M273 unstable idling performance
#51
Junior Member
Thread Starter
You could try temporarily blocking the EGR and the SAP (secondary air pump) to see if that helps.
See this video for EGR on M272 (almost the same for M273) https://www.youtube.com/watch?v=glzJ51Wjs2M
See this video for EGR on M272 (almost the same for M273) https://www.youtube.com/watch?v=glzJ51Wjs2M
#52
It's not my video, just a random one found on the web.
There are blocking plates for sale that block the EGR or SAP, search the web.
Edit: here's one: https://races-shop.com/egr-plugs/265...m272-m273.html
Here's a video that shows the SAP:
There are blocking plates for sale that block the EGR or SAP, search the web.
Edit: here's one: https://races-shop.com/egr-plugs/265...m272-m273.html
Here's a video that shows the SAP:
Last edited by Jaap; 04-13-2024 at 05:55 AM.
#53
Junior Member
Thread Starter
On the link there is only one plate and it has a different form. This one looks to be a correct one: https://milauto.com.ua/ua/product/13441247165/
Both links has only one plate. Does it mean it's enough to cover only one EGR to disable this system?
Also you said to try to disable it temporally. Today I have unplugged both electric plugs (EGR and SAP). But it doesn't help.
In general the valves on that video doesn't look like it could it be on diesel engines. I'm not sure these valves could be a reason for my case.
Both links has only one plate. Does it mean it's enough to cover only one EGR to disable this system?
Also you said to try to disable it temporally. Today I have unplugged both electric plugs (EGR and SAP). But it doesn't help.
In general the valves on that video doesn't look like it could it be on diesel engines. I'm not sure these valves could be a reason for my case.
Last edited by Plato; 04-13-2024 at 10:37 AM.
#54
#59
Junior Member
Thread Starter
Yes I tried to unplug both EGR and SAP wires. Nothing changed.
My next step would be to remove rear OS programmatically. Just cut the part of software and related errors what are in charge of ecology - the main purpose of rear OS. But before I do this I want to give few more tries to this engine. I really want to find the reason.
#60
#61
Junior Member
Thread Starter
#62
did you ever do a conventional compression test ? that would at least cover if each cyl has a chance to do its bit
then give it some real exercise or I forget the miles, check the posts of cooked engine ECUs, capacitors play up and give random spark
then give it some real exercise or I forget the miles, check the posts of cooked engine ECUs, capacitors play up and give random spark
#63
These valves open and close when the engine runs.
And the air can be leaked into the exhaust where the smoke is hard to see.
Last edited by Jaap; 04-14-2024 at 01:54 PM.
#64
Junior Member
Thread Starter
#65
#66
Junior Member
Thread Starter
#67
is there a way to check the CATs efficiency / aging ?
I didn't know - seems the crooks have made them extra fragile on modern cars - it was std on earlier Merc's they'd block up like putting a banana in the exhaust - but now they make them extra fragile so they don't block, but its OK as now the sensors either end will catch out the electronics - a tiny misfire (that every 221 has had due to the fantastic ignition coils) is enough to finish them off
I didn't know - seems the crooks have made them extra fragile on modern cars - it was std on earlier Merc's they'd block up like putting a banana in the exhaust - but now they make them extra fragile so they don't block, but its OK as now the sensors either end will catch out the electronics - a tiny misfire (that every 221 has had due to the fantastic ignition coils) is enough to finish them off
#68
Junior Member
Thread Starter
is there a way to check the CATs efficiency / aging ?
I didn't know - seems the crooks have made them extra fragile on modern cars - it was std on earlier Merc's they'd block up like putting a banana in the exhaust - but now they make them extra fragile so they don't block, but its OK as now the sensors either end will catch out the electronics - a tiny misfire (that every 221 has had due to the fantastic ignition coils) is enough to finish them off
I didn't know - seems the crooks have made them extra fragile on modern cars - it was std on earlier Merc's they'd block up like putting a banana in the exhaust - but now they make them extra fragile so they don't block, but its OK as now the sensors either end will catch out the electronics - a tiny misfire (that every 221 has had due to the fantastic ignition coils) is enough to finish them off
#69
Junior Member
Thread Starter
Still looking for a solution. If someone was facing the same issue please share your experience.
