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Old 01-04-2012, 01:24 PM
Alpine300ZHP Alpine300ZHP is offline
East Coast Commuter
Location: South Florida
Join Date: Jan 2007
Posts: 4,045
Mein Auto: M4/X6
Originally Posted by Blubaron79 View Post
Awesome! Thanks for the suggestion. Can I use any other type of fuel cleaner??? Or BMW fuel cleaner only?

I think I haven't used fuel cleaner enough in this car.
Mike Miller tells me to stick with BMW fuel system cleaner plus so I trust what he says. There is apparently some difference from the BMW stuff and the Techron stuff you buy at the auto parts store. Given the nominal price difference (less than 3 bucks a bottle) I will buy the BMW stuff.

Originally Posted by jburke4689 View Post
Alpine, my car idles smooth as silk and runs great at all rpm. The only problem is the one I described on my post. The car even runs smooth at 2500-3000 rpm when cruising. It is only under load that I get the roughness.
Under load roughness and a smooth idle is, more than likely, injector buildup. I would still recommend you run 4 tankfuls of BMW fuel system cleaner plus even if you do not to the high RPM drive. I would still do the high RPM drive as it can only help and cannot hurt.

Originally Posted by jburke4689 View Post
I visited my dealer today and talked with the service manager. The car has been there 2 weeks. He told me that the regional engineer from BMW NA was there and they aren't sure what it is yet but are leaning toward the wastegate. I never had the rattling issue but wastegate sounds right to me based on the symptoms. Feels like the boost is dumping in that rpm range. I hope they do a goodwill repair. Even with the class action (wastegate warranty extended 1 year or 12,000 miles) I am screwed. I have 67k on mine. Hopefully they will take into account the fact that they replaced my low pressure fuel pump for $700 and that didn't fix it.
Maybe it is the wastegate, but before you pay them money to replace/fix the turbos why don't you try my suggestion. If my suggestion fails to improve the problem then consider wastegates. It is rare for wastegates to malfunction without codes and noise...

Originally Posted by Blubaron79 View Post
I stopped in last night to grab some fuel system cleaner. The SA said it was carbon build up if I only felt it under light engine load on the highway. She said to run 1 to 2 bottles of cleaner through it, and all should be good. The Westgate would be throwing a SES light, plus 2009 is when BMW started putting the upgraded Westgates on to get rid of any Westgate problems.
I agree with everything you said about the wastegates and it sounds like your S.A. basically told you to do what I did. Let me make sure you understand (as you S.A. seems not to understand) that on a direct injection motor as the N54 the fuel system cleaner plus will not clean the carbon buildup. If the fuel cleaner helps it is only because there was injector buildup (which is quite common on the pizeo injectors). The high RPM run is the only thing that will clean up carbon buildup on the valves (or an engine cleaning with walnut shell blaster for $500 bucks) because that is the only way to get the motor hot enough to start breaking the carbon down and blowing it out.....heat is what gets rid of the carbon....sustained high heat. Since we are not sure if the problem is one or both of these I recommend my dual approach which addresses both issues at the same time and is more effective than telling people to do each remedy separately.
~ 15 M4 (Mine)
~ 16 X6 (Hers)
- Previous BMW's - Way too many to list here (21)

Last edited by Alpine300ZHP; 01-04-2012 at 01:31 PM.
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