Failed Emissions

[CB-M3]

yeah I went to the parts store and got to scramble thru their wall of hoses. It costs more than the BMW dealer oem part. Might be because of the funky bends. I ordered that hose from the dealer for $8. I might still try to find a 90deg hose and do it direct like you said. it is 5/8" at the ICV and 1/2" at the other end.

[CB-M3]

So I did the direct connect with new hose i bought that had similar bends coming off the ICV. I used a new 5/8" hose and got a reducer connector to transition to the 1/2" hose to intake boot. Connections are tight. Clamps were not needed as the connectors are the ribbed type. I can add them later. Right off the bat I noticed my idle at cold startup is steady. No jumping around searching for RPMs. Did several more hot startups and it's steady. Next step is the O2 sensor.

[CB-M3]

Should I reset the ECU after I closed the vac leaks?

[CB-M3]

Ordered an O2 sensor. Going to replace that first before I take it back for retest.

[oldmann]

You can reset the codes if you want, makes no difference, unhook the battery for 10 15 min.

Get it out on the hwy after you change the O2, let everything get good and warmed up before taking it in to test, don't shut it off before the test.

[CB-M3]

thanks for the advice. will do. I still haven't returned the cat just in case I do need to replace it.

[CB-M3]

so I failed 2nd time. All the emission levels went down except NOx. After replacing the O2 sensor and fixing the vac leaks all the HC, CO, CO2 levels went really low. Gotta replace the 22yr old cat.

[decay]

Post results from 2nd test?

[CB-M3]

3rd time is a charm. I replaced the cat with a Magnaflow universal. Passed all gases. I drove it for 30-45 minutes and took it straight to inspection station.