N47 normal EGR operation?

AlexDj · 10-04-2023, 01:41 PM

BMW F31 N47 318D (2013)

I have a DPF problem that's driving me nuts for the past few months, seems I've finally found the issue after numerous visits to the various mechanics and tons of money wasted. That is, I think I found the problem but would really appreciate a second opinion from you guys.

So the long story short, car won't regenerate DPF properly, after forced regen it goes from 0% to 70% clogged in like 10km and stays there for weeks. During forced regen jumps from one percentage to another and back like 10 times, all sorts of weird stuff. I've changed sensors, injector tests, cleaned the DPF which turned out not to be clogged at all and so forth.

Anyway, the EGR was changed about a year ago during regular service, diagnostic showed it was jammed, the replacement part was Pierburg.
The car now has no errors or codes, all clean, however if this EGR operation is faulty, and I believe it is, then it seems the electronics in it is broken. Or, the DDE is (really hope not).

I have removed the plastic cover from the EGR so that I can see the lever, it's moving freely. Tested operation with ISTA, test was good. But with the cover off and engine running this is what I noticed:

Engine is warm to operating temperature, it's 24 celsius outside, engine is running on idle the whole time.

1. After startup EGR moves to, let's say half open (which I believe it should do). Backpressure (DPF exaust pressure sensor) shows 5 hPa, perfect.

2. After about a minute the EGR lever suddenly goes back to the position where it is in it's passive state as if the power was cut to it (as if the engine is off) which is closed (blocks exaust gasses) At this point Backpressure jumps to about 30 hPa.

If I press the accelerator pedal to rev it up to over 2000rpm the EGR lever jumps back to half open (to position number 1 above). Stays there for about a minute and goes back to closed. It will stay closed forever unless I rev the engine up a bit. Also it wont go back to open every time I rev it up, let's say 1 in 5 it stays closed.

So the question is, is this normal, for EGR to just close like that out of the blue, with engine idling the whole time? I would think not, but there are no codes and the EGR is relatively new and considering the amount of money I spent for nothing I'm kinda hesitant to just go and buy another one.

If this is not normal, does anyone know if the EGR itself has some kind of electronics inside that interprets a signal and then actuates the lever or is DDE directly actuating the lever?

Watsey · 10-04-2023, 04:38 PM

If you have remappers in Serbia that can code-out the EGR cycle in the ECU (coded to 100% closed 100% of the time) that's what I'd do.Then just disconnect the wiring harness from the EGR altogether.

Plus, buy the appropriate blanking plate (ebay) and install it at the junction where the outlet of the EGR valve joins the inlet manifold. It's an easy job.

It's also a good idea to remove / inspect / clean the MAF and MAP sensors and. if you can, partially disassemble the inlet manifold so that you can inspect it inside for carbon deposits. If it's heavily fouled you can assume that it and the inlet ports will need cleaning.

EGR is the bane of diesel engines.

AlexDj · 10-05-2023, 04:07 AM

Thanks Watsey.

MAP and MAF were replaced with genuine parts but didn't make any difference. When they removed the MAP they found out the intake was heavily loaded with deposits so they took it off and cleaned it. They showed me the pile of junk they removed, it was incredible, they said about 70% of the intake volume was carbon. This was a few months ago so it should be fine now. They did not clean the inlet ports on the head, I know it's done with walnut blasting but it's going to be tricky to find someone here for that, I'll ask around.

The state doesn't care much about emissions here, so usually on the first sign of DPF problems everyone here just deletes it, it costs just 150 euro for a DPF removal, coding and EGR coding, the whole package. However I would like to keep the car stock as much as possible, I don't mind spending a few bucks but the only thing left now to do is to try a new EGR, if that fails then a new DPF (1740e genuine) and considering the cars value that just doesn't make any sense.

Now, you mentioned just the EGR coding, I know EGR is essential in the DPF regeneration, do you think if I code out the EGR the DPF can remain healthy and do the regenerations with no problems? If the DPF can operate normally with a coded EGR I would be happy to code out the EGR.

jinjur · 10-05-2023, 05:33 AM

Hey Alex,

I am by no means an expert, many more on here will deffo hold that title but I am interested in your journey as I am having not too dissimilar issues but my journey is very different (different engine too). I will be doing my own post which I will link here eventually in case we find common issue.

