Problems passing california smog check 98 Civic Ex
#1
Problems passing california smog check 98 Civic Ex
I have an 98 Civic Ex (1.6L Vtech, SOHC, 16Y8). It has 200'000 miles, but the engine is in great shape (no oil burning, no leaks, etc).
2 years ago it failed the smog check pretty bad. I ended up replacing both O2 sensors and the Cat. That was about 30'000 miles ago. Now it failed again. My numbers are as follows: %CO2: 14.5, %O2: 0, HC: very high (about double the allowable max), CO: high (about a third more than allowable), NO: very low (about a third less than average).
Anybody has an idea what could be wrong? Tune ups done regularly.
Thanks for the help in advance.
2 years ago it failed the smog check pretty bad. I ended up replacing both O2 sensors and the Cat. That was about 30'000 miles ago. Now it failed again. My numbers are as follows: %CO2: 14.5, %O2: 0, HC: very high (about double the allowable max), CO: high (about a third more than allowable), NO: very low (about a third less than average).
Anybody has an idea what could be wrong? Tune ups done regularly.
Thanks for the help in advance.
#2
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Re: Problems passing california smog check 98 Civic Ex
Just my .02 but in order to find out exactly what is causing your high Hydro carbons, you need to perform a complete diagnostic. From what I have heard, a high HC reading can be caused by running to rich or not adequatly burning the right amount of fuel.
If you want you can replace Plugs/cap/rotor/O2/wires/cat in that order.
Bump for someone who has more excperience.
If you want you can replace Plugs/cap/rotor/O2/wires/cat in that order.
Bump for someone who has more excperience.
#4
Re: Problems passing california smog check 98 Civic Ex
Thanks for the suggestions.
No error code of any type, no problems. Timing is on the dot and thermostat works perfectly.
What I'm gonna do for now is I'll send in the fuel injectors for sonic cleaning and I'll put on a new fuel pressure regulator.
Any other ideas welcome
No error code of any type, no problems. Timing is on the dot and thermostat works perfectly.
What I'm gonna do for now is I'll send in the fuel injectors for sonic cleaning and I'll put on a new fuel pressure regulator.
Any other ideas welcome
#5
Honda-Tech Member
Re: Problems passing california smog check 98 Civic Ex
I would say do a full tune up also. And make sure you have changed your PCV valve. Besides that i wish u good luck.
#6
Re: Problems passing california smog check 98 Civic Ex
Measure the fuel pressure before replacing the FPR.
Check whether any fuel injectors are stuck open before cleaning them.
Check for an exhaust leak near or upstream of the primary O2 sensor.
Test the primary O2 sensor.
Adjust the valve clearance to spec.
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#9
Re: Problems passing california smog check 98 Civic Ex
I had it done with the injectors on my 88 CRX Si just because it had 300'000 miles. 2 were fairly clogged up. Car runs much better now.
About the leak in the exhaust manifold. I'll check but I doubt it since I have a fairly new header on it.
Thanks to all for the help
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