Bimmerfest - BMW Forums - View Single Post - Noise at cold startup
View Single Post
Old 01-28-2005, 08:11 AM
al_r al_r is offline
Registered User
Location: Chicagoland
Join Date: Jan 2005
Posts: 2
Mein Auto: '96 328i
That is your secondary air pump, 'injects' fresh air into the exhaust manifold at start up time till the ECU shuts it off - strictly emissions related. If the pump fails, you'll get a CEL/code indicating 'not enough volume' in the front or rear engine banks.
If you decide to replace it, also replace the valve it feeds on the exhaust manifold.
Reply With Quote