Bimmerfest - BMW Forums - View Single Post - 335i Engine Hesitation between 2500 and 3000 rpm
View Single Post
Old 01-04-2012, 06:32 PM
Officially Welcomed to the 'Fest
Location: San Francisco
Join Date: Aug 2009
Posts: 10,410
Mein Auto: 2009 E93 N54
Originally Posted by Alpine300ZHP View Post

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.
Water injection will clean cylinder carbon big time...all will be gone. Usually done with 50/50 methanol, of course. Put a smile on yer mug too.

There is doubt same will clean intake valves where PCV carryover gunks & clunks 'em. $600 dealer walnut shell blast there unless you DIY for dramatically less - a little solvent and a lot o'DIY PITA labor.

But...should be no carbon buildup in a stock motor!

Last edited by CALWATERBOY; 01-04-2012 at 06:35 PM.
Reply With Quote