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high NOx level 96 Camry

3877 Views 5 Replies 6 Participants Last post by  Andrew Liu
I just smogged my car, although it passed, but it had a very high NOx Level, almost.. almost failing. 430 is max, mine was 429

HC and CO levels were both good, lower than average listed at least. near zero at 25MPH

I smogged it in california ( bay area to be exact ) and the car was originally manufactured for florida ( so I think some emission components listed "california only" are not installed )

Well, the problem indicates engine burning too hot or pressure being too high, so
My guess for this problem:

Carbon deposite
restricted EGR
insufficent cooling
spark plug temperature too high? maybe?

However, there is one more thing, I hope some experienced mechanics out there can maybe varify for me:

I knew the mechanic who smogged my car, last time when he did my corolla ( I told him that it might not pass, but turned out it did ), he had a fan blowing in the front, this time he was busy, so he did without it. Could the fan be a problem? For insufficient cooling?

The Nox level decreased as speed increased, a.k.a 25MPH reading was lower than Idle

The car also shakes a little bit when idling ( needle doesn't jump around, just the car shakes, frequency varies alittle bit over time ). This might not even be relavent.

Thank you!
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Idle shakes could be a result of motor mounts (or even tranny mounts) needing replacement. I really don't know how to answer your first question. I've seen people who don't do oil changes, and simple stuff like replacing oil/filter/sparks/ignition/fuel filter/o2 sensors make differences.
What city are you from? im from the bay area too. I live in fairfield
look at the EGR system on the vehicle. most of the time the nox is related to the EGR or catalyst.
and I'm in Concord :) can the EGR be cleaned and reused ON A 96?
Yes it can, most of the time.

Easy way of removing the EGR tube, is to unbolt the egr from the intake manifold, then remove the distributor. You'll see the pipe from the EGR wide open, making it much easier to remove.
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