Date: Fri, 31 Dec 2010 00:04:19 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Failed emissions testing
In-Reply-To: <4D1D52AB.3020009@comcast.net>
Content-Type: text/plain; charset="us-ascii"
Over the years I have responded to emissions issues many times. There should
be some good info in the Archives.
I am assuming this is only an idle test. It makes a huge difference if this
is a 2,500 rpm test.
The 1.43 CO tells me the O2 sensor or circuit is not working or so many
other things have been tampered with/miss adjusted that it cannot
compensate.
The O2 sensor circuit should regulate the mixture around .5 CO even before
the Cat. This alone will also bring down the HC. If the CO was within normal
limits then excessive HC could be the result of an ignition miss, incorrect
timing, idle speed, or a valve/engine problem. If the injectors are slightly
out of tolerance or the engine has some issue a correct overall mixture can
result in one or more cylinders running lean causing what is known as a lean
miss fire. This lean miss will result in excessive CO.
Test the O2 sensor, a digital voltmeter will do wonders here.
Check timing and idle speed settings. Avoid temptation to advance the timing
to make the engine smoother or more responsive. The advanced timing will
reduce the amount of air/fuel needed for the given idle speed increasing
both the CO and HC. Cheat just a little on idle speed, 950-1,000 rpm no
load.
To test the cat have the CO measured before and after. With a properly
working cat and all other engine issues CO and HC should be near "0".
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Todd.Last
Sent: Thursday, December 30, 2010 10:49 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Failed emissions testing
I went to have my Westy emission tested today, and it failed the test.
The van had been sitting for a number of months, and when I first
started it, It sounded like one lifter was devoid of oil. I let it run
for awhile and the noise went away.
I'm not sure, but it looked like the oil was a bit overfilled as well.
Anyway my numbers were (at idle)
270 HC (Max allowed is 220)
1.43 CO (Max allowed 1)
Any suggestions on what to adjust to try again?
thanks,
Todd
'88 Westy
