Alright guys, i failed smog today.

1986 2wd, 5spd, 22r, etc...

A week ago it started loading up on me real bad in the mornings and now whenever i let off the gas a bit and get back on it while driving, it wants to jerk/hesitate a bit. It feels like its running rich off idle and im sure the smog results will help you guys see the big picture.

Just want some input before i start tearing open the carb.

btw, truck is all tuned up: plugs, wires, cap, rotor, fuel filter, pvc, egr, oil are all good. Just wondering if im headed down the right path with the carb being the culprit.



Any help is greatly appreciated, thanks

 

failed on what? NOX? CO2?

try leaning out the carb first. dont let the idle get too far off or youll fail that too.

 

NOx are in line so it appears the EGR system and converter are working properly (working very well for that matter ).

It would appear the carb is the likely culprit, possibly a higher than normal float level, but I wouldn't rule out your timing and the operation of the vacuum advance / retard unit. Given you are failing HC at speed, the O2 sensor may be partially to blame but may not be the cause- it may actually be lowering your readings as much as it can.

What is curious is the O2% reading. Do you have the air pump or do you have the PAIR system for air injection (or neither...)?