What's the deal? "CA smog failed twice" HELP!

[ros74911]

Hello, Pelicanites. Calling all smog experts. I have a 1983 guards red cab SC. I'm trying to get my car pass smog here in sunny california. It passed last smog 2007 88k miles and also tuned up. Now at 90k miles and it failed twice already. The 15 mph HC (PPM) measure was too high at 254. The last was 52. What can I do to fix this? I have checked oxygen sensor and for vaccuum leaks. I appreciate the input. Thanks in advance.

[Steve W]

high HC is either too rich, or unburt fuel - that's the black soot component of your exhaust.

[ros74911]

thanks, steve. do you think if i adjust idle screw it would help with fuel mixture?

[Steve W]

it might, but it also might not. theoretically your O2 sensor is modulating your mixture at stoichiometric, so your mixture shouldn't be either too rich or too lean. But you should check and adjust idle CO properly anyways. I'm rusty on the proper terminology for CIS, but the idle screw should be adjusted so the lambda valve is operating at a 50% duty cycle using a dwell meter.

Other possible causes, spark misfire could also be causing unburnt fuel in your exhaust. Also dirty or stuck injectors could be injecting excess fuel in a particular cylinder(s).

[avendlerdp]

How did you check your O2 sensor? It' sounds like yours has gone bad.

[ros74911]

thanks, avendlerdp and steve again.

i didn't check the O2 sensor. but i'll do that. how do i know when my 02 sensor is bad?

RE: dwell meter. i don't have dwell meter. i would have to take to a shop to do it for me.

[ruf-porsche]

If you haven't replace the 02 sensor after 90,000 miles, it's time to do so.

[ros74911]

ok, thanks guys for the input. hopefully the sensor will do it. thanks.

[ClickClickBoom]

Originally Posted by ros74911

thanks, avendlerdp and steve again.

how do i know when my 02 sensor is bad?

You don't pass smog......twice!
eric

[ros74911]

hi, guys. found out that my sensor has broken ceramic connector from top. i don't what it's called. not sure if our host got them. i tried to do a parts diagram. it's not letting me. do you guys know what part that is or part number. thanks.