[majkic]

Hello everyone,

This is my first post and I want to share problem I had with Mixture too rich error I had and to give you background how I identify problem as it was not so obvious on my BMW 330e F30 2016.

So, problem was appearing for long time and few mechanics didn't know what is root cause, assumption was to have air leak or similar.
Car was driving fine, idle was fine, no visible issues except check engine and error code 118002 Mixture too rich.
Was driving for some time and after clear code it would come back after few weeks/months.
So I installed bimmerlink and bimmercode to check errors and code some things.

At some moment when check engine appeared, I checked Memory Info in bimmerlink and notice: 11AA08 High-pressure fuel system, plausibility: pressure reduction too high

Based on this I monitor rail pressure:

• Setpoint rail pressure control [blue line]
• Filtered rail pressure actual value (absolute pressure) [orange line]

At first glance everything looked normal, but when I plotted the values ​​on the graph there were places where pressure is lost (see attachments below).
Also, after car is turned off, there was visible lost of pressure (~10bar/s)


In meantime, I got ISTA+ to read errors and see if I will find out something else, but what surprised me is that 11AA08 was not detected at all..

So what is actually happening is that fuel is lost through the HPFP to engine and it goes to oil. After some time, fuel evaporate and goes back through the PVC system and detect mixture is too rich...
Fuel lost happens when pressure shall be decreased from 200bar to somewhere in the middle (150-170bar), and no pressure loss in idle or during load.

After replacing HPFP, pressure behaves normal. No drops, after power off it stays at same pressure and no 11AA08 as well, will see for 118002..
I will add graphs after the HPFP change.

Also did oil and filter change, asked mechanics to check if it smells as fuel inside, he say not so much, little bit.

[majkic]

After replacement of HPFP, 118002 was coming back each time after reset.
Problem seems to be in mixture adaptations.
After reset of those with ISTA+, it seems OK. No error.

[bluesport]

Hi, I'm having this same situation with my 330e b48. DME 118002 Mixture control: Fuel-air mixture too rich. Few years now. I reseted the codes, it took like half year or more to come back, usually in the winter time, but few times in +20degC ambient too. Now it is constantly on.

No symptoms, no rough running, no loss of power etc. No any other fault codes.

Interestingly there was also single occurence of DME 118401 Mixture control: Mixture too lean, deviation too high, one year ago.

Software is newer than one mentioned in the bulletin (and Euro car so maybe not even relevant) https://static.nhtsa.gov/odi/tsbs/20...61546-9999.pdf

Conditions that are consistent over each occurence:
* RPM low but not idle: 880 to 1050
* engine oil hot: 76 to 105 degC
* lambda actual: 0.96..1.02
* lambda control value, output: 1.18 .. 1.31

I reseted the adaptations but that didnt help. I'm not sure if that was succesful, I noticed no difference.

Did not notice smell of gasoline from warm engine oil cap, but it is a bit difficult to say.


Would like to know, did the adaptation reset help for you? Has the fault come back since?

[Sub1]

Interested to see of Majkic resloved the issue.

Exact same problem here too. Rich mix EML re-appears few months after resetting adaptations & clearing fault code.

This time I decided to change HPFP, Upstream O2 sensor & all four injectors, hoping this time its fixed for good.

[Romy]

Originally Posted by Sub1

Interested to see of Majkic resloved the issue.

Exact same problem here too. Rich mix EML re-appears few months after resetting adaptations & clearing fault code.

This time I decided to change HPFP, Upstream O2 sensor & all four injectors, hoping this time its fixed for good.

Did u fix it? My ltft are -30, stft at 0

[Sub1]

I am not too clued up with with trim values to be honest, Ista was showing to reduce fuel values by 30%
Yet to do more research to better understand

Just been a month now, only time will tell if it will trigger EML. Mine was driving very well but since changing these parts, the car drive noticeably smoother & noise reduction from new cam follower whilst doing HPFP.

First time this occured, BMW specialist diagnosed Fuel tank temp sensor & breather valve. This did not solve, therefore didnt go back to them & i decided the injectors (with revised version ending 396) etc.

Whilst doing injectors I pulled out spark plugs. No fuel/oil fouling, slightly dark on top edge of thread on each plug.
No fuel smell on engine oil filler cap.
Injectors were dry but tips were sooty. (First gen injectors ending 990)
No obvious sign old O2 sensor was bad.