Join Date: Oct 2002
Location: sf east bay ca.
Thanked 431 Times in 348 Posts
Re: FAQ on Carbon Build-Up Issue (First Attempt)
this is just speculation, but i think this is similar to the problem porsche had with earlier 993's (i think that was the model). It's the smog pump passages in the heads that get blocked with carbon, so when the smog pump runs on the cold start, it can't blow enough air into the exhaust. There really should be a way to access this from outside the engine, i'd think, by going thru the smog pump passages, perhaps with a chemical, compressed air, pipe cleaners, who knows... It sounds like a design issue really, hard use may not do anything, depending on where these ports are. It would be nice to have some type of schematic of the head to see where we are really dealing with.
signed, concerned at 67k!
93 M5 3.8 Sterling Silver, Black 5/93 production (euro)
94 M5 Touring Madeira Schwarz, Black 10/93 production
84 728i - M88 powered