F11 M550d N57X MAF & MAP Rough Idle Fuel Economy

[DRTE30]

Hello Community,

Over the course of around 10 weeks I noticed that the fuel economy was deteriorating from about 7.8 L / 100 Km to around 14.8 L / 100 Km average! About three weeks ago I was in Germany on business and had a chance to run the car up to higher revs and hold the engine there for a bit. Upon returning home, the following morning on a cold start the motor was showing signs of hesitation, subtle sputtering and kind of a lopey idle. Once warmed up to operating temps, everything seemed fine aside from the change in fuel economy. Then I started noticing a bit of lag upon modest acceleration or low rpm up a hill. A few days ago starting up the car, the engine behaved like a cammed V8 and sounded like one.

First inclinations were bad MAF, bad MAP, or gummed up AGR/EGR valve. I went ahead and ordered a new MAF out of precaution as the one of the car is original from 2013. Installed the new MAF, pulled the MAP. MAP had signs of carbon deposits, but nothing out of the ordinary for 85,000 Km. Cleaned out the MAP and reinstalled. Started the car and had the same lopey idle. Unplugged the MAF then restarted and the engine turned over and purred like a kitten. Shut off the engine, shut off the aux power, reinstalled the harness and repeated the lopey idle. Thought to myself I either bought a bad OEM MAF or that simply wasn't the issue and the MAF controller was communicating to the ECU to retard or advance something else. I was certain the MAF would have solved the issues as those are usually all MAF related.

Let the car sit overnight. Reinstalled the new MAF again. Started up the engine, a bit of sputtering here and there but the idle ended up smoothing out to 680 rpm. I noticed quite a bit of smoke upon start up and that eye watering vapor coming from the exhaust tips and figured some of the carbon I may have knocked loose cleaning the MAP was burning off during combustion and the ECU was maybe retarding the ignition with the bad MAF so there was excess fuel being input and the ECU needed to adapt to the new MAF values.

I only returned from a short test drive after discovering the idle was settling to its normal 680 rpm. In advanced settings of the dash I confirmed there was no wandering with the digital read out in real time. System voltage fluctuated at idle between 14.5 to 14.8 V. Operating coolant (88 C) and oil (100 C) all look ok. The Error Codes sub menu very very briefly showed a code which immediately went away. As I drove, I kept scrolling the menu to periodically check voltage, fuel consumption, oil/coolant temps and any new codes from the DTC. No codes.

My question, what is the general time for the ECU to go over MAF and MAP adaptations? Do I need to reset those manually by either using an F-series compatible version of INPA (Rheingold someday...) or pull the negative battery terminal loose and let the car sit for 15 minutes or so? Also there is just the ever so slight lightning quick periodic hesitation at low/partial throttle, but the engine is an absolute monster at full throttle/sport mode since this new MAF was installed.

Thanks for any insight!

[328 Power 04]

Hmm, a lot of the work you are describing is mostly for petrol/gasoline cars.

You are talking about the tri-turbo N57, right? The engine control on the diesels is completely different. A bad idle on diesel is very concerning for a fueling issue.

Pulling grounds does nothing for adaptations.

[DRTE30]

Yes, this is the tri-turbo N57 diesel. I forgot to mention that when I first suspected the MAF, I was actually at the BMW dealership having the air con system refreshed. They had extra time so I asked the mechanic to throw his laptop on the car to see if there were any fault codes present. He said there was nothing stored anywhere. A few days later and the cold start idle was rough as described above. If your comment regarding fueling issues is true, well, the RP Injectors need to be serviced/replaced every 100,000. A massive pain...but maybe I'll start tooling up for that project to tackle this fall.

[328 Power 04]

Do you have access to a good diag system? I would log a few of the sensors, fuel pressure request and actual fuel pressure, injector balance, lambda, air flow, charge pressure, temperatures, etc.

If you can see inside the intake manifold for very bad buildup, it may reveal some things.


Does this car have a remap/tune?

[DRTE30]

I recently found out that I can configure INPA to work with F-series chassis, so I am in the process of getting that in order on my BMW-specific laptop. I really want to watch adaptations in real-time of your aforementioned sensors list. Also been toying with the idea of getting an Autel (or derivative like an Oto Fix which uses Autel OS). ...and people are successfully getting Rheingold to run with XP Service Pack 3, so I need to look into that as well. When I pulled the MAP, there was carbon build up but nothing nearly as bad as I've seen on videos where the person needs to pull the intake manifold and AGR valve to clean everything. On the tip of the MAP sensor, I would say the carbon was about 1/2 a mm to 1 mm thick in deposits.

