Failed emissions due to timing? Can it be?

[Dave Haupt]

I'm guilty of providing incomplete information.  The
exhaust gas test was fine, with some readings very
close to zero, and the highest one only 20% of the max
it's allowed to be.  The failure was purely on the
tech's claim that the ignition timing was off by five
degrees.

Dave

--- Alan Cordeiro <alancordeiro at comcast.net> wrote:
> Dan,
> 
> Not sure I understand where the five degrees could
> come from.
> 
> 1)  The crankshaft pulley can only go on one
> way...not sure how
> it could go off by five degrees.
> 
> 2)  If the pulley were off five degrees somehow, you
> still end up aligning
> the timing marks on the CAMSHAFT pully to the
> (rusty, almost invisible)
> timing mark on the flywheel. The engine reads the
> flywheel teeth and
> once-per-revolution pin, and uses this as the basis
> of timing.
> therefore, if your timing check was good....the
> front crankshaft position
> should not matter at all.
> 
> Alan
> 
> > I haven't experienced this first hand, but isn't
> it pretty common for
> > the front pulley to slip out of alignment? I
> thought I've heard many
> > people doing TB jobs and found the TDC reference
> had moved notably. It
> > could be that yours has slipped 5°. Just a thought
> anyway.
> >
> > While improper timing can certainly give poorer
> emissions, you didn't
> > mention if your car passed (or was tested yet).
> Could be your timing is
> > fine with the pulley slipped, or it could be the
> ignition is being
> > retarted by the ECU too. Perhaps it's falsely
> detecting knock?
> >
> > -- 
> > Dan Cordon
> > Mechanical Engineer - Engine Research Facility
> > University of Idaho
> >
> > _______________________________________________
> > 200q20v mailing list
> > 200q20v at audifans.com
> > http://www.audifans.com/mailman/listinfo/200q20v
> 


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