[scottred.f32]

2014 435i xdrive FBO catless straight piped running e50 but get code on 93 pump. Getting a code for mixture content too lean happens most often when sitting idling for a bit but not always. afr on my mhd says around 14.5 fluctuating at idle slightly. looking for some tips to narrow down the issue. Thanks

[thejeremyman9]

Confused by "e50 but get code on 93 pump".

Are you saying you are running E50 fuel mix in your tank, but running a 93 octane pump gas tune?

Also, give your full mod list and tune, including version, stage, and fuel map. A log would also help. AFR at idle should be around 14.7 as that is stoich.

[scottred.f32]

Currently running acustom e50 tune from David Shoup but also had the same code come occasionally on the ots mhd 93 map.
mods: VRSF 6.5 in intercooler, dinan cold air, vrsf alum charge pipe, catless dp and 3in straight pipe to tips on exhaust, ngk plugs gapped to .020, eldor coils, spool fx150 hpfp currently running stock lpfp (had to send my 525 walbro back to fuel it for repair) xhp stage 3 trans flash. I have a data log on datazap scottred.f32

[thejeremyman9]

Really need a log, especially one when the problem occurs, so we can see if AFRs are deviating from target and how the STFTs look. Without that you are just guessing... could be O2 sensor, fuel supply issue (HPFP or LPFP), etc.

[itsrichierich]

OP, did you find the issue? I just got a code 118001 “mixture control: mixture too lean”

I’m not sure if it means my fuel or I have a vacuum leak.

[Orion4]

Originally Posted by itsrichierich

OP, did you find the issue? I just got a code 118001 “mixture control: mixture too lean”

I’m not sure if it means my fuel or I have a vacuum leak.

I chased that code (118001) for several months. It was the only one i was getting. It would occur randomly intially every couple of weeks with no apparent event triggering it. I would reset and wait for it reoccur. Became more frequent. Performed smoke checks (3) with no leaks. Did find my air pipe bracket was broken and the vent hose was developing a crack. Replaced all those and both before and after Oxygen sensors (at 144k miles), that it was prudent. Still the code keep occurring. Finally Indy and I were watching his diagnostic system with the engine running and we could see the Lean issue in realtime and since everything looked good, we decided the disconnect the MAF. As soon as we did that the mixture parameters returned to normal. Reconnect and back to bad. Ultimate culprit was the MAF (original). Replaced and no further codes.

[itsrichierich]

Originally Posted by Orion4

I chased that code (118001) for several months. It was the only one i was getting. It would occur randomly intially every couple of weeks with no apparent event triggering it. I would reset and wait for it reoccur. Became more frequent. Performed smoke checks (3) with no leaks. Did find my air pipe bracket was broken and the vent hose was developing a crack. Replaced all those and both before and after Oxygen sensors (at 144k miles), that it was prudent. Still the code keep occurring. Finally Indy and I were watching his diagnostic system with the engine running and we could see the Lean issue in realtime and since everything looked good, we decided the disconnect the MAF. As soon as we did that the mixture parameters returned to normal. Reconnect and back to bad. Ultimate culprit was the MAF (original). Replaced and no further codes.

Hmmm ok. I just brought it to my dealership, they didn't do a smoke test but a crank case test and it was "high". They recommend me to change out the valve cover. Talked to my boss and we're just going to go half on a smoke test machine. Hopefully that will give me some insight.

Trying to avoid to replace the valve cover since it's $400 my cost. Hopefully it's something simple as the MAF.

I will say, I was having idle issues with my new Turner intake a few weeks back. Swapped it out with my OEM intake and that fixed my idle issue. I thought it was because of a few missing pieces and me not taking the time to install it right, I reinstalled the Turner intake but this time without the intake cover and car ran fine, no issues. Until I got this CEL. When I got the CEL and brought the car into the dealer to get it diagnosed, I was on an BM3 E30 tune. Picked up the car after taking to the dealer, I was low on fuel and switched back to BM3 91 tune. Of course it cleared the code since I switched maps. Now, I'm back to my rough idle again. Will drive the car a bit more to see if the rough idle continues.