Failed HC emissions!

Bourdin, Vincent BOurdin@ptc.com
Tue, 1 Apr 2003 08:56:05 -0600


Hi all,
Last week-end my 92 NX2k with 110k miles failed HC emissions! Here are the
results:
  Reading Limit
HC 02.12 01.20 Fail
CO 10.55 20.00 Pass
NOX 00.81 02.50 Pass
Looking in the achieves, I mostly found info about NOx related problems, but
not much specifically about HC.
Looks like I'm doing ok with NOx although I have no idea (yet) how my EGR
system is doing. I did find couple of cracked hoses between EGR components,
which I fixed, but that should not affect/improve HC level, right?
Regarding HC specifically (unburned fuel?), looks like I should check all
these sensors: O2 sensor, MAP/MAF, TPS, RPM, and CTS. Since I've only had the
car for 2 years, I don't know what shape they're in, and will test them before
changing them if needed. My guess is they are stock!
As part of my spring clean-up, I also plan on doing TB, Fuel Filter, plugs,
oil/filter, PCV, etc ...

Is there anything else you guys suspect could be wrong?

Also, I'm now thinking that my car was probably not warned-up enough for the
test, could that have played a role in the failure? Keep forgetting how cold
it is in Boston!

Thanks,

Vince