Date: Mon, 14 Apr 2003 21:51:22 -0700
Reply-To: Tom Young <tomyoung1@ATTBI.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tom Young <tomyoung1@ATTBI.COM>
Subject: Re: 82 Failed CA Smog Test- help!
Content-Type: text/plain; charset="iso-8859-1"
----- Original Message -----
From: "S.Harrison" <diverseimaging@EARTHLINK.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Monday, April 14, 2003 9:02 PM
Subject: 82 Failed CA Smog Test- help!
> 82 Vanagon Westy. 89K on original engine.
>
> Took it to a local garage that is certified to smog test vehicles up for
the
> CA biennial inspections. Drove it for a about 2 hours prior so it was good
> and warmed-up.
>
> I passed all aspects of the test but the CO% at idle -- I was at 5.56%,
with
> a maximum allowable of 2.00. The CO% at 2500 RPM measurement was fine,
about
> 0.62%.
>
> So what could help? I'll be changing the oil and filter, installing new
> plugs, cap, rotor, and points before the next check, but any ideas on how
I
> can lower the CO percentage?
> Could the AFM be at fault?
Yes.
> Leaky injector seals?
Yes.
All you mention, and much, much more could be the source of your problem.
You're on the right track by first making sure the ignition system is in
tip-top shape; be sure and set the timing and idle while you're at it. You
might also set the idle at the top end of the specified range since
increased RPM's tend to help here. Next, start checking things: fuel
pressure, injector seals, leaking injectors (including cold start), TempII
sensor, and so forth. All these things can be checked using fairly simple
tools and equipment. The AFM is a little tougher since you don't have (I'm
guessing) an O2 sensor. Over time the spring in the AFM weakens, leading to
richer running. It can weaken so much that even adjusting the idle mixture
control full lean won't be enough. The spring inside the AFM can be
tightened to compensate and that's usually accomplished by monitoring the O2
sensor output as you tighten until you get it back into the right range. I
suppose if you're using a "pass or don't pay" sort of place you can just
keep trying until you get it right, but it might be better to take it to a
shop with an exhaust gas analyzer (make sure they use the port, not the
tailpipe) and have them set it correctly after you've done everything else.
---------------------------------------------------------------
Tom Young '81 Vanagon
Lafayette, CA 94549 '82 Westfalia
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