Running lean on two banks. and other errors report

[chris-w]

I have been getting a CEL that most dealers simply turn off and it stays off for about a week then comes back. I am completely fed up with this behaviour as they are all telling me the car is fine.

I manage to download and get working a version of ISTA on my laptop and pull off a report re the errors I am seeing and was hoping someone might be able to help me decode what on earth is going on?

I recently replaced the rear drives side comfort door handle as it kept shorting out the fuse and it seemed to fix one issue but now I am seeing the front drivers side door handle is acting up!? I have noticed some weird behaviour re locking the car as well. I do not think the CEL is at all related to the door handle though which I know I can resolves myself.

See attached PDf of from ISTA. Any assistance would be greatly appreciated, im not a bad DIY'er and wouldn't mind trying to resolve this myself.!

[Dwaynos]

Do you have aftermarket intakes?

[chris-w]

Originally Posted by Dwaynos

Do you have aftermarket intakes?

As far as I am aware the car is completely stock.

[Dwaynos]

You need to be looking at live data. STFT and LTFT need to be monitored, aswell as your o2 sensor voltages. From here you can start to determine the cause of your lean condition.

I'd be inclined to try cleaning your MAFs before you start complicating things actually.

[chris-w]

I removed both MAF sensors last week and cleaned them off with MAF sensor cleaner. They were spotless and it didn’t seem to resolve the problem.

I’m pretty new to ista, regarding the live data I assume this should be done with the engine running. I’ll do a bit of reason on the Atif and give it a go tomorrow.

Thanks for the advice I’ll report back if I manage to get anything worthwhile !

[Monteblueem5]

Check the Fuel injectors Make sure that the car has a Eu5 make sure the car calls for the injectors that in the car I had the same problem and it turns out the dealer
Put the wrong injectors I. So it’s easy to check with
Insta

[chris-w]

So after spending an hour on ISTA I cant for the life of me figure out where to get the details needed to diagnose the STFT and LTFT and or the o2 sensor voltages

[Dwaynos]

Originally Posted by chris-w

So after spending an hour on ISTA I cant for the life of me figure out where to get the details needed to diagnose the STFT and LTFT and or the o2 sensor voltages

I've never used ISTA personally so I couldn't help you. Once you do find these data pids you then need to determine whether or not the o2 sensors are telling the truth. To my knowledge a vacuum leak on these engines will not cause a lean condition. As mentioned It could be injector issues, it could also be fuel pressure issues. Does the car drive fine? any noticeable loss of power?

[chris-w]

Originally Posted by Dwaynos

I've never used ISTA personally so I couldn't help you. Once you do find these data pids you then need to determine whether or not the o2 sensors are telling the truth. To my knowledge a vacuum leak on these engines will not cause a lean condition. As mentioned It could be injector issues, it could also be fuel pressure issues. Does the car drive fine? any noticeable loss of power?

Car seems to drive fine. As its currently got the CEL on I haven't been driving it hard at all. I was hoping that I might be able to see something of value on ISTA regarding fuel pressure and or certain sensors being vastly different from the one on the other bank.

As this error keeps returning on both banks and both DME's so I am starting to think it isn't one of the sensors on each side (that would be a crazy coincidence) it must be something that causes the condition on both banks at the same time? Pumps / vacuum etc?

[charlis777]

I have exactly same faults on my one. So far put in all new injectors, new plugs also did a smoke test to find any leaks but there weren't any. My fault codes appear within few minutes of driving

[chris-w]

My car is with a specialist now and it appears to be one of the wide band O2 sensors. I just bought a replacement from Bosch and he is putting it in now. Fingers crossed.

[chris-w]

Originally Posted by chris-w

My car is with a specialist now and it appears to be one of the wide band O2 sensors. I just bought a replacement from Bosch and he is putting it in now. Fingers crossed.

After replacing one wide band the engineer has requested another wide band sensor. SO I guess both are being replaced and then see where we stand.

He said he did a smoke test and there were no leaks at all, I'm yet to believe that this smoke test was done.

I also ended up getting new BOSH sensors £85 each. BMW wanted £260 for the OEM ones EACH which according to several people are BOSCH anyway!?!?

[chris-w]

OK both O2 sensors have been replaced, engineer reported the problem as 'resolved' and on the way home the CEL goes off again. I have a feeling that the approach being taken is replace parts at my expense until the problem goes away.

So far the MAF have been cleaned and two new O2 sensors have been installed. Various people have mentioned smoke test which this engineer says he did but I'm more than dubious... I might end up having to concede defeat and take it to BMW unless anyone has any other pearls of wisdom?

I heard about electrical issues with BMW's and this is my first one and I can attest to the fact I've had 3+ AMG's, 7+ Exotics and numerous other marks and this car has without a doubt given me the most trouble.

[SapphireM5]

Check all of the intake piping, air charge pipes, connections at turbos etc. just confirm nothing is loose or dislodged. GL

[chris-w]

Originally Posted by SapphireM5

Check all of the intake piping, air charge pipes, connections at turbos etc. just confirm nothing is loose or dislodged. GL

Had a quick look at all of this. I think it looks like everything post MAF should either come off and get put back on all the way to the intake and or possibly I think BMW have a pressurised smoke machine that would identify the leak ?

Checking the piping visually has already been done and looks to be a near impossible task as I cant see underneath the bottom of a lot of the pipes.

[chris-w]

Originally Posted by charlis777

I have exactly same faults on my one. So far put in all new injectors, new plugs also did a smoke test to find any leaks but there weren't any. My fault codes appear within few minutes of driving

Did you manage to figure out what was wrong and resolve it yet. My car is once again got the CEL on and I'm honestly getting bored of it. This is my first BMW and honestly I'm now starting to believe what people have told me about electrical issues...

[S_CDSM5]

Had the exact same codes. Turned out to be a bad HPFP on passenger side. Covered under extended warranty thankfully