Just got my e test done today, and it failed. At 40km/h, HC Was 53 ppm, limit is 52 ppm. CO % was at 0.75 and limit is 0.29. NOx was at 52 and limit was 578. Everything passed at idle.

I was missing the wire off my coolant temp sensor on the passenger side cyl. head. I believe that the engine wasn't reading that it was warm enough yet so it was pumping more fuel, making it rich. The low NOx suggests that the CC's were not up to temperature and that would cause the CO % to be high as well correct? I fixed the temp. sensor on the passenger's cyl. head, should that solve my problems? I was also told running methyl hydrate in the fuel would make my engine run a lot hotter, which might be enough to make it pass. Suggestions?

 

The temp unit in the passenger head is a switch for the radiator fan, not the coolant temp sensor for the ECM.

It's running rich. Need to find out why. Weak O2 sensor is a common culprit.

 

wouldnt a rich condition shoot the HC ppm through the roof?

 

High HC is from unburnt fuel (raw). More typically a miss than too rich, but really, really rich will do it.

CO will go up with too rich. Too rich makes NOx go down. This fits too rich.

 

okay makes sense

 

Anyway to test an O2 sensor?