Date: Sun, 20 Sep 2009 15:38:16 -0700
Reply-To: Jake de Villiers <crescentbeachguitar@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jake de Villiers <crescentbeachguitar@GMAIL.COM>
Subject: Re: CA smog situation 84 1.9
In-Reply-To: <59943f850909201306x23a43424sa26cb793a0e1dcfe@mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Here's one from Dennis on smog;
Emissions issues really are straight forward for those who know how the
system works, what should happen normally, and what causes the various gas
failures. Results like you are the justification for emissions test
procedures and with your numbers you are definitely in the league of a
gross polluter.
For starters, in order for anyone to diagnose you problem, you also need
to state the CO amount. For diagnosing, you really want to measure the CO
before the catalyst. That is why there is a test port.
I'll go over the gasses again and if someone wants, feel free to post this
on the Wiki.
Carbon Monoxide is the result of incomplete combustion due to insufficient
oxygen being available or combining with the fuel to complete the burn.
Yes, this is the one that is mixture, and temperature related. Why
temperature? The big un-vaporized fuel molecules may not get the oxygen
even if it is available. That is why there are winter fuel blends and we
need enrichment to get cold engines started. If the CO is in limits, the
fuel injection is basically working. The Vanagon should be able to get
near 1% even before the Cat.
Excessive Hydrocarbons. This is fuel that never started to burn or get
ignited. Yep, raw gas out the pipe. Usual causes are ignition miss fire,
leaking valves, rings, etc. Another phenomenon here is what is known as
the "Lean" miss fire. This is due to slight differences in mixture amongst
cylinders with the leaner one failing to "light up". This is that crazy
intermittent miss that can drive you crazy. The Vanagon engne is really
prone to this due to the poorly designed intake system. Over advanced
ignition timing will also add to this as the advance timing will require
much less air and fuel to maintain a low idle speed. This results in poor
swirl and mixing and the fuel mix will fail to light. If an oil change
fixes this, consider you have a ring or valve-guide problem. Excessively
lean or rich mixtures will result in the miss fire.
Oxides of Nitrogen (NOx). This is the result of excessive flame
temperatures. Engine design, ignition timing, and load all add to create
this. The controls are timing settings (why we have the dual diaphragm
distributors before Digifant), low compression, most vehicles EGR, and in
everything 81 and later the three way oxidation reduction catalyst with
the O2 sensor for final mixture control. The downside of this is that we
can no longer use lean mixtures to improve fuel economy. This is also a
major problem with Diesel engines as they have high compression, and lots
of excess air.
And the rest from that thread;
Yes!
All aftermarket cats including the Emicco do not work as well or last as
long normally as OEM. They do not have the volume, and surface area of
active material. That said, Cats do not die, they are murdered. At 400 PPM
HC going in even an OEM one did not stand much of a chance at long life.
Your compression readings are low but there could be many causes. I have
learned not to make conclusions on compression tests alone unless
something is broken. You also need to do a leak down do determine of you
have a ring or valve issue. I think proper setting will get it somewhat
cleaned up for you.
Here in NY we get smogged every year and the limits for our vans is 120
ppm HC and 1.2% CO.
On Sun, Sep 20, 2009 at 1:06 PM, Leonard Anthony <whitewatering@gmail.com>wrote:
> Hi Volks,
>
> Here are the numbers:
> %CO2 Idle 12.64 2500 rpm 14.56
>
> % O2 Idle 3.0 2500 rpm 0.4
>
> HC Idle 94 ppm Max 120 (pass)
>
> *HC 2500 rpm 169 ppm Max 150 (fail)*
>
> CO idle 0.00 pass
> CO 2500 rpm .02 pass
>
> Compression 150 on all 4
>
>
> I now seem to be able to search the archives, and found some great help
> from
> some of Dennis Haynes (he's awesome) posted answers, but could not find his
> write up article that is supposed to be out there somewhere. If anyone has
> it and could send it to me that would be great, although from what I
> gleaned
> I think I have a lean miss-fire. Possibly an ignition issue but I'm more
> suspecting a small intake leak or sticky or bad valve. I do have a
> misbehaving lifter, I'm wondering if it could be causing the valve problem?
> So I'm guessing my next step - replace the lifter, check again for leaks,
> then do a leak down test. Never done a leak down test but found out how in
> the archives (Thanks, Dennis). In 30 years of driving, (mostly Japanese
> cars) never needed one! Blessed be my 90 Pathfinder with 330,000 miles
> still
> going strong.
>
> I also noticed that my maximum limits seem to be set lower that other CA
> list members vanagon smog tests. Most posts report California limits for
> HC's idle as 150 idle & 180 @ 2500 rpm. (I would have passed!). Does
> anyone have a recent test they can look at to see if they lowered our
> limits? I've read somewhere that our vans need to be put on the test as a
> truck, rather than a passenger vehicle. At the top of my test it was put in
> as a passenger vehicle. DMV confirmed it is a truck, but the BAR guy said
> it
> doesn't make a difference because the machine only really sees the VIN.
> Although it would seem a good running engine should be within the 120/150
> that I seem to be held to anyway, but It would seem that we should be all
> held to the same standard.
>
> from my post yesterday I have had some good responses on how to squeak by,
> (Thanks everyone)! but I'm still wondering about my sudden lifter
> failure/evacuation. Does this ever happen on these engines? I'm worried
> there might be more something more substantial going on, such as a seat
> problem. Any thoughts?
>
>
> Thanks!
> Leonard
>
--
Jake
1984 Vanagon GL
1986 Westy Weekender "Dixie"
Crescent Beach, BC
www.thebassspa.com
www.crescentbeachguitar.com
http://subyjake.googlepages.com/mydixiedarlin%27
