Failed HC Smog Emission Test?

Question

Okay I failed a HC test at idle.  I was kinda shocked actually.  Its a run around car for the nieces etc but it runs really well.

Here are my findings.

Idle HC 220/359 (standard/reading)  FAIL
Idle OC 1.2%/0.48%  (standard/reading)  PASS

High HC 220/100  (standard/reading) PASS
Idle OC 1.2%/0.6%  (standard/reading) PASS

Clearly im running too rich or have compression problems.  

But their computer broke and my car set for over 1 hour in freezing weather.  It wasnt hot when they tested it and I asked to test it again they said it wont make a difference.  To me that is BS.  So I want to go in and let it run for awhile and leaving it idling while it waits in line.

I will change the plugs and maybe make the fuel more lean with some ethanol.  

Any other ideas?  Other then waiting to not do this in freezing cold weather?  Oh BTW its a 95 Olds Cutless Supreme 

Thanks

Tyler C · Accepted Answer

if i where you i would go get my car smogged again but this time drive it on the freeway for about 15 minutes then take it to the smog shop and keep it running.  this way you can get your catalytic converters real warm and this can usually get the hydrocarbons down (HCs).  also try checking your air filter because if that is clogged it will starve the motor for air and will cause the motor to go rich.

valencia · Answer

High HydroCarbons are being emitted at too many parts per million.. most likely it will not be a wiring problem... it may however be attributed to bad spark plugs and incomplete combustion.... it will have to be checked at your dealership and should not cost more than an hour or two in labor.... good luck...

Anonymous · Answer

well like you said try to make it run leaner maybe getting a better spark will help and make sure there isnt too much oil leaking into the combustion chamber.

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Failed HC Smog Emission Test?

3 Answers