Bimmerfest - BMW Forums - View Single Post - CEL emissions issue with Akropovic Exhaust
View Single Post
Old 10-07-2012, 03:17 PM
gotrice415 gotrice415 is offline
Registered User
Location: San Francisco Bay Area
Join Date: Apr 2012
Posts: 76
Mein Auto: M3, 335Ci, X5d, 750i
Originally Posted by Orient330iNYC View Post

the exhaust valve flapper malfunction does not set a cel. if you unplug the flapper at the solenoid you throw a silent code in the dme indicating an open circuit. if you leave it unplugged there is no code as the component is not an emissions component. if you read the post by ct, the exhaust the op installed is catless, which will throw an emissions error code as there are no cats. the flap has nothing to do with emissions.

leaving the vac hose unplugged will NOT set an emissions fault or cause any kind of lean/rich condition...

Sent from my Galaxy Nexus using Bimmer App
Wow, where does engine vacuum come from? I only do this day in day out for a living at a dealership. Yes you are right that the flap is meant for noise reduction. But how about you take a look at documentation on when and why the flap would open. So your tellin me that if you induce a vacuum leak it wont throw a code or cause a lean mixture issue? How about you test that theory and leave your oil filler cap off or disconnect a vacuum line under the hood. Vacuum is created by the engine with low pressure differential. With N54's there is a vacuum pump since adequate vacuum cant be established at higher rpms. Do a few drive cycles and let me know what you find.
Reply With Quote