At the moment, before cutting out the sensors programmatically, I am thinking of returning to the point that has already been marked as done - the throttle. In theory, if the tracks on the board (on which the sliders run) are already worn out, the device loses accuracy (resolution). And let's say the rear OS ask ECU - make intake lean, add air. The throttle adds more air than necessary, then the ECU makes intake rich and so in a circle, hence the "sinusoid" or "cyclicality" of floating revs in my case. I marked this point as done because I bought a used throttle. The tracks on it were similar in usage to mine. But thought it couldn't be a coincidence that they were used equally and that the effect should have changed somehow. Now thinking of buying a brand new throttle.
At the moment, before cutting out the sensors programmatically, I am thinking of returning to the point that has already been marked as done - the throttle. In theory, if the tracks on the board (on which the sliders run) are already worn out, the device loses accuracy (resolution). And let's say the rear OS ask ECU - make intake lean, add air. The throttle adds more air than necessary, then the ECU makes intake rich and so in a circle, hence the "sinusoid" or "cyclicality" of floating revs in my case. I marked this point as done because I bought a used throttle. The tracks on it were similar in usage to mine. But thought it couldn't be a coincidence that they were used equally and that the effect should have changed somehow. Now thinking of buying a brand new throttle.
#70
.... I wrote this on a bike forum at the weekend, I wonder if you can glean anything of use from it
rambling possibility driving fuel use...
..... my merc 5.5 V8 and a mate with a CL550 have both experienced the fuel consumption falling off a cliff in the last 18 months, suddenly both are drinking 20% more.... and my R1200GS, its drinking like hell these days too
then another bod on the merc forum popped up saying his was doing the same - he took to a dealer and they gave it the all clear - but when he looked at fuel trims one bank of cyl's is massively different to the other...
And whilst chemistry-physics informs us ethanol infected crap, instead of real petrol has to be in the mix of this decline in mpg, it can't be the only effect - 10% ethanol means what you burn has 6% less energy to push the piston down - but the reformulated water we get today performs much worse than that....
the reason I know a bit about how the BM fuelling behaves, is because my old R1200GS had been going mad for 6 years since an i- level update in 2018 - my 2007 GS was far faster than many - but it was bought first by an old boy and I know the garage that sold it, so it was std - whilst fast, it loved to run rough and stall a lot (the stalling was partly the silly dry car clutch), but the instrument cluster would do somersaults if you tried to ride under 3k rpm and ragging to death in hot weather would cause the power to tail off due to knock after 6k rpm.
when it was sold new it had an i-level update to Jan 2008, and during a dealer service in 2009 I said surely there is a better engine map, it runs like a joke. I was informed “its a BMW Sir, we don't do things like that”.
Role on some 6 years and I find out he was lying through his teeth - after I broke my 335D playing trying to add software to allow me to use a later iDrive knob - the guy said well its so old likely needs an i-level update anyway... Whats that I said... Dealers battled like hell to refuse, but finally did the work and the car came back with its first ever i-level update, going twice as fast, the auto gearbox was vastly better with its new software, some sat nav foibles got fixed, and it had a load of security updates.
All of which meant I found out going back (now) 20 years, BMW have always had a software refresh / update procedure which they review three times a year. And its there for ALL their vehicles (and meant to be just 10 mins of chargeable labour to the customer) - Thus now understanding the poor running on my GS may have been resolved, I started to find out info about my bike. And low an behold I discover the release notes for a mid 2008 i-level update for my GS - of which three addressed running issues applicable to my GS
poor idle stability
changes to cold running enrichment
resolve engine pinging from customer complaints
So in 2018, 10 years after BM should have put it on the bike I got this update - and it all went downhill - slow, horrible with a massive dead midrange and lost all top end grunt. I went back and they reflashed it, but with no change...
