my '85 S10 blazer 4X4 2.8l v-6 carb model failed NJ emissions for High Idle for CO% at 3.96 where it should be below 1.20. The HC was at 139ppm compared to max allowable 220ppm. It passed regular idle with CO at 0.47% vs 1.20 max allowable.

I just got this truck and it seems sluggish (compared to my '93 4.3 Vortec) but runs pretty smooth. I changed the air filter and got an oil change and looked like the PCV valve was OK.. I sprayed the carb in & out with carb cleaner and also looked for vacuume leaks (found none). going to try another pass at inspection but guessing it will fail since it is so far out.

any ideas??

 

Gary,
Does that year:model have a charcoal canister? High CO means too much fuel (see link below).


If someone has tried to add gas to the tank from a gas can, especially the ones with those crinkly plastic spouts, liquid fuel can pour right into the canister and saturate the charcoal.


Just a thought.


-Roman


(AirCare emissions testing program | Repair Info - Causes of Excess CO Emissions)

 

Thanks! I read that about the vapor canister being saturated being a potential cause and will have to look at that. But I don't remember adding gas with a can to that truck in like forever so I'm doubting that.


The thing that gets me is that is passes at idle but fails at the high idle (when they race the engine). I'm going to bring it back & let them check again after looking for the vapor canister..