Date: Thu, 6 Dec 2007 14:22:12 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Emissions failures make me feel like a failure
In-Reply-To: <de48c0be0712060538n265f1231ja77f24e86b41e4f2@mail.gmail.com>
Content-Type: text/plain; format=flowed
I guess I also mis interpreted the numbers. NOX can only be tested for under
load. That is why we have the dyno testing. The Vanagon is NOx challenged as
it only has low compression, cupped pistons, retarded ignition timing and
the 3-way cat as NOx controls. Most other vehicles use exhaust gas
recirculation, (EGR). An excesively lean mixture agravates NOx as it raises
the peak flame temparature making more Nox and also does not leave enough CO
for the cat to reduce the NOx. That is why we have the O2 sensor. Check
the ignition timing to make it is properly set.
Dennis
>From: mordo <helmut.blong@GMAIL.COM>
>Reply-To: mordo <helmut.blong@GMAIL.COM>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Emissions failures make me feel like a failure
>Date: Thu, 6 Dec 2007 08:38:37 -0500
>
>Thanks for the input, people. I am interested to know more abnout standards
>around the country too. I'll search for some compendium of standards at my
>leisure.
>
>A few more items of note:
>
>
> 1. I am suspicious of a leak at the front of the cat - I'm not sure I
> got a good seal there even with two gaskets. I cannot detect a leak but
>the
> flanges are not parallel.
> 2. I had a light 1/4 tank of fuel when I went to test. I added about a
> liter of denatured alcohol just before driving 5 miles to the test
>station.
> 3. The engine was as hot as it ever gets without the fan coming on -
> just at the top of the LED.
> 4. It was about 30F and snowing at the time.
> 5. The exhuast pipe hose at the test station was almost flat - I don't
> know whether more flow or less would be better for my circumstance. The
> marginally intelligent woman operating it said "it don't matter."
> 6. The emissions test station literature suggests high NOx can be
> caused by a lean burn just as some of you suggest. However, the mix
>*seems*
> rich to me. Maybe a raw gas smell at the rear of the van suggests a
>tiny
> leak somewhere rather than a rich mixture? I certainly can't find a
>leak.
> 7. I have a spare ECU. Any point in swapping that out to see if it
> affects the running condition?
> 8. Is the typical mechanic equipped with any test devices that can
> measure what the emissions test station is measuring? I'd like to
>pre-test
> before going back.
>
>cheers,
>
>
>
>---------- Forwarded message ----------
>From: Scott Daniel - Shazam <scottdaniel@turbovans.com>
>Date: Dec 6, 2007 2:12 AM
>Subject: Re: Emissions failures make me feel like a failure
>To: vanagon@gerry.vanagon.com
>
>
>Other tips for passing -
>You want it as warm as you can get it. Keep it running the whole time, I'm
>not suggesting this, but disconnecting the rad fan sender will get it
>really
>warm temporarily at idle !
>
>Multi-electrode spark plugs - I have read of people reducing emissions
>for
>a smog test using those.
>I 'think' as you retard on timing NOx goes down, but too far and other
>things go back up.
>Always consider 'lean misfire' too as a cause of failing emissions
>results.
>
>Not sure what to do about it, but I've heard that mentioned many times.
>
>-----Original Message-----
>From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
>Tabe Johnson
>Sent: Wednesday, December 05, 2007 7:54 PM
>To: vanagon@GERRY.VANAGON.COM
>Subject: Emissions failures make me feel like a failure
>
>Your chart came out kinda funky on my screen, but it looks like
>you're failing on NOx. If that is the case, temporarily retard
>your timing by 5-10 degrees. That will lower the values enough
>to get you through.
>
>Could you please post emissions results when you do this? I'd
>like to know what the reduction actually is. I have data for
>another vehicle, but not for a WBX.
>
>
>tabe johnson / 87 westy
>
>
>
>--
>mordo
>1990 Carat
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