Black smoke when WOT

orionredwing · 08-11-2011, 09:47 AM

Hi guys, my 77K mile car is starting to throw out a cloud of grayish/black smoke everytime I go WOT (only go WOT when car is warm).

What are the causes of this grayish/black smoke and is anyone else having this problem now that the car is getting older?

After replacing spark plugs last time, I noticed my injector #3 was marginal, as my brand new plug was black w/ fuel smell on it (swapped coils so not a coil issue).

My real question is, besides this marginal injector #3, are there any engine seals that need to be replaced? I remember as part of a 100K maintenance on my older cars (like Honda Prelude), I also got the same black smoke on WOT, and the mechanic said some seals / gaskets in the engines had to be replaced. It was just a standard maintenance thing you had to do when you're approaching 100K miles.

Was wondering if we have to do that for our cars, and if anyone had done it?

Thanks!

BMWsky · 08-11-2011, 10:08 AM

I could be wrong, but I always thought black smoke or soot on the exhaust pipe was a sign of a rich AFR. Gray smoke is usually the opposite.

Jeff@TopGearSolutions · 08-11-2011, 10:17 AM

Could be rich, could be dirty valves or it could be turbo seals going.

Rotary Rasp · 08-11-2011, 10:22 AM

My first guess would be the turbos are failing, but I really know nothing on the matter.

08-11-2011, 09:47 AM	#1
orionredwing Captain 106 Rep 728 Posts Drives: 335i Sedan, 135i Coupe Join Date: Dec 2006 Location: San Jose iTrader: (0) Garage List 2007 335i [10.00]	Black smoke when WOT Hi guys, my 77K mile car is starting to throw out a cloud of grayish/black smoke everytime I go WOT (only go WOT when car is warm). What are the causes of this grayish/black smoke and is anyone else having this problem now that the car is getting older? After replacing spark plugs last time, I noticed my injector #3 was marginal, as my brand new plug was black w/ fuel smell on it (swapped coils so not a coil issue). My real question is, besides this marginal injector #3, are there any engine seals that need to be replaced? I remember as part of a 100K maintenance on my older cars (like Honda Prelude), I also got the same black smoke on WOT, and the mechanic said some seals / gaskets in the engines had to be replaced. It was just a standard maintenance thing you had to do when you're approaching 100K miles. Was wondering if we have to do that for our cars, and if anyone had done it? Thanks! __________________ PROcede \| AMS FMIC \| AR Catless DPs \| AR Oil Cooler \| BMS DCI Wavetrac LSD \| KW V3 w/ Swift Springs \| M3 Front Suspension Last edited by orionredwing; 08-11-2011 at 10:48 AM..
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08-11-2011, 10:08 AM	#2
BMWsky Major 24 Rep 1,244 Posts Drives: 335i Join Date: Dec 2010 Location: Webster NY iTrader: (1)	I could be wrong, but I always thought black smoke or soot on the exhaust pipe was a sign of a rich AFR. Gray smoke is usually the opposite.
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08-11-2011, 10:22 AM	#4
Rotary Rasp Lieutenant Colonel 241 Rep 1,857 Posts Drives: 2009 E92 335i 6MT Join Date: Aug 2008 Location: SoCal - Torrance iTrader: (6)	My first guess would be the turbos are failing, but I really know nothing on the matter. __________________
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08-11-2011, 10:17 AM	#3
Jeff@TopGearSolutions 3441 Rep 79,212 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	Could be rich, could be dirty valves or it could be turbo seals going.
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