CA Smog Test Fail High NO

Post here for mechanical and engine topics such as fuel issues, transmission problems, rough idle, exhaust, electrical issues, etc

Moderators: GRNSHRK, ron, bfons

Post Reply
Russm21
Posts: 33
Joined: Tue Jul 14, 2020 8:45 pm
Location: SoCal

CA Smog Test Fail High NO

Post by Russm21 »

Greetings all.

I recently purchased this vehicle and have been having some issues with passing a smog test. My smog test guy has been helping me out by giving me a pre-check to get things sorted out prior to the official check. The big issue, at first, was high HC. The first checking I did had the HC come in at 1300 at idle. I changed the O2 sensor, air filter, gave it an oil change and replaced the fuel pump (the one on the car was not correct). Doing all this brought the HC down to 300. A lot better but still too high. The catalytic converter in the car was suspect so I had a new Magnaflow unit installed. HC problem solved! However, this is what happened...
20200812_124802.jpg
20200812_124802.jpg (902.53 KiB) Viewed 2054 times
Everything looked great but the 25mph NO went through the roof! How could the NO go from 1 at 15mph to 2704 at 25mph? I don't get it.

Has anyone dealt with this before? AFM perhaps?
Russell
1989 E30 325ic
1986 E24 635CSi
Post Reply