car won't pass smog, my first try at this

[karmasabish]

So, my 92 325i isn't passing smog. replacing the o2 sensor and the coolant temp sensor off the bat. Will check the plugs as well. Hopefully it's not a bad cat.... it passes everything except HC and NO at 15 mph

curious,

1. is there a smarter way to diagnose this stuff without just replacing everything and praying for the best?


2. had a turner chip on the car when it failed the first time, i replaced it with stock chip and took it back to the smog place and it was basically the same. Do i need to run the stock chip longer to get the DME to calibrate back to factory settings before smogging??


anyone else have experience with this? any guidance is very much appreciated.

[la36bmw]

the turner chip shouldn't affect your smog #s. my old 325ic passed perfectly fine with it in.

I was failing HC and NO at 15 too and it turned out to be the cat (yes I ran it hot as hell the second time and it still failed by twice the amount). I had changed the oil, plugs, cleaned the MAF, new fuel filter, o2 sensor. I ended up getting the magnaflow (cali legal one, dunno if there is really a true difference between the 49 state and cali legal but why risk it..) and it passed with numbers close to 0.

unfortunately the only way to really diagnose #s is to test it :[

[325x]

heres what i did to get mine to pass smog. I drive the piss out of it for about 10 mins before taking it in for smog, gets the cat nice and hot =D

[318isam]

fix your vacuum leaks................then seafoam................then run a bottle of "gauranteed to pass" before your next test..........;)

[gc325is]

CRC GTP may get you to pass the test but I think Cataclean helped me get my CAT working again. I would like to know if it helps anyone else. It's another $19 as I recall

[BlackBMWs]

So, my 318ti passed smog today after being classified as a Gross Polluter. The top test was Sunday, the second test was Monday after replacing the Catalytic Converter. It originally failed on the 15mph test for HC and NO as well. It barely passed the 25mph test.

http://i402.photobucket.com/albums/pp105/BlackBMWs/BMW%20318ti/DSC02479.jpg

A Magnaflow 36004 replaced the factory cat. I was happy that the second test turned out to be much cleaner than certinally the first and didn't cost me an arm and a leg. :cool

[la36bmw]

magnaflow cats ftw.