After sitting overnight start up this morning had some stuttering, but not nearly as bad as with the old MAF sensor. I believe 680 rpm is the stock idle and the car would dip to around 660 then go back up. With the A/C on and putting the engine under a bit of load, there was more stuttering than with it off. Voltage stayed pretty constant around 14.1V. However, I can see the interior lights wane in brightness during the stuttering. Not sure if that is relevant or simply a byproduct of the dipping rpm.

[328 Power 04]

You can run INPA and ISTA on modern windows, you don't need old stuff for this. Not sure where the recommendation for Win XP comes. It's absolutely ancient and will give you more issues.

And yes, INPA works even with 2022 cars, but the data is not out there publicly.

You just need an ENET cable and a good windows laptop with an Ethernet port.

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Is there a remap/tune on this car?


I have seen so many of these horrible diesel remaps where they disable hundreds of error codes, which will never show up when there's an error. So your engine can be on fire, and no errors...

[DRTE30]

There is no remap or tune. The car is completely stock and was running perfectly fine for the last 80,000 Km or so! No guide debris in the oil pan, no oil leaks...nothing. I know a few guys out here who have blown their M550d's and M5's with bad piggy back systems from AC Schnitzer.

Thanks again for your insight and I know that without some screenshots of data, diagnosis is hit and miss. I had INPA working completely fine with XP and was able to work on my old 4.8is and 540i M-Sport without issues. Since I bothered to look, F series are now supported, so I am in the process of trying to do a clean install of Mike's Easy BMW Tools, just waiting for the que to start downloading. The K+DCAN cable I have worked in the past without issue as well.

[328 Power 04]

Basically, this is an ENET car, it supports CAN because of legal requirements (for emissions stations), but you can have so much more use if you use the right tools for the job. For example, an ENET cable would easily allow remote diagnosis/coding/programming as needed, as well as fast data rate logging.
Yes, basic diagnosis will work over the slower CAN, but it's not the ideal tool.

[DRTE30]

Small update and general question regarding INPA literature.

Long story short, I have INPA running and was looking at (Vehicle Management> Service Functions> Service Functions> Power Train> Digital Diesel Electronics> Reset Adaptations> FUB-FUB-FB-130006-A08 - Reset Adaptations - V.11) under my VIN number for possible clues while I wait for my ENET cable to show up this weekend. Because I replaced the Hot-Film Mass Air Flow Sensor (13627804150) suspecting the sensor had reached its life, this sensor is also tied into the EGR/AGR (11618570791) and primarily the Intake Air Sensor (13628519445) followed by the Differential Pressure Sensor (13622805758) which sits on the turbo side of the block. All controlled by the DDE.

Secondly, there is no mention of the Charge-air Pressure Sensor aka: MAP sensor (13628514488) causing cold start issues other than it either works or it doesn't, putting the engine in limp mode and maybe...the throttle body plate is gummed up causing a poor seal and talks to the EGR/AGR valve or the Throttle (13547810752) electrical portion is failing, which causes limp mode.

Thirdly, there IS an adaptation procedure to the replacement of any one or all of the sensors under the DDE. However this adaptation requires (from what I found on ISTA) that the car meet the following requirements to conduct a full reset of the DDE and is not done by ISTA itself (correct me if I am wrong, please):
*Engine Speed 1700 - 3000 RPM
*Charging Pressure 1100 - 2800 mBar
*Speed 90 - 160 km/h
*Intake temp difference less than 2 C
*Delay period 3 seconds

My questions are: What does the 'delay period 3 seconds mean'? How long am I to drive the car on the highway until the DDE logs the new adaptation? My first inclination is pull over at an exit on the highway, turn the car off, turn aux power off, unplug the harness to the Hot-Film sensor, wait 15 minutes or so, plug it in and begin driving immediately at the required speed and RPM. This is something I can do in the mean time while I wait for my ENET cable to arrive and see if the situation improves.

[DRTE30]

Update with data: ISTA+ and ENET cable setup and communicating with the car. The two attached screen caps show possible issues leading to the lumpy idle during cold start.