I had used a Dynojet PC3 on the old map and had it almost perfect - save that hot weather die back due to knock... But now the bike was a disaster and I couldn't get the PC3 to work no matter what I did - I took it off and it was awful, put it back it was awful - raised a PUMA case with BMW to say you are morons and have written a duff map - PUMA gets the factory tech hero’s to investigate their incompetence and if required authorise (as they can and always have been able to ) that this vehicle can go backwards to the older release, whilst (if they can be bothered) they resolve the software bug in that i-level - they refused to put back the older better map and just reflashed the bike a third time, BUT also reset the vehicle adaptions (which it turns out has always been the std process the dealerships are meant to complete if the engine map is updated - but they NEVER do it) - After this the bike was less bad but still nasty, the midrange hole was mostly gone, and it had its top end grunt back that had gone walkabout for 2 years... And magically the PC3 began to allow me to make changes that made sense - where for 2 years it had just been insanity...
And the reason is that a bike that's adapted to an old map has a load of confused personalised adjustment junk for the old map, that it tries to apply to the new map (but none of it makes sense)... Subsequently I discovered, its all made worse if you have a PC3 on the bike - as it will not adapt ever to the newer map's needs - because the O2 sensors aren't plugged in...
After (I thought) learning all the fun of the fair - I then come across a nuance where my Merc allows a reset of cold weather adaptions and of its std adaptions as two separate functions – And realise maybe my bike runs so horrifically in winter with the cold temp enhancement of the new map, because it’s never adapted correctly due to the PC3 being fitted.
But then trying with and without the PC3 over a winter and getting confused all over again - it now appears a CAT sensor got old and intermittent. And BMW designed it to go mad under this condition deliberately - If one of the GS’ two CAT sensor dies, it deliberately throws the fuelling of the other cyl in massive tail spin and adapts long and short trims to insanity – and the bike transforms in to a lumbering load of recalcitrant gibberish… (you can easily test this by swapping CATS sensors side to side and seeing the exact behaviors swap cylinders) all the while with no engine light to the user, and indeed nothing in its own diagnostic brain either !!!
So back to your K1200 drinking – a clue I believe is in the night rider instructions for the AFXieds – “these need a good signal from the O2 sensors to operate correctly…”
AKA aging CAT sensors on German vehicles allow the engine ECU to find a secret engine map - "drink fuel at all costs"
Oh and just showing the love - the 335D although massively transformed for the better by its i-level update, directly after, I started to notice slip in the transmission when giving it full grief off the line – that was not why I got rid of it – but years later I find out it wasn’t broken - it was a slight of hand BMW, introducing a feature to save the drive line from too much stress – the update brought reduced line pressure to open up clutches under full throttle launches
Wonderful – when these were being used as drag cars and all the world was pushing 900nm through the box with no issues BMW dropped the limit to 500nm from it original 575nm rating – causing the box to attempt self-destruction !!! Got to love the Germans ability to wreck the planet and steal money...
..... my merc 5.5 V8 and a mate with a CL550 have both experienced the fuel consumption falling off a cliff in the last 18 months, suddenly both are drinking 20% more.... and my R1200GS, its drinking like hell these days too
then another bod on the merc forum popped up saying his was doing the same - he took to a dealer and they gave it the all clear - but when he looked at fuel trims one bank of cyl's is massively different to the other...
And whilst chemistry-physics informs us ethanol infected crap, instead of real petrol has to be in the mix of this decline in mpg, it can't be the only effect - 10% ethanol means what you burn has 6% less energy to push the piston down - but the reformulated water we get today performs much worse than that....
the reason I know a bit about how the BM fuelling behaves, is because my old R1200GS had been going mad for 6 years since an i- level update in 2018 - my 2007 GS was far faster than many - but it was bought first by an old boy and I know the garage that sold it, so it was std - whilst fast, it loved to run rough and stall a lot (the stalling was partly the silly dry car clutch), but the instrument cluster would do somersaults if you tried to ride under 3k rpm and ragging to death in hot weather would cause the power to tail off due to knock after 6k rpm.
when it was sold new it had an i-level update to Jan 2008, and during a dealer service in 2009 I said surely there is a better engine map, it runs like a joke. I was informed “its a BMW Sir, we don't do things like that”.