My common issue is a quick DPF fill up after successful (forced) regen and seemingly continuous regens in normal driving.

My DPF is flagged as nearing end of life (by BMW's mileage reckoning) and has like 50g of ash content. I am also struggling with a high back pressure differential tho.

In terms of what you are seeing in the EGR valve itself, I see the same and I don't think its wrong tbh. Mine was replaced as part of the huge BMW recall with the cooler and it behaves the same. I don't think the EGR should be opening at idle. When I rev mine it does open and then shut. I have seen similar videos online of this operation with no mention of it being wrong.

I don't see any mention of mileage on your car?

J

AlexDj · 10-05-2023, 07:43 AM

Hey Jinjur, thanks for the reply.

As yourself I'm not a mechanic by a long shot, just generally understand how cars work thanks to having a great dad when I was a kid.

My car is a 2013 F31 318d with a N47 engine, has 240.000km on the clock.

It does sound we have pretty much the same issue. The car is high mileage, however I have good reasons to believe the problem is not tied to the mileage. Firstly, this started all of the sudden, it wasn't like it got worse over time with the regenerations. Secondly, a friend of mine has a 2012 520d with 380.000km on the clock, never had an issue with the DPF over the last 8 years. I've also read, as you may have, that people report driving with the factory DPF for 400.000km with no issues, BMW in general seems to have much less problems with DPF comparing to other brands.

I'll try to describe the regeneration behavior more closely.

When I do diagnostics, DPF is around 75% clogged, somewhere around 45g soot. You can remember this as it's "default" state. Sometimes its about 70%, sometimes about 80%, that is when it pops drivetrain error.

I had the DPF cleaned, shop said on the table it was 9% clogged when I dropped it off, 3% clogged when they were done with it, so the DPF wasn't actually clogged at all, I got a printed report that comes out of the machine and the before/after pictures, it's also a very reputable shop, they were even on a TV show. Now, when they fit it back after being cleaned and adaptations and settings reset, it showed 62% clogged (and I know it's clean as a whistle because the shop just cleaned it)... And it goes back to it's normal ~75% in a few minutes of driving, then just sits there for weeks/months, like it's the car default measurement.

On normal driving, the car is in continuous regen mode, as far as I can tell, "regeneration requested" is always on in diagnostics. By just driving it around it starts regen, then stops depending on the driving conditions, however the soot or the clogged percentage does not move at all, exhaust temperature reaches about 500c at the highest. Now, when I request a forced regen I go to the highway and temperatures reach 600c and then the soot starts coming down, but... So the soot and clogged percentage starts coming down, but it has a habit of dropping to let's say 40% clogged, then jump to 50%, stays there for a few seconds and then drops down to 40%. If I drive long enough (about 30 minutes) it eventually drops to 0% and says regeneration complete. But right after that it starts climbing up, and it goes back to ~70% clogged in literally 10-15 minutes of driving.

So, it's driving me nuts. Mechanics are all like - get a new DPF or just pull it out. On the other hand it's clear that the DPF is not actually clogged, sensor live data is good, injectors are good, no faults in the memory.

Only two things I can think of right now are either that EGR thing, because on idle backpressure is 5hPa, which is great, but when the EGR abruptly closes it goes to 30hPa which is very much not good for idle RPM and I think DDE is actually taking that very same measurement to calculate DPF restriction, that's why it's ~70% all the time. The other thing is a bugged DDE computer and, well I hope not.

I think EGR should be partially or fully open on idle when engine is warm and allow exhaust gasses back to the intake, it should be closed only when the engine is cold, on startups and when under acceleration (engine needs power) but I may have misunderstood this.

jinjur · 10-05-2023, 03:03 PM

I rambled bro

https://f30.bimmerpost.com/forums/sh...9#post30546209

ViA · 10-07-2023, 06:08 AM

Pistonrings defect?

Watsey · 10-07-2023, 02:37 PM

Quote:

Originally Posted by AlexDj

Now, you mentioned just the EGR coding, I know EGR is essential in the DPF regeneration, do you think if I code out the EGR the DPF can remain healthy and do the regenerations with no problems? If the DPF can operate normally with a coded EGR I would be happy to code out the EGR.

