[SerenVoX]

Hoping for some advice for trobleahooting, before considering compression test as that I not so easy where I'm at. Checked piping, all looks good to me.

Code is intermittent, sometimes CEL on dash, can be off for weeks before illuminating.. but I believe the code is always read tho. Symptoms that might be related are when car hasn't warmed up, switching from 1st to second is really drawn out.. like it dosent switch gear until 3k-3500k rpm. Just 1st to 2nd. According to logs car is Not lean or rich AFRs fine. Will make boost target or 1-2psi shy overall on wot so I don't know if it's a small leak.. can anyone reccomend starting with with O2 or plugs or something I may be missing before looking for a tiny leak..

Car is strong and on e30 with bm3 stg2 e30 OTS tune.
Pure stg2 turbo and FBO.

Thanks!

[Anthony235]

I run the same map. Perhaps share a log with us.

It could just be it's picking up STFT adjustments.

[SerenVoX]

Originally Posted by Anthony235

I run the same map. Perhaps share a log with us.

It could just be it's picking up STFT adjustments.

Hey Anthony, thank for taking the time to help . Here's some logs forgot to mention I'm on N20 plugs.

Sport+ Auto Shifting Stg2 E30 OTS
http://www.bootmod3.net/log?id=5af87feed10b430b6142ce49

Sport+ Manuel Shifting Stg2 E30 OTS
http://www.bootmod3.net/log?id=5af87fb9d10b430b6142ce47

Cruising log Stg2 E30 OTS
http://www.bootmod3.net/log?id=5af87ee3d10b430b6142ce43

[Anthony235]

Trims look good. AFR looks good. How many times have you gotten an actual CEL with that code? Do you have an intake (might be MAF sensor related)?

You just run the normal e30 OTS tune with PS2? I wonder if you need a custom map. All the extra air from that turbo might be causing the lean CEL.....?

[SerenVoX]

Originally Posted by Anthony235

Trims look good. AFR looks good. How many times have you gotten an actual CEL with that code? Do you have an intake (might be MAF sensor related)?

You just run the normal e30 OTS tune with PS2? I wonder if you need a custom map. All the extra air from that turbo might be causing the lean CEL.....?

I've had this CEL on and off many times, over the past couple months. It was only after I had the PS2 and Port injection(currently installed but disabled till this is sorted) and the N20 plugs installed that I jumped into a full E85 custom tune that this first appeared. So I told the tuner and after many revisions it kept reappearing.

Fast forward now and Ive flashed to stock/93 OTS/E30 OTS and the code still appears even if CEL is not illuminated it will still show on BM3 read codes. So this rules out tune related or fuel related.
And plus like you mentioned my logs show good.

This leads me to believe its hardware related, but that's where I'm not sure where to start.. Car has 18k miles on it and the N20 plugs 1k miles.. The code being read on BM3 as (118001 mixture control: mixture to lean) and what you see in the picture above on OB2 reader.

I'm not sure which component to check or replace first..


P.S. My dinan Intake has never given me an issue and have been on the car for many miles before this.. I could consider replacing filter and resealing box if that might fix..

[Anthony235]

This is a wild shot, but have you tried unplugging the MAF harness at the intake? Try driving with that for a bit.

Here is a good general article. They mention MAF, fuel pressure, and vacuum lines. All things that might be an issue with your recent mods.
https://www.fixdapp.com/blog/p0171

[SerenVoX]

Originally Posted by Anthony235

This is a wild shot, but have you tried unplugging the MAF harness at the intake? Try driving with that for a bit.

Here is a good general article. They mention MAF, fuel pressure, and vacuum lines. All things that might be an issue with your recent mods.
https://www.fixdapp.com/blog/p0171

Hey Anthony this was very informative. If I unplug the MAF entirely, could you explain how that would correct the issue or what that does?Ill start there as its the easiest to remove or clean..

Ill then try the soapy water test. Im wondering if between the intake manifold my port injection bar there is a leak.. Doubtful its fueling as I would see that in the logs? As for exhaust leak, where specifically would I check, at the turbo and DP? O2 sensor would be last thing to troubleshoot..

