Date: Sun, 2 Mar 2014 23:35:19 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Fail air are
In-Reply-To: <E0314C76-96AE-47DC-AB9F-258827411FBA@telus.net>
Content-Type: text/plain; charset="us-ascii"
This helps a lot. Your first step has to be to correct the idle issue. The
hydrocarbons are the result of a failure to burn the fuel in the first
place. At idle, from an adjustment stand point the ignition timing may be
over advanced. This will cause excessive HC as there is not enough air flow
and swirl for the fuel to properly burned. Sounds counter-intuitive as
advancing the timing makes the engine run smoother and more responsive but
there are reasons for the specs to be where they are.
The next common causes for excessive HC is a miss fire, either ignition or
fuel related. Un even fuel delivery such as a bad injector or a vacuum leak
at an injector seal or other place in the manifold will cause this.
A bad valve or worn guides can also cause the excessive HC especially at
idle. Time for a compression and leak down test. Intake valve problems are
common. They are especially troublesome as they not only effect the one
cylinder but they contaminate the intake tract with both air and some
combustion gasses.
For your O2 sensor the CO readings indicate the system is not in full
control. This could be caused by a bad sensor or a wiring problem. Most
notable for this slightly high reading may be a bad ground. The high idle HC
will trash an O2 sensor and the catalyst in short order. The CO reading also
indicates the Cat is already shot.
A competent emissions person will test the emissions before and after the
cat. Ideally you want to see ~.5% CO before and HC should be well under 200
ppm on a warm engine. After the cat should be near 0 for both, even at idle.
Hope this helps.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Alain Thibault
Sent: Sunday, March 2, 2014 11:07 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Fail air are
Dennis
Actually the hydrocarbons were very high at the Idle test (1025) but below
the maximum allowable for the driving test (73.00)... As for the CO, it
passed at 0.82 and .078 at both tests (driving and idling ) and so it was
for the NOx at both tests, that is ...well below what is allowed. So all
together, everything was ok except the hydrocarbons at the idle test...Does
it help?
Alain
Westy 1986
Sent from my iPad 2
