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Originally Posted by 135i_vs_
Got the car back after 2+ months today.
Chain of events: Each ">" represents a separate dealership visit
SES LIGHT, REPLACE INJECTOR > SES LIGHT, REPLACE INJECTOR, REPROGRAM DDE > SES LIGHT REPLACE DDE > SES LIGHT, REPROGRAM DDE, REPLACE INJECTOR, REPLACE HPFP > SES LIGHT,REPLACE ENGINE HARNESS > SES LIGHT, CLEAN CYLINDER HEAD OF CARBON BUILD UP, SES LIGHT, REPLACE 6 INJECTORS, SES LIGHT, REPLACE DDE, issue resolved
To make a long story short, it was the DDE causing the SES light for "Zero Volume Adaptation".
What caused the DDE to fail? According to BMW Engineering, faulty Engine Harness was to blame for the DDE electronic failure.
If you see the pattern of the visits, DDE was replaced once before the Engine Harness replacement, however, that new DDE was also damaged by a short circuit due to the engine harness after 1000 miles or so, causing it to fail.
Now that everything is in place, lets see how it goes. 300+ miles and no issues. The car is driving like it should.
So if it is the ENGINE HARNESS causing the DDE failures, shouldn't there be a Technical Service Bulletin from BMW? Is the harness also causing other part(s) to fail?
As you can see, the dealer had to keep throwing parts at the car as per BMW Engineering to finally get to the bottom of this.
Regarding the build up in the intake, intake valves, and cylinder head: This is a result of the electronic EGR functionality. Is there a way around it? Only way would be to "tune it out". The stock setting for the AIR to EGR ratio needs to be modified.
BMW did redesign and reprogram the EGR operation, however there isn't any data yet available if this solved the excessive soot/tar build up.
It's been a long journey for me (5 months) to get this 335D back in my hands fixed. Hopefully this never happens again to me, and if it is happening to you, hopefully I have shed some light on this issue.
I have had BMW loaner cars for this entire experience.
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I've tried to research the carbon buildup issue and found this article in edmunds AutoObserver:
Direct Injection Fouls Some Early Adopters
Apparently gassers which have similar issues theoretically can have less carbon buildup if the electronic controls of the fuel and valves are specifically controlled not to expose the valves and bits to the soot and fuel in direct injected engines:
Quote:
Stephen Russ, technical leader for combustion for Ford’s 2-liter Duratec DI engine, said that similar to GM, engineers have determined the proper injection-timing calibration to help eliminate the carbon deposits. But Russ also said the technology of injection components – particularly the high-pressure solenoid injectors – has quickly matured, meaning excess valve deposits in most DI engines should become a thing of the past as these improved components are incorporated into production.
Tony Chick, principal engineer at European Performance Labs in Stratford, Connecticut, has made a career of repairing and rebuilding high-performance engines from Audi, Porsche AG and BMW, among others and his operation has garnered a reputation among car enthusiasts as a go-to place for cleaning DI engines that have become choked with carbon. Chick thinks the problem for most affected engines can be traced to the breathing system – specifically, the design of its crankcase ventilation and exhaust-gas recirculation components.
All modern gasoline engines return some crankcase and exhaust gases back through the intake manifold in order to help control emissions, but, according to Chick, some exhaust-gas recirculation designs are “dirtier" than others. Some, he said, are less-effective at preventing the passage of tiny bits of oil, carbon and other particulates that eventually get baked onto the intake ports and valves.
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The part about EGR is shared with DI diesel engines, so more exact control of timing and recirculated exhaust gas composition may be where BMW's "fix" with its latest DDE/EGR programming updates is aimed.
PL