If it was running as rich as you seem to be worried about, you're NOx
wouldn't be that high. Both values high would make me believe it was a bad
cat and nothing more complicated than that. And a years time is more than
time enough to finish off a cat, it either has catalyst left or it doesn't,
there isn't really a "last leg" condition for a cat. I'm actually kind of
shocked it lasted for 200k miles. Does your exhaust stink? Like a rotten
egg smell? another bad cat symptom. You could always borrow a buddies cat
for a day just to see if that is indeed the culprit.
-Chad Sullivan
----- Original Message -----
From: "Ryan" <[EMAIL PROTECTED]>
To: "CRX (E-mail)" <[EMAIL PROTECTED]>
Sent: Monday, July 01, 2002 8:50 AM
Subject: CRX: ZC running rich - many questions
> I need help cleaning up the emissions on my ZC motor (standard ZC 1989
> vintage). I went to have my yearly state emission test with the new ZC
> motor and it failed on the Hydrocarbons.
> The readings for the 2500 RPM test were 67 ppm (220 allowable) and 363 ppm
> at idle (220 allowable). The NOx was pretty high also but they weren't
> required to test that part.
> When I put the engine in a few months ago I did all the normal replacement
> of tune up parts - Spark plugs, spark plug wires, distributor cap & rotor,
> and ran a bottle of SI1 fuel injection cleaner through it.
> The guy at the testing center was kind enough to test it in manual mode to
> see what kind of HC it was putting out at different RPMs. When he let off
> the gas the HC count went way up to 1000. He said it was probably the
> Catalytic converter and although I somewhat agree with him on that, it
> doesn't explain how the HC count was so low in the previous years tests.
> Last year it was 78 at idle and the year before it was 68. I think the
cat
> is the original with 200K miles on it, but if it was in about the same
shape
> the year before why did it run so clean?
> I have also checked the timing and both cams are aligned where they should
> be in relation to the crank. I was thinking of getting an AEM adjustable
> cam gear and taking it to the dyno and see if I can dial out some of the
HC.
> Is it possible there is too much overlap in the exhaust cam? I also have
3
> different computers I can try in the car, an SI, a 88 Integra, and the ZC
> one which is the one I have been running.
> I think by just sticking on the cat it will probably clean it up enough,
but
> should the motor really run that rich?
>
> Ryan
> Cumming, GA
>
