Date: Sun, 7 Oct 2012 21:01:27 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Smog test help
In-Reply-To: <5071FEA7.5090000@comcast.net>
Content-Type: text/plain; charset="US-ASCII"
Running those numbers most likely the cat is no longer good but that is not
your main problem. The CO-reading being the same at both those readings
indicates an O2 sensor problem. If the sensor itself is working then then
ECU may be getting tricked out by a wiring, most likely a grounding problem.
The O2 sensor reference shares a ground connection with the distributor. The
ground wire in the distributor harness is extremely important. On many 87-88
this ground connection was made at the base of the oil breather tower.
Plastic is not a good conductor. Move it! I usually move it to one the mount
screws for the fuel pressure regulator. Carefully inspect the crimp
connection. Replace it one of the shrink sealed connectors to stop the
continuing wire corrosion.
As a test, the green signal wire to the O2 sensor is a coaxial wire with an
outer shield which id grounded. Carefully expose the shield and check for
voltage between it and the chassis. Must be real close to "0". Any voltage
here gets added to the O2 sensor reference and effectively adds to the O2
sensor voltage the ECU is looking for. Higher voltage = richer mixture.
Now for the HC if the mixture does not fix it you will then need to look for
a miss fire or valve-engine problem. Get the mixture right first. Since you
didn't mention NOx I'll assume you don't have the dyno testing where you
are. You should be able to pass the CO-HC tests even with a bad cat. With a
good cat both 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: Sunday, October 07, 2012 6:14 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Smog test help
My 1988 Vanagon with 260K failed its smog check. I was wondering if someone
could point me in the direction of what to look to in order to better the
numbers and pass the test. The van has been sitting for a long time. I did
do an oil change and put in new plugs before the test.
One of the lifters was clicking loudly when I first ran the van for a number
of miles, and I noticed a fair amount of white smoke - water vapor? When the
engine idles it does smell a bit rich. The O2 sensor was changed about a
year ago and the cat is about 3 years old.
Here are the numbers
IDLE Test 1:
HC 432 (STD 220 )
CO 1.5636 (STD 1.0)
IDLE Test 2:
HC 315
CO 1.5527
Thanks
Todd
'88 Westy
