garyhgaryh

Is there anyway I can richen up my VX for smog testing?
I'm passing at a low 9PPM HC, but failing NOx. If I can richen up the mixture, I can lower NOX. On BWM's you can turn a **** on the AFM to richen the mixture. Anything similiar on the VX?

thanks,
Gary

thesmogman

You might need an O2 sensor. Has alot to do with A/F ratio's

Unfortunately the computer will try to compensate for what ever you do.

I have had more than a few in the shop that the O2 sensor was stuck and they were running lean with Nox failures. Including my own car.

garyhgaryh

really? Can I get a generic O2 sensor that will fit the vx? I know these cars have wide band sensors.
Gary

garyhgaryh

I thought failsafe mode the O2 will make the car run richer?
Gary

thesmogman

Yes It would but then you would fail the check engine light test.

garyhgaryh

Oh man I pass smog today!

Prev tests:

MPH HC CO NO
15 9 .02 1826
25 8 .02 1635

Today's test

MPH HC CO NO
15 38 .09 185
25 19 .05 178

I cut my NO by 10 folds!!!

So, how did I do it?
Of order of importance, I think:

1. timing from 16 to 13 deg
2. clean EGR passageway by replacing intake with a known good one (I would put that as #1 but my intake was not completely clogged when I tested it)
3. cleaned carbon from intake ports on the engine and new intake (esp near the injectors)
4. new plugs - one step colder gapped at .041-.043; original one was probably 5 years old and had a gap of .60-.70 when taken out
5. New air filter (probably did nothing - I should have kept the old one in since old dirty filter will increase HC (which is what I want).
6. Cleaned EAVC (screen plugged) - not sure if this can affect NO

I went in early before temps hit 100 deg. Last time I warmed up the car for 30 minutes driving it on the highway. Not this time. I drove it to the test only station 5 mins away turned it off and waited. Engine cold when the guy arrived. This should be #3.5.


My goal was to richen up the mixture somehow. I think retarding the timing helped, but not sure how it affects gas mileage. Since it's a commuter, I will probably advance it back to stock or higher.

Anyways, this smog saga has come to a close for me. I spend so much time on it that I was getting frustrated and was wondering if it was worth it. Since I commute about 120 miles/day, I can say it was worth it.

Gary


Modified by garyhgaryh at 9:58 AM 9/3/2007


Modified by garyhgaryh at 9:59 AM 9/3/2007


Modified by garyhgaryh at 5:46 PM 9/3/2007