"hex" wrote:            98 civic EX manual 109K

Failed california smog test - high HC.

Did new plugs, dist cap and rotor, added 2 cans
of heet to 1/4 tank of gas and  ran for 15 miles
on fwy prior to retest.  HC was about 30 points
lower but still failed:

            15 mph           25 mph
         Actual(Max)     Actual(Max)
CO2        13.7              13.8
O2           0.7               0.5
HC         99(64)           89(47)
CO       .16(.55)          .10(.54)
NO        33(477)         13(764)

No codes.  Engine strong.  Don't want to start
throwing parts dollars at it without knowing the
cause.  Any insight appreciated.
________________________________________

Looks like it's still running too rich.     If you do
decide to throw parts dollars at it, start with a
new air filter and plug wires.

Good luck.

Rodan.

The high HC means incomplete combustion. High CO means too much fuel,
and high NOX emissions almost always indicate a problem with the EGR
system. In this case your mixture looks okay as it is well within the
test limits.

Adding heet (and 2 cans at that) to 1/4 tank of gas is the wrong
approach to this problem. Heet is wood alcohol, and while what you did
would likely help a carbureted engine pass an emission test by leaning
the mixture, it will not have the same effect on a fuel injected
engine. The computer will automatically adjust the fuel delivery to
maintain a stochiometric mixture by introducing MORE fuel(since your
alcohol mixture has less energy than gasoline), and thus the only
effect you've made is to cut your gas mileage and take any water in the
tank (which will be absorbed by the heet) and stick it into the
combustion chamber(wood alcohol will bind to the water and drag it
through the system), where it will not burn.

My advice: Fill up the tank with fresh gasoline to dilute the heet that
you put in there and run it through again. I would also like to see the
other numbers from your first pass through the test. Keep in mind at
109k you are probably due for oxygen sensors and a mass airflow sensor
in the very near future.

And here's the clincher...if you drove the car with a misfire for any
period of time it is also possible you destroyed the catalytic
convertor, and if that is indeed your problem no amount of pouring
stuff into the tank will get you through the test. Any shop can test
the cat with a point -n- shoot thermometer. If after running for
several minutes at a high idle RPM the inlet side of the cat is the
same temperature as the outlet side then you can safely assume it is in
need of replacement.

Good luck with it.

Chris