As far as I know the EGR's only purpose is to recirculate a proportion of the exhaust gases into the inlet manifold, controlled by the ECU and only under low rpm / low fuelling conditions, as a means of reducing the production of NOX.

The DPF burns soot to reduce it to ash, and does this by way of additional fuel into the exhaust just ahead of the DPF. Temperatures increase to (from memory) around 800C. As far as I know this process is completely independent of the EGR.

The ECU should not adjust fuelling just because the EGR is always closed. The remappers that I've spoken with say that all they do is code the EGR cycle to "permanently closed" and that the fuelling map remains unaffected.

Given your inlet manifold was so clogged by carbon I'd seriously consider having the inlet ports walnut blasted. The IM on my car had a layer of soot/sludge 2-3mm thick (~85,000 miles) and although the inlet ports weren't severely restricted they had significant coking.

If you get the EGR coded closed, blank the EGR/IM junction, and have the inlet ports blasted you can then remove the entire inlet tract as a potential cause of your DPF problems.

AlexDj · 10-19-2023, 02:25 PM

Thanks Watsey. I've decided to get the thing out, I've spent too much money and time trying to fix this, I think it's time to admit the DPF is probably just dead. I did buy a new EGR from the dealer, made no change. Haven't really watched what it does, didn't open it, doesn't even matter at this point. The car is scheduled next week to have the DPF removed and EGR coded to closed, they say they will leave the cat inside, just remove the DPF and code it out along with the EGR. I really didn't want to do this, but I have no other options, and since they don't check for DPF or exhaust gasses here there not much of a point dropping a 2k part in a 8k car.

I found a shop that does walnut blasting so I'm doing that next week as well.

Watsey · 10-20-2023, 01:08 PM

Quote:

Originally Posted by AlexDj

Thanks Watsey. I've decided to get the thing out, I've spent too much money and time trying to fix this, I think it's time to admit the DPF is probably just dead. I did buy a new EGR from the dealer, made no change. Haven't really watched what it does, didn't open it, doesn't even matter at this point. The car is scheduled next week to have the DPF removed and EGR coded to closed, they say they will leave the cat inside, just remove the DPF and code it out along with the EGR. I really didn't want to do this, but I have no other options, and since they don't check for DPF or exhaust gasses here there not much of a point dropping a 2k part in a 8k car.

I found a shop that does walnut blasting so I'm doing that next week as well.