Thanks again!

[Anthony235]

Originally Posted by SerenVoX

Hey Anthony this was very informative. If I unplug the MAF entirely, could you explain how that would correct the issue or what that does?Ill start there as its the easiest to remove or clean..

Ill then try the soapy water test. Im wondering if between the intake manifold my port injection bar there is a leak.. Doubtful its fueling as I would see that in the logs? As for exhaust leak, where specifically would I check, at the turbo and DP? O2 sensor would be last thing to troubleshoot..

Thanks again!

Don't actually remove the sensor. You should be able to just unplug the harness where the sensor is. Our cars run closed loop so it shouldn't effect much (if anything). Lots of people run without it to clear up idle issues with intakes. I'm just curios if if it fixes your CEL issue. If it does you could have a bad MAF sensor. But that usually has it's own CEL.

We have two sensors in the cat/downpipe. One is just for emissions and that's the one our tunes usually disable (O2 sensor).

The other should be for AFR and the one you should look at. Could be a bad sensor or exhaust leak, but I would think a leak big enough for it to throw a code would be heard outside the car as well.

[SerenVoX]

Originally Posted by Anthony235

Don't actually remove the sensor. You should be able to just unplug the harness where the sensor is. Our cars run closed loop so it shouldn't effect much (if anything). Lots of people run without it to clear up idle issues with intakes. I'm just curios if if it fixes your CEL issue. If it does you could have a bad MAF sensor. But that usually has it's own CEL.

We have two sensors in the cat/downpipe. One is just for emissions and that's the one our tunes usually disable (O2 sensor).

The other should be for AFR and the one you should look at. Could be a bad sensor or exhaust leak, but I would think a leak big enough for it to throw a code would be heard outside the car as well.

Hey Anthony, so my CEL light went off yesterday. So it was on for 3days then disappeared. Just like ive stated before its intermittent. I hooked up the OBD reader again with it off and this time it reads the same code as stored instead of stored and pending.


Anyways, Im gonna disable the MAF this weekend and see how goes. As for the AFR sensor you mentioned, Id imagine that would show in my logs as being bad? I think we have narrowed this down to a possible leak exhaust/vacuum and need to be thoroughly inspected for such or simply a MAF sensor. Thanks for all the advice bro!

[Anthony235]

Originally Posted by SerenVoX

Hey Anthony, so my CEL light went off yesterday. So it was on for 3days then disappeared. Just like ive stated before its intermittent. I hooked up the OBD reader again with it off and this time it reads the same code as stored instead of stored and pending.


Anyways, Im gonna disable the MAF this weekend and see how goes. As for the AFR sensor you mentioned, Id imagine that would show in my logs as being bad? I think we have narrowed this down to a possible leak exhaust/vacuum and need to be thoroughly inspected for such or simply a MAF sensor. Thanks for all the advice bro!

No problem!

You're right, I would think a faulty AFR sensor would show in the logs with erratic AFR readings.

If it's an exhaust leak the leak would have to be before the AFR sensor which would also show in your logs as running lean, but it's not. Unless there is more to reading the AFR than just that sensor.

Perhaps the car and DME are able to throw enough fuel at it to compensate, but still recognize it's an issue so it throws the CEL. This would explain why the logs look OK, but then the STFT would be pretty high (they max out at 1.3) and yours seem normal.

Cars suck sometimes.

You're using JB4 to control PI I assume. I know you said it's disabled, but are you sure the JB4 isn't causing an issue??? Is still physically hooked up?

[jb-slow]

What code is it throwing? There's no specific code in any of those old posts.

[SerenVoX]

Originally Posted by bmw5sport

What was the final income on this issue? I'm having the exact same problem.

Are you referring to this code: 118001 mixture control: mixture to lean?

If so, then I can say that my car will still get this code, ONLY when I'm running E30 or more.. I swear that its just a fluke, because my car gets it on the E30 OTS maps from BM3 and on the custom full e85 tune. My tuner has stated its nothing to worry about since logs are just fine. So I guess no, I never could figure out why my car has this CEL code on ethanol. But one thing for certain is that as soon as I go back to 91oct it dose not pop. Only on ethanol. I have had new MAFs and new O2 sensors and car is leak free. Like I said even on the E30 off the shelf maps it pops but car is not lean at all.