Another maybe relevant observation...and I can be making this observation for the first time during an engine start but I never recall this occurring, the top most turbo located on the passenger side of the block has an actuator on top of it which rotates aprox 45 degrees and has a rod on this actuator that disappears out of site to adjust the exhaust gasses entering the second turbo in series. Upon start up, this actuator was 'searching' i.e. moving back and fourth for a good minute to minute and a half then finally stopped with that actuator at the upper most position of travel.

S0398 - Battery Faulty or Worn Out. Tomorrow I'll verify the age of the battery visually, as well as run ABL Energy Diagnosis via ISTA

25F500 - Intake Air Sensor Signal Open or Short Circuit to Positive. Verify the plug to the MAF sensor is good and plugged in; visual inspection. Check the harness for damage. Check the MAF for improper resistance and continuity

28D600 - Air Mass Flow Sensor Signal Open or Short to Positive/Ground. I just replaced this with a new unit. Delete adaptations via ISTA: Vehicle Management > Service Function > Power train > Digital Diesel Electronics > Adaptations > Air Mass Flow Sensor > ABL Mass Meter > #1 Reset Adaptations > Exit the service function and switch off ignition for 4 minutes

292100 - Charge Pressure Actuator; High Pressure Compressor. This is the wandering actuator I noticed tonight for the first time. Either the turbo took a dive, or the actuator is faulty, or the actuator is getting a conflicting signal from the Hot-Film Mass Airflow sensor *reset adaptations* or the MAP sensor being faulty, or the intake air sensor.

29EB00 - Exhaust Gas Recirculator *EGR/AGR Valve* Cooling, Plausibility. Check a bunch of stuff regarding exhaust gas temps and vacuum leaks.

801C60 - ZGM: No FlexRay Initialization. Test Plan via ISTA

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[328 Power 04]

Codes that have an S and the number are not codes from the car. ISTA makes them up based on the data it gets from the car. Basically it saw that the battery age is past a certain threshold, so it will make up that code. It doesn't actually have much to do with battery wear, except for a calculated model.

The others, you'd have to see when they came up, and if old stored errors from someone disconnecting a sensor, etc.. Use the freeze frame data. You may have to clear and start fresh, just in case.

[DRTE30]

This morning I cleared and started fresh as well as reset the adaptations for the Hot-Film Mass Airflow Sensor. Unbeknownst that my version of ISTA+, 4.10.15, resets all adaptations under the DME. Went for a drive and there was a hint of stumbling under load at low rpm, but overall smoother power delivery. Came back home and did a few chores. Then checked again for codes. This time there are only three instead of six. So the HFMAF and related MAP/MAF codes are now gone. Sweet.

Additional tests:
ABL Power Management, battery.
- Honestly I am new to this software and I am not sure what to make of the data. Visually, the battery is an OEM unit, but there is no date stamp. So all I can do is go off of the data provided in this post. Thoughts?

ABL Charging Pressure Actuator.
- This is an interesting one because I was able to conduct a test on the turbo actuator to check for failure. The actuator looks to be in proper working order, as shown in the attached pictures. The theoretical to actual is off by 1.5%, whether this is a fail I do not know. The position sensor of the actuator is off by 0.3%.

ABL Exhaust Counter Pressure.
- I thought if the back pressure is bad, then the Exhaust Gas Pressure Sensor is failing and may be talking to the DDE to do something to the Charging Pressure Actuator when there doesn't need to be any action. I have a new OEM (13627805758) unit on hand I bought pre-emptively in case this was bad. Reading the data on pic related, the values look to be pretty low. From idle to 2000 RPM, the pressure is 2 - 4 times lower than the max allowable.

Does the Exhaust Counter Pressure Sensor and Charging Air Pressure Sensor tie in together? A biproduct of too much pressure is excessive heat, yet the temp sensor located within the intercooler/charge cooler does not store a fault for being too warm, nor does the coolant and oil temps look abnormal. There are no temp sensors located around or on any of the three turbos and the Charge Air Actuator does not sample temperature. There are only two scenarios for this BMW code 292100; the actuator is bad (which I don't believe) or exhaust temps are too high.

Any avenues I should explore in further detail?

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Attachment 705927
Attachment 705928
Attachment 705929

[328 Power 04]

So, what were the codes left??