10-04-2023, 01:41 PM	#1
AlexDj New Member 0 Rep 11 Posts Drives: BMW F31 318D Join Date: Aug 2020 Location: Serbia iTrader: (0)	N47 normal EGR operation? BMW F31 N47 318D (2013) I have a DPF problem that's driving me nuts for the past few months, seems I've finally found the issue after numerous visits to the various mechanics and tons of money wasted. That is, I think I found the problem but would really appreciate a second opinion from you guys. So the long story short, car won't regenerate DPF properly, after forced regen it goes from 0% to 70% clogged in like 10km and stays there for weeks. During forced regen jumps from one percentage to another and back like 10 times, all sorts of weird stuff. I've changed sensors, injector tests, cleaned the DPF which turned out not to be clogged at all and so forth. Anyway, the EGR was changed about a year ago during regular service, diagnostic showed it was jammed, the replacement part was Pierburg. The car now has no errors or codes, all clean, however if this EGR operation is faulty, and I believe it is, then it seems the electronics in it is broken. Or, the DDE is (really hope not). I have removed the plastic cover from the EGR so that I can see the lever, it's moving freely. Tested operation with ISTA, test was good. But with the cover off and engine running this is what I noticed: Engine is warm to operating temperature, it's 24 celsius outside, engine is running on idle the whole time. 1. After startup EGR moves to, let's say half open (which I believe it should do). Backpressure (DPF exaust pressure sensor) shows 5 hPa, perfect. 2. After about a minute the EGR lever suddenly goes back to the position where it is in it's passive state as if the power was cut to it (as if the engine is off) which is closed (blocks exaust gasses) At this point Backpressure jumps to about 30 hPa. If I press the accelerator pedal to rev it up to over 2000rpm the EGR lever jumps back to half open (to position number 1 above). Stays there for about a minute and goes back to closed. It will stay closed forever unless I rev the engine up a bit. Also it wont go back to open every time I rev it up, let's say 1 in 5 it stays closed. So the question is, is this normal, for EGR to just close like that out of the blue, with engine idling the whole time? I would think not, but there are no codes and the EGR is relatively new and considering the amount of money I spent for nothing I'm kinda hesitant to just go and buy another one. If this is not normal, does anyone know if the EGR itself has some kind of electronics inside that interprets a signal and then actuates the lever or is DDE directly actuating the lever?
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10-04-2023, 04:38 PM	#2
Watsey Major General 6399 Rep 8,489 Posts Drives: F31 330D sDrive M Sport Join Date: Jun 2015 Location: On sabbatical. iTrader: (1)	If you have remappers in Serbia that can code-out the EGR cycle in the ECU (coded to 100% closed 100% of the time) that's what I'd do.Then just disconnect the wiring harness from the EGR altogether. Plus, buy the appropriate blanking plate (ebay) and install it at the junction where the outlet of the EGR valve joins the inlet manifold. It's an easy job. It's also a good idea to remove / inspect / clean the MAF and MAP sensors and. if you can, partially disassemble the inlet manifold so that you can inspect it inside for carbon deposits. If it's heavily fouled you can assume that it and the inlet ports will need cleaning. EGR is the bane of diesel engines. __________________ Current : F31 330sD, remapped, Ohlins Road & Track, Millway camber plates, Quaife LSD, Stoptech brakes + Pagid RSL1 pads all round, Weichers front strut brace, Eibach front & rear anti-roll bars, Michelin MP4S. Last edited by Watsey; 10-07-2023 at 02:22 PM.. Reason: typo - I hate autocorrect...
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10-05-2023, 04:07 AM	#3
AlexDj New Member 0 Rep 11 Posts Drives: BMW F31 318D Join Date: Aug 2020 Location: Serbia iTrader: (0)	Thanks Watsey. MAP and MAF were replaced with genuine parts but didn't make any difference. When they removed the MAP they found out the intake was heavily loaded with deposits so they took it off and cleaned it. They showed me the pile of junk they removed, it was incredible, they said about 70% of the intake volume was carbon. This was a few months ago so it should be fine now. They did not clean the inlet ports on the head, I know it's done with walnut blasting but it's going to be tricky to find someone here for that, I'll ask around. The state doesn't care much about emissions here, so usually on the first sign of DPF problems everyone here just deletes it, it costs just 150 euro for a DPF removal, coding and EGR coding, the whole package. However I would like to keep the car stock as much as possible, I don't mind spending a few bucks but the only thing left now to do is to try a new EGR, if that fails then a new DPF (1740e genuine) and considering the cars value that just doesn't make any sense. Now, you mentioned just the EGR coding, I know EGR is essential in the DPF regeneration, do you think if I code out the EGR the DPF can remain healthy and do the regenerations with no problems? If the DPF can operate normally with a coded EGR I would be happy to code out the EGR.
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10-05-2023, 05:33 AM	#4
