Cpt.Zanzibar

well i went to go get emissions done for the 2nd time and i passed all but my hydro carbons. i know this is in the faq but HC is unburned fuel correct?? plus im pretty sure mky car is running very rich because it smells pretty gassy(fuel). how do i change the ratio so im not runnin so rich??

J-Rat

iTrader: (2)

Was it an idle or a loaded reading?

Cpt.Zanzibar

well on the graph it shoots up when accelerating.

byronl

how's ur o2 sensor?

Cpt.Zanzibar

i dont know.

Cpt.Zanzibar

bump, i have to get this done

byronl

buy a new o2 sensor, when i had my car smogged i had a bad o2 so i bought a new one and the hc's were down.

J-Rat

iTrader: (2)

02 wont help acceleration, only cruise and idle. Why are they measuring transient load anyways?

ericgrau

iTrader: (1)

I believe they measure smog at cruise and idle.

O2 sensor sounds like the answer.

Yes, HC is unburnt hydrocarbons, i.e. fuel. CO is carbon monoxide, which forms instead of CO2 when fuel is burnt in insufficient air (mixture too rich). NOx is nitrous oxide, which forms at high temperatures and pressures when there is too much air (mixture too lean). Inside your cat O2 (from the air pump) and NOx react with HC and CO to burn the HC, make CO2, and make N2 (nitrogen gas). I'll bet your CO was high and your NOx was low on your smog test.

J-Rat

iTrader: (2)

Not debating that point, but there ARE things you can do depending on what condition the measurement is failing.