Role on some 6 years and I find out he was lying through his teeth - after I broke my 335D playing trying to add software to allow me to use a later iDrive knob - the guy said well its so old likely needs an i-level update anyway... Whats that I said... Dealers battled like hell to refuse, but finally did the work and the car came back with its first ever i-level update, going twice as fast, the auto gearbox was vastly better with its new software, some sat nav foibles got fixed, and it had a load of security updates.
All of which meant I found out going back (now) 20 years, BMW have always had a software refresh / update procedure which they review three times a year. And its there for ALL their vehicles (and meant to be just 10 mins of chargeable labour to the customer) - Thus now understanding the poor running on my GS may have been resolved, I started to find out info about my bike. And low an behold I discover the release notes for a mid 2008 i-level update for my GS - of which three addressed running issues applicable to my GS
poor idle stability
changes to cold running enrichment
resolve engine pinging from customer complaints
So in 2018, 10 years after BM should have put it on the bike I got this update - and it all went downhill - slow, horrible with a massive dead midrange and lost all top end grunt. I went back and they reflashed it, but with no change...
I had used a Dynojet PC3 on the old map and had it almost perfect - save that hot weather die back due to knock... But now the bike was a disaster and I couldn't get the PC3 to work no matter what I did - I took it off and it was awful, put it back it was awful - raised a PUMA case with BMW to say you are morons and have written a duff map - PUMA gets the factory tech hero’s to investigate their incompetence and if required authorise (as they can and always have been able to ) that this vehicle can go backwards to the older release, whilst (if they can be bothered) they resolve the software bug in that i-level - they refused to put back the older better map and just reflashed the bike a third time, BUT also reset the vehicle adaptions (which it turns out has always been the std process the dealerships are meant to complete if the engine map is updated - but they NEVER do it) - After this the bike was less bad but still nasty, the midrange hole was mostly gone, and it had its top end grunt back that had gone walkabout for 2 years... And magically the PC3 began to allow me to make changes that made sense - where for 2 years it had just been insanity...
And the reason is that a bike that's adapted to an old map has a load of confused personalised adjustment junk for the old map, that it tries to apply to the new map (but none of it makes sense)... Subsequently I discovered, its all made worse if you have a PC3 on the bike - as it will not adapt ever to the newer map's needs - because the O2 sensors aren't plugged in...
After (I thought) learning all the fun of the fair - I then come across a nuance where my Merc allows a reset of cold weather adaptions and of its std adaptions as two separate functions – And realise maybe my bike runs so horrifically in winter with the cold temp enhancement of the new map, because it’s never adapted correctly due to the PC3 being fitted.
But then trying with and without the PC3 over a winter and getting confused all over again - it now appears a CAT sensor got old and intermittent. And BMW designed it to go mad under this condition deliberately - If one of the GS’ two CAT sensor dies, it deliberately throws the fuelling of the other cyl in massive tail spin and adapts long and short trims to insanity – and the bike transforms in to a lumbering load of recalcitrant gibberish… (you can easily test this by swapping CATS sensors side to side and seeing the exact behaviors swap cylinders) all the while with no engine light to the user, and indeed nothing in its own diagnostic brain either !!!
So back to your K1200 drinking – a clue I believe is in the night rider instructions for the AFXieds – “these need a good signal from the O2 sensors to operate correctly…”
AKA aging CAT sensors on German vehicles allow the engine ECU to find a secret engine map - "drink fuel at all costs"
Oh and just showing the love - the 335D although massively transformed for the better by its i-level update, directly after, I started to notice slip in the transmission when giving it full grief off the line – that was not why I got rid of it – but years later I find out it wasn’t broken - it was a slight of hand BMW, introducing a feature to save the drive line from too much stress – the update brought reduced line pressure to open up clutches under full throttle launches
Wonderful – when these were being used as drag cars and all the world was pushing 900nm through the box with no issues BMW dropped the limit to 500nm from it original 575nm rating – causing the box to attempt self-destruction !!! Got to love the Germans ability to wreck the planet and steal money...
#71
Senior Member
Join Date: Jan 2018
Location: Atlanta GA
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2012 E350 Cabriolet now SOLD to my son
Still looking for a solution. If someone was facing the same issue please share your experience.
