[ekuLUKEkul]

Hey, so I have a random stalling issue that has just appeared out of nowehere. If the car is performing a DPF regeneration and you come to a stop the engine starts to splutter and it stalls. I can put it back into park and start it up again with no problem then the car will run fine until the next DPF regen happens.

A few years back the car would do exactly the same stalling process (spluttering and jumping revs then full stall) but only within the first 5 minutes of a journey and only when the car had been stood for 8-12 hours. This turned out to be the EGR valve sticking closed and choking the engine. I have had the EGR deleted and a remap and for the last few years the car has run fault free.

It seems unusual that the same symptoms have appeared again but only when the DPF is regenerating. Has anyone experienced this or something similar? Any ideas.

I have a code reader so I will scan the car and post the findings as soon as I get chance.

Thanks!

[Rich_D]

Without codes, anything else is just guess work unfortunately, get it scanned and see what's there. I would then clear them all and if/when it stalls again re-scan to see what codes have come back.

[ekuLUKEkul]

Update with codes. I just scanned the car and found the following:

4A4F glow control unit
4A3F glow control unit
4A2F glow control unit
4A1F glow control unit
4B1C fuel filter heater, control
4A34 glow plug cylinder 4, control
4A5E glow plug cylinder 2, control

3F03 boost pressure sensor, signal - this one has been present since the remap and I assumed it was due to the remap making the car boost past the usual perameters?

4B1B fuel filter heater, control
4A54 glow plug cylinder 2, activation

I reset them all and went for a drive, during the drive I was sure the DPF was doing a regen and it did the usual when coming to a stop, revs dropped dramatically like it was going to stall, it didn't this time however and picked itself back up to the usual 600rpm idle.

After I got back I scanned again and the following have reappeared:

4A4F glow control unit
4A3F glow control unit
4A2F glow control unit
4A1F glow control unit
4B1C fuel filter heater, control
3F03 boost pressure sensor, signal

Now I have had a lot of those glow control unit codes appearing over the last few years but they have never caused any problems. The car starts fine in the cold (albeit with the glow plug image appearing for a few seconds before it fires on particularly cold days) I also recognise the fuel filter heater code and as mentioned above the boost pressure one that has been present since the remap.

So do these codes help anyone to make a guess? I have read that the glow plugs are important to the DPF function however there seems to be mixed opinions on this?

[Rich_D]

A failed glow plug controller shouldn't cause it to stall, I doubt the fuel filter heater one would either, but you never know.

Boost sensors can get clogged though, mine was full of carbon, easy to access once you remove the engine cover, so may be worth giving it a clean, as well as the MAF, despite no codes.

The only time I've had spluttering and near stalling was when the EGR valve was sticking, try popping the black plastic cover off and see if it's sticking open, you can move it by hand and it should snap back closed.

[ekuLUKEkul]

Yeah I didn't think the glow plug controller would be the fault either tbh, but I read that it supplies heat to the DPF during a regen so thought perhaps? Fuel filter heater I don't even know what that is. But to only happen during the DPF regen seems unlikely.

Boost sensor is an interesting one. I will investigate that, but again, could this be something that only happens when coming to a stop during a DPF regen? It seems so specific I just can't understand what would cause it.

Yeah as I mentioned in my first post, I had the same issue with my EGR sticking. I had it deleted with the remap last year and haven't had a problem since until this new problem. Interestingly the symptoms are identical though. It is the same rev stutter and the car trying to catch itself as it would do when the EGR was sticking. The only difference being that this happens during a DPF regen only when coming to a stop whereas the EGR problem happened only when the car was cold (8-12 hours without turning on cold) and coming to a stop and only within the first 5-10 minutes of driving.

[Rich_D]

Might be worth replacing the glow plug controller to eliminate that, for the N57 you need a Beru GSE108, it can be swapped without removing the inlet manifold, but it's fiddly and you'll swear a lot, trust me LOL.

Boost (MAP) sensor is front right of the engine when you remove the cover, on top of the inlet manifold, 1 bolt holds it in place, pop it out & clean carefully. I used a plastic scraper and then carb cleaner spray, don't poke anything too far down the hole, mine was partially blocked with carbon crap. Whether or not this is causing your issues is unknown, but it can't hurt.

Even though the EGR is mapped out, is it still physically in place? Could it still do something during a regen even though it's not used under normal driving? As you say same kind of symptoms with the hesitation & stuttering, maybe worth asking who mapped it.

[ekuLUKEkul]

Thanks for that. I will change the controller! Maybe I will let someone else do it lol...

Sounds good, did you notice an increase in performance after cleaning the boost sensor? I can't say I have noticed a drop in mine since the map but possibly if it was subtle or gradual.

The EGR is still in place. I guess it is possible it still does something during the regen. My only confusion then would be why it was fine for over a year before starting to act up. But anything is possible! No harm is messaging the garage.

[Rich_D]

It's not too bad, just fiddly as access is tight, photo in this thread >>> https://www.e90post.com/forums/showp...65&postcount=4

After cleaning the boost sensor it wasn't any faster, but felt smoother & more responsive, it also felt better on cold start as it was always a bit lumpy, despite no glow plug issues.

Regarding the EGR, 'assuming' it does do something during the regen, then as it rarely moves it will have got gunked up and caused it to stick again would be the logical conclusion, easy to check that though without having to remove it.

[ekuLUKEkul]

That all makes sense to me! Thanks a lot. I will get to investigating!

[Rich_D]

Any update on this?

[ekuLUKEkul]

No updates, I haven't gotten round to trying anything yet and the car hasn't done the issue again since so I have kind of been forgetting about it! The car is due to go in in early December for MOT's and all that so I was planning on getting some of the stuff checked out then assuming the problem doesn't worsen.