So I failed the smog at the 25MPH test: high Nitrous Oxide levels w/ Low CO. My VIR report at smogtips.com mentioned there's a possible lean fuel condition, possible vacuum leak, or possible defective CAT. The smog tech suggested that I replace the CAT, which i did. I haven't gone in for a retest yet, as I'm still blowing out white smoke under the following scenario: driving on freeway and after letting go of the gas for like 4 seconds & then moderately hitting the gas pedal again. When that happens I see a big cloud of white smoke in my rear mirror.

FYI...before the smog test I removed my CAI & used my stock air box, but forgot to reset the ECU. Could that have caused my smog test failure? After I installed the new CAT, I did the ECU reset but as I mentioned above the white smoke issue is now more obvious.

THoughts?

 

could be burning some oil, although oil buring ussually contains a slight blue tint. i just smogged today, nox was over 200 points above max, retarded the timing to 16 degs, made a huge difference, went from around 800 down to 200-300ish. ur timing maybe to advanced leading to a lean condition and high cylinder temps. also tech mentioned to me that if there is alot of carbon buildup in the cylinders it can start to soak up the fuel leading to the same lean condition. i would try retarding the timing, maybe even retarding it as far as u can go, hopefully the tech is cool and doesnt sit there and verify what the timing is at with a light

 

Brake fluid burning makes white smoke. If your brake booster has failed or is leaking, the vac line to it will suck the leaked fluid and burn it. This may not be the problem but it may be something to look at.

Vac leaks, like you said, will also cause lean, high carbon readings. Check for vac leaks by spraying starter fluid or something really flamable around vac lines and gaskets, one area at a time. If the motor revs, you found your leak. Just be sure to use a really hot chemical. WD40 or brake/carb cleaner won't always do it. If that is your problem and you need a really quick and ugly fix, spray paint around the leak. The paint will get sucked into a tiny crack or leak source and then dry and seal it. its ugly but it works in a pinch.