well the first time i took the car i failed for all emissions... replaced the cat and now i only failed for Carbon Monoxide. It's supposed to be .99 or lower and i was at 2.99

What could this be? Oxygen sensor maybe? Check engine light is not on

 

anyone?>

 

How bout a setup list....?

 

93 civic dx 1.5L 5spd

 

????

 

.

 

I WOULD CHECK OUT THE CAT. The cat changes the CO to Co2 which is supposed to come out the exhaust.

Cat changes...

HC to h2o
CO to co2
NOx to N2 + O2

So if you have carbon monoxide it means the metal in the cat i think the platinum (which does the CO) is worn down and not functional.

 

cancel that i misread what u said in the first post. I would run an engine cleaner through the motor. Because it would throwa code if the 02 sensor was shot.

 

check your whole exhaust system to your headers . . see if your o2 sensor is connected (on headers) or if its broken alot of ppl usually mis-place it when taking it out, theres as plug that connects to it . . also if your exhaust/pipings have holes on them they wont be able to get a clear reading when doing a IM testing . .