You are deviating a bit. Battery doesn't matter so much at the moment. It's original to the car; when you feel like it, change it out.

Since you have a stumble, you need to check injector balance and see if it's one particular cylinder giving you trouble.
Air quantity deviations (lets say due to too much turbo request) or even increased exhaust backpressure will not cause stumbles and misfires.


You may need to dig in under the hood too not just from the computer.

[DRTE30]

The codes left (which I thought were attached via jpg in my last post) are as follows:

S0398 - Battery related
801C60 - Battery related

292100 - Charging pressure actuator, see picture.

29EB00 - Exhaust-gas re-circulation cooling, plausibility: EGR cooler bypass flap or cooler efficiency too low

I think the battery thing is in part my own personal mental block, as some of my novice mechanical background is from diagnosing old Chevy and Ford V8's, where a weak battery can and will cause all sorts of issues and generally something to rectify first unless the problem is obvious.

Charging Pressure Actuator.jpg
65BD6515-B660-436B-A394-D07A17CF8D7B.jpgFCF14B06-DEE8-4E4E-A9CA-68ED5B59074E.jpg

[DRTE30]

The Goose Chace continues. This time with a bit more focus, I promise. The code 292100 checks out ok via the ABL after running the test with the engine on and at operating temperature of the coolant and oil. More notably, I believe the EGR/AGR unit is faulty. Anyone remember the MASSIVE BMW recall on the EGR/AGR causing cars to catch on fire when failing? Affects millions of cars... more on this in a minute.

The 29EB00 fault code was back this evening when I had more time to prod around the engine bay with my multimeter. The Exhaust Temperature Sensor aft the EGR checked out ok with my multimeter, and for fun will check again on a cold engine in the morning. The ABL Bypass Flap, EGR Cooler test was a fail. I performed the standard and extended tests; both failed. Next I visually inspected the Exhaust Cooler (11717823210) which has the EGR/AGR (11717810871) mounted on the top side of it. The OEM sticker on the exhaust cooler is a NLA part number (782321008) where this part number is scrubbed from places like Realoem. Also the exhaust cooler has a manufacture date of 17th October 2010...where my car is a March 2013 build. So the summary of this last paragraph makes the exhaust cooler and EGR/AGR suspect of failure. Let's continue.

For fun about six months ago I had a blow out on the side of the oil filter housing located on the driver-side of the block. This manufacturing abomination is comprised of four layers of composite and aluminum and utilizes five different sets of miss-shaped custom o-rings. I repaired that due to a pin sized hole that developed. After performing the bleed procedure a few times once the repairs were made, I took the car into the local BMW shop and had them do a pressurized test of the coolant system. All was ok. Fast forward to tonight and I check the coolant level and it's down about 500 mL! Unless I physically check the inside of the exhaust cooler with an oscilloscope I am kind of stabbing in the dark. However, the whole point of the EGR/AGR system failing in BMW N47 and N57 diesel engines is that holes in the coolant lines that run through this exhaust cooling system do NOT show during a pressurized test nor are visible by observation alone; the observer must stick a camera in there and physically look for problems. The fact the coolant is low all of a sudden, the engine is stumbling upon start up and randomly at low rpm, under load and the obvious code for this system makes a failure of this part highly suspect.

At this point, I need to reach out to the BMW service center ASAP and talk with the service manager regarding the Exhaust Cooler and EGR/AGR recall and get an inspection.

9A8599C7-DD6A-44D0-B0D8-17EFF66A9EA4.jpg

[DRTE30]

Small update: Went to the local BMW dealership this morning. Inquired about the EGR/AGR recall. The shop technician asked me a few questions about driveability and symptoms that lead me to believe there is a problem. Standard, "car is drinking coolant like an alcoholic", "cold start shaking", "low rpm stumble" and that I had a cooling system test performed recently with zero visual leaks even though the coolant is low.

I asked him about the material of the exhaust cooler and whether it being plastic or aluminum made any difference. He said the recall includes the M550d and that the material is irrelevant. I didn't get a print out of this recall, but I will on Thursday evening when I pick up the car then scan the document and post it here so everyone can have a copy who is interested in having their car inspected as the inspection is free.

[328 Power 04]

The codes left (which I thought were attached via jpg in my last post) are as follows:

S0398 - Battery related
801C60 - Battery related

292100 - Charging pressure actuator, see picture.