[SerenVoX]

Originally Posted by bmw5sport

Mine just keeps giving the code. No other signs at all on ethanol. I'm wondering if I have an exhaust leak or bad injectors. I do get rough start ups when ethanol is on the high end. That's it. Just hate to see the CEL pop up. Especially if the wife is driving the car.

Its hard to say what could be causing mine since its not constantly on, only when I change fuel. My car is heavly modified, Pure stg2 turbo and full bolt ons to include st2 HPFP and stg3 LPFP. But im 100% CEL free on all maps except ethanol. At this point the only thing I could consider changing would be my Injectors, but I have no real reason to. My logs are perfect.

My recommendation would be to run some logs at WOT and have those looked at first. Assuming your logs show no issues and you are leak free on all piping (intake, charge pipes, intercooler) then you could try replacing O2 sensors, MAF sensor and consider running stock Intake if your not already. Lastly you could try the injectors. Other than that, if your logs are showing good AFR's, SFT and no leaks then you could just use Bootmod3 tuning platform to supress that specific code so the CEL isn't illuminated.

Oh and you can disable cold start with bootmod3 as well. This has been known to fix any rough idle when starting the car with ethanol map.

[Sadn20owner]

Did anyone figure this out I am having the same issue with code 118001 and a intermediate cel. I’ve brought it to a bmw service advisor 2 times and they haven’t been able to figure it out. If there is no clear answer would you guys recommend Turning off this code with bm3?

[Danil.m235i]

Originally Posted by Sadn20owner

Did anyone figure this out I am having the same issue with code 118001 and a intermediate cel. I’ve brought it to a bmw service advisor 2 times and they haven’t been able to figure it out. If there is no clear answer would you guys recommend Turning off this code with bm3?

I just had the same issue. heres what i did to fix it.
my mods are the dinan carbon intake, VRSF catless dp, and FMIC, BMS charge pipe and turbo inlet pipe, 1 step colder plugs gapped @ 0.02 and bm3 flex fuel kit.

I ran the car on the OTS stage 2 flexfuel map on map 2 for 91 octane, and got the mixture control code 11CF30. for lean condition. I messaged BM3 support and based on logs it was due to the carbon intake (due to it being a different design or something with airflow) car would only throw this at idle or startup. After getting an updated map sent over light did not come back on until I got the flex fuel kit and began running ethanol. My logs all looked great, great AFR and basically perfect STFT but car was just throwing that code regardless.

Solution:: When you go to your map settings (or configuration) BM3 has fairly recently added the option to selection which HPFP you are using. MAKE SURE IT IS SET TO OEM. Then reflash. along with other settings such as o2 sensor disabled if your catless etc. So if go through and make sure its set to OEM because since doing that the code hasn't returned in over 500+ miles.

Good luck!

[Danil.m235i]

Originally Posted by SerenVoX

Its hard to say what could be causing mine since its not constantly on, only when I change fuel. My car is heavly modified, Pure stg2 turbo and full bolt ons to include st2 HPFP and stg3 LPFP. But im 100% CEL free on all maps except ethanol. At this point the only thing I could consider changing would be my Injectors, but I have no real reason to. My logs are perfect.

My recommendation would be to run some logs at WOT and have those looked at first. Assuming your logs show no issues and you are leak free on all piping (intake, charge pipes, intercooler) then you could try replacing O2 sensors, MAF sensor and consider running stock Intake if your not already. Lastly you could try the injectors. Other than that, if your logs are showing good AFR's, SFT and no leaks then you could just use Bootmod3 tuning platform to supress that specific code so the CEL isn't illuminated.

Oh and you can disable cold start with bootmod3 as well. This has been known to fix any rough idle when starting the car with ethanol map.

Did you have the map configuation HPFP setting set to your HPFP accordingly? it seemed like with an update theyve added some new settings to configure.