Re: B2200 Emissions Problem...

Douglas,
Hi NOx is almost always caused by higher than normal combustion temperature.
The higher than normal combustion temperature is what enables the reaction
to take place which forms NOx.  The most common causes would be over
advanced ignition timing or a mechanical problem that would cause the timing
to be too far advanced such as a seized mechanical advance unit.  Another
common problem is an inoperative EGR system since putting a metered amount
of exhaust gases in with the air fuel mix also keeps combustion temperatures
down.  An overly lean air fuel mix also causes elevated combustion
temperatures.
--
"They that can give up essential liberty to obtain a little temporary safety
deserve neither liberty nor safety"

Benjamin Franklin
"Douglas S. Ladden" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Hello everyone!
>
>     I was hoping someone might be able to give me some ideas as to what
> might be causing an emissions problem I seem to have.  The vehicle is a
> 1990 Mazda B2200 with Fuel Injection in California.
>
>     The CO and HC emissions are incredibly low, almost non-existant,
> which is great, but the NOx emissions are incredibly high, nearly twice
> the max limits.  Any ideas as to what I should be looking for or how to
> fix this problem would be very appreciated.  Thanks!
>
> --Douglas