I think the battery thing is in part my own personal mental block, as some of my novice mechanical background is from diagnosing old Chevy and Ford V8's, where a weak battery can and will cause all sorts of issues and generally something to rectify first unless the problem

You're on a good roll to get the EGR cooler taken care of, even if turns out to not be the cause of the shaking. I'm surprised that car escaped being serviced for that.


On to the issue of the battery..

Again, code "S0398 - Battery related" is not given by the car. The car is not throwing battery errors. That code is applied in by ISTA just by going by the reading of the last time the battery was registered.

Code "801C60 - Battery related" is not battery related at all. This is a code in the FEM module for a one time loss of flexray sync. It's inconsequential. You can just sync Flexray with ISTA (look through the service functions in Gateway drop down). Still, this is a completely inconsequential code and has nothing to do with battery.

My bet is that your car is always at 13.8-14.8V (or over 13.0V) while running, so it's a hard stretch to ever blame voltage for the current issues, unless your alternator is dead.

[DRTE30]

This thread is meandering a bit. Hopefully some good info for anyone in the future.

You're on a good roll to get the EGR cooler taken care of, even if turns out to not be the cause of the shaking. I'm surprised that car escaped being serviced for that.


My bet is that your car is always at 13.8-14.8V (or over 13.0V) while running, so it's a hard stretch to ever blame voltage for the current issues, unless your alternator is dead.

You are right with the voltage. When I have the "hidden" menu unlocked and driving, battery voltage varies from around there and along with your emphasis, I am not chasing the battery issue anymore.

The EGR system: BMW just called me about 45 minutes ago to tell me that in fact the EGR is leaking inside and the entire system will be replaced under the recall. SO, this is rather big news for a few reasons:
1) Here in Europe and on European forums, owners insist this recall only affected certain models (which it does) and certain engines) which it does AND ONLY those who had a ?plastic? EGR. Could be a translation issue, I digress though: I don't speak or read the best German.
2) The recall now encompasses the European M550d F10 and F11 models pre/post facelift
3) This same replacement EGR/AGR part number is also found on the 1 (F20 & F21) and 2 (F22) series which is not listed in the recall, but the engines in those chassis may have faulty EGR's. This is entirely up to the discretion of BMW and how much you mentally fluff the service manager at your local dealership. This is quite easy to prove because the original EGR/AGR will have the OEM sticker and bar code on the front of the part and only involves a little looking and bending to get a clear picture of the part number and date on the sticker. Use that information to press your service manager as you will.

I will be picking up the car in the morning. They do not have the replacement EGR/AGR in stock and by the looks of it, will need to sit tight on while one is procured. I'll get something tangible in writing and update this thread with the scanned document.

[DRTE30]

Update:

After waiting for the EGR/AGR to show up on back order, I picked up the car this morning from the local BMW work shop. All is well on that front and there is no more coolant leak. Likewise, the dealership submitted all the paperwork along with my information regarding the recall. So, onto the next new issue.

BMW Code 292100 - "Charging pressure actuator, high pressure compressor (variable turbine geometry) Electrical or mechanical defect or excess temperature in charging pressure actuator"

I performed the associated ABL via ISTA and there is a 100% failure of the actuator of the high pressure compressor. This is verified via driving performance, physically looking at the part in question and via software. Movement of the actuator needs to be 15 mm, mine is maybe 3 or 4 mm. Several posts up, there is an exploded picture from Realoem of the turbo system. The turbo in question is #1. I can pick up a refurbished OEM unit for about $750, but before I head down that road and replace this myself, is there a possibility to basically rebuild the actuator motor built onto the turbo? Any tutorials? Unfortunately, these actuators are technically non-replaceable via the TIS, but certainly someone somewhere has got the actuator moving again.

[EduBC]

Hi. I have a december 2012 m550d, with exactly the same problem. Changed (due to minor rear damage) dpf, and both pre and post catalityc O2 sensors, changed intake manifold with new OEM one (better price then to refurbish it :P ) , no errors for my injectors or maf/map sensors on ista+, and i cannot see why turbo will impact idle, as they are not running at idle.
Thinking of changing maf with new one soon, as i have 220k km..
Also i just got in sept 2023 new egr cooler changed at dealership (new bmw recall), as other egr recalls were already done, both egr and cooler.
So, any updates from you?