280z still didn’t pass. But got some useful data.

From the previous post, I installed a new catalytic converter, popped in new spark plugs, and re-filled an empty tank with 87 octane. Here are the old / new numbers:

CO% Levels   1st Try   2nd Try  
15 MPH 1.36 0.17 2.03 1.73
25 MPH 1.16 0.15 2.66  n/a

1st Try: Catalytic converter was supposedly original, but no numbers when inspected. Bosch Platinum Plus spark plugs had heavy carbon buildup. Ran 91 octane gas.

2nd Try: New Magnaflow catalytic converter, NGK spark plugs and 87 octane gas.

Thankfully Nguyen from Smog Tech did a quick CO% test just to see where we’re at. It ran steadily at 1.73% CO, just 0.37% more than MAX. Okay, time to adjust the 280z’s AFM (Air Flow Meter) to run a bit more lean air/fuel mixture.

3rd times a charm, right?… right?