my vehicle just recently failed smog, had the cat converter & o2 sensor replace last year; throttle body been cleaned, performed fuel injection service. reason why it failed was due to high nox. here is the reading.
- car sat 5 minutes before initial test; just got off highway, drove hard.
5 speed transmission. car not equip egr.
co2 02 hc co no
15: 15.24 0.07 58 0.56 1223 max: 708</span>
max 89 0.53

25: 15.40 0.02 24 0.29 332 max: 746</span>
max 54 0.51


vehicle all stock.


any ideas? timing was at 16btc during test.
when i did a retest with at 8btc, it all pass fine, but still failed at timing.

 

High NOx readings result from high combustion temperatures or high combustion pressures. what octane gas are you putting in your car? Are there any additives like ethanol? What is your engine code out of curiosity?

 

stock motor, b18b1. running normal87 octane w/o any addtives, just my commute car. i tried running seafoam into the intake to clean off carbon buildups, not sure how well it worked out. any ideas?