Re: high hydrocarbon in exhaust

["jtrealtywebspannet" <jtrealty@xxxx>]

If you read and follow the procedures in the Workshop Manual 
D:04:01-04 you will discover that you are measuring the HC ahead of 
the catalytic converter. It is VERY IMPORTANT that you follow the 
procedures exactly if you want to do it right. If after following 
these procedures and the HC is still too high then the catalytic 
converter MAY be bad. 
ONLY DO THE ADJUSTMENT AFTER VERIFING THAT THE FUEL AND IGNITION 
SYSTEMS ARE OPERATING PROPERLY. You cannot adjust ANYTHING to correct 
for an improperly running system! Variation in the HC can be caused by 
the Lambda system hunting, the idle system hunting, an intermittant 
breakdown in the Secondary ignition circuit, and a dirty fuel 
injector. Other possible causes could be valve adjustment, low 
compression on 1 or more cylinders, misfiring plugs, etc.
The purpose of the "smog check" is to see if the car is in tune. Just 
fiddling with the adjustments won't get you there, something is wrong 
and you will not adjust it out. In the procedure one of the first 
things it says THERE MUST BE NO AIR LEAKS PRESENT, THE IGNITION SYSTEM 
IS OK AND CORRECTLY SET!!!!!!! If you know you have a vacuum leak you 
should not be touching the mixture screw as in all probability if you 
fix the leaks and tune up the ignition system you won't need to adjust 
the mixture. With the Lambda "dead" how can you adjust the mixture? 
Replace the dist cap, rotor, ignition wires and plugs, fix ALL of the 
vacuum leaks and try again. After getting the car running right the 
converter will be OK unless contaminated by lead or other contaminates 
from gasket sealer. MAKE SURE THERE IS A PLUG INSTALLED OVER THE 
MIXTURE ADJUSTING SCREW. If missing this causes a vacuum leak and 
throughs off the mixture.
David Teitelbaum
vin 10757


--- In dmcnews@xxxx, "rendy_cheng" <rcheng@xxxx> wrote:
> Hi Everyone!
> After adjusting air/fuel mixtures screw, the HC is a bit better, but 
> not good enough to pass the smog check.