Need help translating read out
My 91 305 TBI failed emission test. all stock but for the cat-back exhaust, car runs fine but will puff blue on start up (has done this for sometime but has always passed)

HC
driving 117. =fail (88. max)
idle 247 =fail (82 max)

NOx
driving 603. =pass (953 max) ....higher than average but still a pass

CO
driving .11 =pass (.64 max)
idle .08 =pass (.50 max)




any ideas on where to start?

 

Most likely unburned fuel. Check ign timing, spark plugs, thermostat.

 

CTS first; then a cat.

 

Any codes?

 

gonna pull the plugs tomorrow replace and its due for oil change too.
whats a CTS? good point about the cat probably due for a replacement anyway.
there are no codes

 

Coolant Temp Sensor

Those often fail such that they tell the computer that the engine is WAY cooler than it really is, which makes it feed too much fuel.

 

Good little guide:

http://www.salemboysauto.com/original-faqs/faq-20.htm