jinjur yes....spelt with J's 55 Rep 963 Posts Drives: F31 325D MSport Join Date: Jan 2009 Location: NoRtH eYeLaNd iTrader: (0)	Hey Alex, I am by no means an expert, many more on here will deffo hold that title but I am interested in your journey as I am having not too dissimilar issues but my journey is very different (different engine too). I will be doing my own post which I will link here eventually in case we find common issue. My common issue is a quick DPF fill up after successful (forced) regen and seemingly continuous regens in normal driving. My DPF is flagged as nearing end of life (by BMW's mileage reckoning) and has like 50g of ash content. I am also struggling with a high back pressure differential tho. In terms of what you are seeing in the EGR valve itself, I see the same and I don't think its wrong tbh. Mine was replaced as part of the huge BMW recall with the cooler and it behaves the same. I don't think the EGR should be opening at idle. When I rev mine it does open and then shut. I have seen similar videos online of this operation with no mention of it being wrong. I don't see any mention of mileage on your car? J
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10-05-2023, 07:43 AM	#5
AlexDj New Member 0 Rep 11 Posts Drives: BMW F31 318D Join Date: Aug 2020 Location: Serbia iTrader: (0)	Hey Jinjur, thanks for the reply. As yourself I'm not a mechanic by a long shot, just generally understand how cars work thanks to having a great dad when I was a kid. My car is a 2013 F31 318d with a N47 engine, has 240.000km on the clock. It does sound we have pretty much the same issue. The car is high mileage, however I have good reasons to believe the problem is not tied to the mileage. Firstly, this started all of the sudden, it wasn't like it got worse over time with the regenerations. Secondly, a friend of mine has a 2012 520d with 380.000km on the clock, never had an issue with the DPF over the last 8 years. I've also read, as you may have, that people report driving with the factory DPF for 400.000km with no issues, BMW in general seems to have much less problems with DPF comparing to other brands. I'll try to describe the regeneration behavior more closely. When I do diagnostics, DPF is around 75% clogged, somewhere around 45g soot. You can remember this as it's "default" state. Sometimes its about 70%, sometimes about 80%, that is when it pops drivetrain error. I had the DPF cleaned, shop said on the table it was 9% clogged when I dropped it off, 3% clogged when they were done with it, so the DPF wasn't actually clogged at all, I got a printed report that comes out of the machine and the before/after pictures, it's also a very reputable shop, they were even on a TV show. Now, when they fit it back after being cleaned and adaptations and settings reset, it showed 62% clogged (and I know it's clean as a whistle because the shop just cleaned it)... And it goes back to it's normal ~75% in a few minutes of driving, then just sits there for weeks/months, like it's the car default measurement. On normal driving, the car is in continuous regen mode, as far as I can tell, "regeneration requested" is always on in diagnostics. By just driving it around it starts regen, then stops depending on the driving conditions, however the soot or the clogged percentage does not move at all, exhaust temperature reaches about 500c at the highest. Now, when I request a forced regen I go to the highway and temperatures reach 600c and then the soot starts coming down, but... So the soot and clogged percentage starts coming down, but it has a habit of dropping to let's say 40% clogged, then jump to 50%, stays there for a few seconds and then drops down to 40%. If I drive long enough (about 30 minutes) it eventually drops to 0% and says regeneration complete. But right after that it starts climbing up, and it goes back to ~70% clogged in literally 10-15 minutes of driving. So, it's driving me nuts. Mechanics are all like - get a new DPF or just pull it out. On the other hand it's clear that the DPF is not actually clogged, sensor live data is good, injectors are good, no faults in the memory. Only two things I can think of right now are either that EGR thing, because on idle backpressure is 5hPa, which is great, but when the EGR abruptly closes it goes to 30hPa which is very much not good for idle RPM and I think DDE is actually taking that very same measurement to calculate DPF restriction, that's why it's ~70% all the time. The other thing is a bugged DDE computer and, well I hope not. I think EGR should be partially or fully open on idle when engine is warm and allow exhaust gasses back to the intake, it should be closed only when the engine is cold, on startups and when under acceleration (engine needs power) but I may have misunderstood this. Last edited by AlexDj; 10-05-2023 at 07:54 AM..
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10-05-2023, 03:03 PM	#6
jinjur yes....spelt with J's 55 Rep 963 Posts Drives: F31 325D MSport Join Date: Jan 2009 Location: NoRtH eYeLaNd iTrader: (0)	I rambled bro https://f30.bimmerpost.com/forums/sh...9#post30546209
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10-07-2023, 06:08 AM	#7
ViA New Member 2 Rep 21 Posts Drives: G30, F34, E90 Join Date: Mar 2014 Location: Slovenia iTrader: (0)	Pistonrings defect?
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10-19-2023, 02:25 PM	#9
AlexDj New Member 0 Rep 11 Posts Drives: BMW F31 318D Join Date: Aug 2020 Location: Serbia iTrader: (0)	Thanks Watsey. I've decided to get the thing out, I've spent too much money and time trying to fix this, I think it's time to admit the DPF is probably just dead. I did buy a new EGR from the dealer, made no change. Haven't really watched what it does, didn't open it, doesn't even matter at this point. The car is scheduled next week to have the DPF removed and EGR coded to closed, they say they will leave the cat inside, just remove the DPF and code it out along with the EGR. I really didn't want to do this, but I have no other options, and since they don't check for DPF or exhaust gasses here there not much of a point dropping a 2k part in a 8k car. I found a shop that does walnut blasting so I'm doing that next week as well.
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