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carbon build up in the exhaust ports and or fuel injector problems

Discussion in 'E90/E91/E92/E93 (2006-2011)' started by sgilmore, Jan 7, 2013.

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    sgilmore

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    Moderator note: Thread split.

    Since the problem persists you are not "late".
    My car is an automatic so I assume it does not need the hill feature.
    My new "adventure" involves carbon build up in the exhaust ports and or fuel injector problems. They have done the walnut cleaning and replaced one injector; the car runs much better. The plan is to replace three more but they are on back order. Any thoughts/experiences are welcome–thanks!

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    charlson89

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    Depending on the faults in the vehicle they might need to replace all 6 injectors instead of just 3. Also you said they cleaned the exhaust ports, are you sure that wasn't the intake ports? Because cleaning the exhaust ports really wouldn't help with running issues unless it was really bad but then you would have bigger problems if it was getting there. The reason the intake ports get carbon deposits is because of the direct injection fuel system not spraying on the intake valves to help clean carbon deposits. Instead it fires directly into the combustion chamber. This is quite a normal problem with the N54 engine. As for your noise with the brakes is there any way you could record the sound that your hearing would help a lot with diag that noise?
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    sgilmore

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    Thanks for your feedback! Of course it was the intake ports. I will question whether they ought to replace all the injectors. Someone told me "Techron" gas additive would help prevent carbon deposits.
    I will try recording the brake sounds. Then what?
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    charlson89

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    The gas additive will not help the carbon deposits. The N54 engine uses a direct injection system which means is sprays fuel directly into the cylinder. A non direct injection engine sprays fuel on the back of the intake valve thus cleaning the valve at the same time. Carbon deposits on the intake valves are quite common on direct injection engines and add the turbo's are not helping the situation. Any turbo charged engine uses some oil a normal by product from lubricating there bearings. The oil is actually lost into the air stream and ends up burned in the engine or sticking to your intake valves. You can help reduce carbon deposits by doing high engine revs under heavy load. The velocity of the air will break some of the carbon up and be burned. After you get the recording of your brakes let me know and I'll give you my email so I can listen to it. Hope this all helps
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    sgilmore

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    It has, thank you!
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    instantfob

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    robc1976

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    that is one of the things you need and is one of the best OCC on the market. The other problem in the N54 is its very weak PCV valve and there is actually a upgraded one called the RB PCV valve and it works wonders...not saying it will keep your valves spotless but it helps a ton. The other issue is the ports on the head that feed into the valve cover get blocked and you get a compromised PCV system. I will post a valve cover DIY so you can see what I am talking about. If anyone wants pics or a link to this valve let me know....I wasn't sure if it was against the rules to post links to another forum?

    Here is the way the head breathes into the valve cover:

    [IMG]
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    robc1976

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    spot on advice here!
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    robc1976

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    Here is the RB vlave Vs stock

    Attached Files:

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