Direct Injection coking on valve stems?

BIMthereRunFlat · 11-26-2021, 06:31 PM

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OK, M340i only been out a couple of years so it's early days yet but I'd previously read so much about issues arising from D.I. leading to the intake valve stems gaining carbon build up from burnt oil deposits, especially on BMW's and Audi's. That was mainly in the 2012-2017 period and manufacturers were starting to look at using both Direct and Port injection to counteract the problem. Can't find much about this specifically corresponding to the M340i so has BMW employed that dual port/direct technique now or is the valve coking issue liable to rear its head once we start getting up in the 50K / four year neck of the woods?

Benjamin_Nicholas · 11-26-2021, 08:13 PM

This is an old issue that hasn't been an issue in quite some time.

BIMthereRunFlat · 11-26-2021, 09:27 PM

Meaning engine design amendments (port + direct) has eliminated this kind of issue so it simply won't happen anymore in the 2020's+ crop of cars? I simply ask because I don't know the answer.

BIMthereRunFlat · 11-26-2021, 09:57 PM

Actually the more I'm reading recent 2021 articles on this subject, the more it suggests the issue is still lurking there and that engine management software is just doing a better job cloaking (not preventing) the problem until it gets really serious when you're still then faced with the walnut blasting delights of yesteryear. Frequent highway miles does seem to help but if you're regularly just putzing around town, beware. When you think about it, why would manufacturers fret because it does tend to take some time to occur, maybe often north of the warranty period (miles or time) so for their dealers it could just be a nice little earner in repairs. Cynical? no I'm not cynical.

11-26-2021, 06:31 PM	#1
BIMthereRunFlat Private 49 Rep 79 Posts Drives: BMW M340i xdrive Join Date: Sep 2021 Location: Wilmington, NC iTrader: (0)	Direct Injection coking on valve stems? Featured on BIMMERPOST.com OK, M340i only been out a couple of years so it's early days yet but I'd previously read so much about issues arising from D.I. leading to the intake valve stems gaining carbon build up from burnt oil deposits, especially on BMW's and Audi's. That was mainly in the 2012-2017 period and manufacturers were starting to look at using both Direct and Port injection to counteract the problem. Can't find much about this specifically corresponding to the M340i so has BMW employed that dual port/direct technique now or is the valve coking issue liable to rear its head once we start getting up in the 50K / four year neck of the woods?
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11-26-2021, 08:13 PM	#2
Benjamin_Nicholas BEAST? ... How dare you. 436 Rep 413 Posts Drives: BMW, Porsche Join Date: Dec 2019 Location: TX iTrader: (0)	This is an old issue that hasn't been an issue in quite some time. __________________ ______________ 1973 Porsche 911S 2023 BMW M550i 2023 BMW X5M 2020 BMW M340i (retired)
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11-26-2021, 09:27 PM	#3
BIMthereRunFlat Private 49 Rep 79 Posts Drives: BMW M340i xdrive Join Date: Sep 2021 Location: Wilmington, NC iTrader: (0)	Meaning engine design amendments (port + direct) has eliminated this kind of issue so it simply won't happen anymore in the 2020's+ crop of cars? I simply ask because I don't know the answer.
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11-26-2021, 09:57 PM	#4
BIMthereRunFlat Private 49 Rep 79 Posts Drives: BMW M340i xdrive Join Date: Sep 2021 Location: Wilmington, NC iTrader: (0)	Actually the more I'm reading recent 2021 articles on this subject, the more it suggests the issue is still lurking there and that engine management software is just doing a better job cloaking (not preventing) the problem until it gets really serious when you're still then faced with the walnut blasting delights of yesteryear. Frequent highway miles does seem to help but if you're regularly just putzing around town, beware. When you think about it, why would manufacturers fret because it does tend to take some time to occur, maybe often north of the warranty period (miles or time) so for their dealers it could just be a nice little earner in repairs. Cynical? no I'm not cynical.
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