Question about emission test
Question about emission test
(OP)
Hi
I have a 92 honda accord that failed the emission test. The car is very well taken care off (I mean oil change every 3000 miles, all the scheduled maintenance). Never taken it to anyone else but the dealer.
What is surpriseing is that only the NOX failes (1400 instead of 910) but the CO and CO2 were well below the limits (0.02 CO when the limit is 0.71) Same with CO2.
Is it possible to pass the HC test so well but still fail the NOx requirements?
Also any clues what would cause this?
Thanks
I have a 92 honda accord that failed the emission test. The car is very well taken care off (I mean oil change every 3000 miles, all the scheduled maintenance). Never taken it to anyone else but the dealer.
What is surpriseing is that only the NOX failes (1400 instead of 910) but the CO and CO2 were well below the limits (0.02 CO when the limit is 0.71) Same with CO2.
Is it possible to pass the HC test so well but still fail the NOx requirements?
Also any clues what would cause this?
Thanks





RE: Question about emission test
Shaun TiedeULTRADYNE Arl,TX(stiede@ev1.net)
RE: Question about emission test
Regards
pat
RE: Question about emission test
RE: Question about emission test
Mine passed easily today. If what I did didn't work my next idea was to put a resistor on the intake temp sensor to fool the computer to make a richer mixture.
Check out threads on water injection. Some guy made one for $20.
RE: Question about emission test
RE: Question about emission test
http://www.autoshop101.com/forms/h56.pdf
Cheers
Greg Locock
RE: Question about emission test
Wonder if you make any changes to your engine. The cause can range from many aspects:-
1) Freer flowing air filter
2) Different exhaust manifold or exhaust system
3) Different ignition timing by changing the EC setting
4) Different air to fuel ratio by changing the ECU setting
5) 'Expired' catalytic converter or the cat converter missing the important ingredient.
6) Etc.
Anyway, for engine tuner, it is always difficult to balance between the (HC+CO) and NOx. If you get the AF ratio too lean or the combustion pressure too hot, the NOx will increase but the HC and CO may decreased. You can also do it the other way around and get the NOx okay but the HC and CO to be bad.
The best is to strike closer and closer to the stochiometric mixture in order to get the optimum conversion rate from the cat converter.
AO
RE: Question about emission test
Good luck