. I have smoke tested, replaced pcv hoses, swapped mass air flows, oxygen sensors and no change. I have around 62k on mine. My car only has exhaust and high flow air filters. No tune. Check your long and Short term fuel trims and see what they are on each bank. I don't know what is causing this. Seems to be a common problem that is difficult to track down. Can someone without this issue post long term fuel trims at idle and also maf and fuel pressure from low pressure pump and high. It is air or fuel related and suspects are injectors, fuel pumps, air leak somewhere, ecu, or maybe vanos?

When you add a High Flow intake with a aftermarket exhaust your gonna run Lean without a tune. Your car needs a tune. Tell me this. Did you get a lean code before you did your mods??

[Black Panda]

[QUOTE=BMWSauberF1;29882010]https://www.bootmod3.net/log?id=63f0...0b43c87a68d419 here’s one of my logs if anyone could check them out for me and let me know how things are looking I’d appreciate it

I'm gonna look at your logs and get back to you

[Black Panda]

Sorry just a Lil busy but I'll check it and have some answers for you by 2pm et. First thing id do though since your on 91octane is turn the boost down 3 psi across the entire rpm band. Delete codes and start there. But like I said I'll check your logs and get back to you.

[Bantham1]

I wonder why only 1 of the banks is lean if that is the case? Bank 1 is lean with high plus 16 positive ltft and bank 2 is very close to 6 on ltft fuel trims. When driving under throttle bank 1 comes back down to around positive 6. It is at idle and off throttle where it goes very lean to the point of throwing codes when cold outside. The car came like this so I don't know if it happened before mods.