Finished installing catalytic converters in my new to me 2005 M3 yesterday. The car was on jack stands at my dad's for a solid month while I ripped apart the exhaust, moved the post-cat O2 sensors to the bottom-middle of the car after the new cats (from the headers .. this was a pain), removed this weird clutch delay valve that BMW put in their cars during that time period, and replaced / bled brake and clutch fluid. Miraculously, the car fired right up the first time after putting it all back together and seems to be fine. I think I'm going to take it to a shop and pay for an hour of their time to check for exhaust leaks and make sure the brakes/clutch are bled properly, just for peace of mind. I'm tired of being under that car and want to make sure it's all good since this was my first exhaust work :biggrin:
Almost ready to pass MA state inspection ... (stupid non-emissions-compliant Florida cars )
edit: replaced cabin and engine air filters too since the intake and cabin filter slot were all apart anyway. The old ones looked basically new but now I know when it was done ...
Those delay valves were so goofy. Pulled one from an e39 540i once, made a solid and positive difference.