Did you search the list archives?

 >>CA Smog Failed - 1985 1.9L<<  was a thread in late June of this
year, Dennis Haynes gave a good explanination of why & what with
regards to the emission testing.

Rob
becida@comcast.net

At  10/18/2008 02:03 PM, John C... wrote:
>Hi All,
>
>Yup, my new (to me) 87 Syncro 2.1 Failed Emissions ( for the 3rd time) !!!
>
>Readings: ( and the third test was Way worse than the first two ) !!!
>
>What I did between the 2nd test & the 3rd test
>was to get the bus out on the freeway
>& hit it hard for about 50 miles.
>Kicked the cat many times
>ran out the gas & put premium in it.
>but readings got worse ???
>
>RPM: 991     %CO2: 11.8      %O2: 3.3    HC: 788   CO(%): 1.53     FAIL
>
>RPM: 2511   %CO2: 13.5      %O2: 1.6    HC: 203    CO(%): .88      PASS
>
>I've changed oil (with 1qt Marvel), filter, air filter.
>Plugs, plug wires, rotor, cap
>
>I now have an O2 sensor, & Cat on the way.
>
>My question is;
>Will the old muffler affect Emissions?
>Should it be replaced as well?
>
>Bus runs quiet enough & I'm going to put a subbie in soon.
>
>What can I do to the MAFM? (clean? adjust somehow?)
>Timing? (retard)?
>
>Any & all help much appreciated !!!
>
>thanks,
>John C...
>
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>10/17/2008 7:01 PM