At the moment, before cutting out the sensors programmatically, I am thinking of returning to the point that has already been marked as done - the throttle. In theory, if the tracks on the board (on which the sliders run) are already worn out, the device loses accuracy (resolution). And let's say the rear OS ask ECU - make intake lean, add air. The throttle adds more air than necessary, then the ECU makes intake rich and so in a circle, hence the "sinusoid" or "cyclicality" of floating revs in my case. I marked this point as done because I bought a used throttle. The tracks on it were similar in usage to mine. But thought it couldn't be a coincidence that they were used equally and that the effect should have changed somehow. Now thinking of buying a brand new throttle.
At the moment, before cutting out the sensors programmatically, I am thinking of returning to the point that has already been marked as done - the throttle. In theory, if the tracks on the board (on which the sliders run) are already worn out, the device loses accuracy (resolution). And let's say the rear OS ask ECU - make intake lean, add air. The throttle adds more air than necessary, then the ECU makes intake rich and so in a circle, hence the "sinusoid" or "cyclicality" of floating revs in my case. I marked this point as done because I bought a used throttle. The tracks on it were similar in usage to mine. But thought it couldn't be a coincidence that they were used equally and that the effect should have changed somehow. Now thinking of buying a brand new throttle.
#72
Junior Member
Thread Starter
Thanks for sharing! OS version could also make sense of course. My one is updated to the newest OS version. However previous had the same issue but on that time the car had LPG installed. I have removed LPG (not mine installation) and updated ECU to the latest OS + reseted all settings to be valid with my VIN. It was done on Mercedes-Benz official dealer store. So might be a reason but very low chance as two version already had the same issue.
Last edited by Plato; 04-15-2024 at 02:07 PM.
#73
Junior Member
Thread Starter
#74
Hi,
I have R500 with same M273 engine. I also suffer from similar issues: a slight misfire at warm idle that goes away with any kind of load (moving gears from N to D is enough). No CE or other issues.
I have read all your troubleshooting steps and wonder whether you have ever checked variable intake manifold linkage?
This is very common issue on both M272 and M273. Linkage gets loose and there are even cases where internal flaps/tumblers dislodge and partially block some of cylinders. It is at least worth taking a look into.
I have R500 with same M273 engine. I also suffer from similar issues: a slight misfire at warm idle that goes away with any kind of load (moving gears from N to D is enough). No CE or other issues.
I have read all your troubleshooting steps and wonder whether you have ever checked variable intake manifold linkage?
This is very common issue on both M272 and M273. Linkage gets loose and there are even cases where internal flaps/tumblers dislodge and partially block some of cylinders. It is at least worth taking a look into.
#75
Thanks for sharing! OS version could also make sense of course. My one is updated to the newest OS version. However previous had the same issue but on that time the car had LPG installed. I have removed LPG (not mine installation) and updated ECU to the latest OS + reset all settings to be valid with my VIN. It was done on Mercedes-Benz official dealer store. So might be a reason but very low chance as two version already had the same issue.
that behavior is why I had gone back to using the PC3 - I reset, did 120 miles took CAT sensors off and then tidied up what wasn't too bad with the PC3 and was happy... but then each winter it was terrible (that later cold weather update of the later map) meant it was so rich in the winter it would bog and chug terribly, when the original map never had an issue in winter... That's when I realised maybe it has winter adaption like the merc... So I put the bike std and rode around all winter adapting and it did improve drastically. But as winter cleared the bike became utterly mental.... and I discovered the CAT voltages on one pop would randomly go stupid - put in a functioning CAT sensor and it improved a lot - but the BM map is still awful and I'm back on the PC3 with CAT sensors off....
However its still a strange one, that one winter of creating adaptions for cold weather has allowed the bike to work OK below 10C, not bad above 14C and brilliant above 25C - BUT I have one temp area where the bike is the chugging madness of enrichment it had been since the Map update, it turns up whenever temps are around 11.5 to 12C the bike can't cope at all !!! but 1C either side its all normal ???? and I now see that is there sensors on or off.
After reading you later posts I was looking for the MAF sensor on parts docs and failed to find it ? but it is the bit the air cleaner fits on
https://www.motor-doctor.co.uk/air-m...21-071-221-171