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Date:         Fri, 19 Jul 2013 20:19:26 -0400
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 for third time-Some helpful hints.
Comments: To: David M <covrambles@YAHOO.COM>
Content-Type: text/plain; charset="iso-8859-1"

The air temperature sensor was never readily available as a separate part. I have never seen one go bad. It is part of the air flow meter and it does very little for the operation of the engine. Basically air temperature is a consideration for determining the actual mass of the air at a given volume flow rate. Colder air is denser. Anyway, a replacement AFM will have this part. After the engine is warmed up and the ECU goes into "closed loop" operation the O2 sensor should be the ultimate control. The AFM then deals with speed and throttle "changes", closed throttle engine being overrun and full throttle. The AFM mixture screw is only effective near idle and if any long term change is made to mixture then something is really too far out of range for the O2 sensor system to compensate or O2 sensor is not working. The throttle switch is very easy to check, is available. Even if you can’t get the assembly the micro-switch itself is available at good electronics suppliers and a harness can be made to connect it. Usually it just needs to be adjusted except on the 1.9L engine where someone has swapped the connectors with the warm up regulator instantly destroying the switch. For the coolant temp sensor there are two, one for the ECU and one for the gauge. When the ECU sensor goes bad the usual problem is starting and cold idle, especially in warm weather or hot re-starts. If it starts, runs, and goes into closed loop "O2 sensor control" that sensor is fine. Most of the time a problem sensor is really a connection or ground issue. I have fixed many by re-seating or replacing the connector. And check those ground wire connections!

NOx is produced during the combustion process under certain pressure, (load) and internal temperature, (peak flame temperature), conditions. That is why the test is done on the dyno. The only tools the Vanagon engine has to control NOX is the low compression and the moderate ignition timing curve. Proper timing is extremely important. If it is over advanced which some folks do to make the engine more responsive or to run smoother excessive NOx will be the result. Also, a rich mixture reduces, not increases the formation NOx. Also, make sure you have the correct spark plugs. Too high a heat range or the wrong protrusion into the combustion chamber can have a bad effect. The water boxer does not have an EGR system as many engines do to reduce or control NOx. As for after treatment, the Catalyst is the device to reduce the NOx along with unburned hydrocarbons and carbon monoxide. This is why it is called a three way cat! Now in order for this to work very tight mixture control is required by the O2 sensor. As these reactions require both an oxidizing (reduce HC and CO) and reduction (NOx) the O2 sensor has to constantly switch from rich to lean, otherwise known as crossover. If the sensor is not working the cat can't do its job and can also be damaged.

Contact your state DMV and see what the requirements are for getting an extension. It may be easier than you think. It is probably based on if repairs are going to cost over $XXX or you have already spent $XXX you can get an extension until the next cycle.

From experience you probably have a bad catalytic converter.

Dennis

-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of David M Sent: Friday, July 19, 2013 7:16 PM To: vanagon@GERRY.VANAGON.COM Subject: Re: Failed emissions for third time

The shop is called German Autotec on Main St in Mesa. I jsut spoke to them on the phone. They said they connected a diagnostic tool to the ECU (he called it a ';break-out box') and it indicates the coolant temperature sensor, the throttle switch, the AFM and the air-temperature sensor are bad. He quoted me $450 plus $50 labor just to replace the AFM. The throttle switch and air temperature sensor he said are no longer available.

Not sure what to do now. He said he'll charge me $150 for the diagnostic work so far and of course I've paid $55 in emissions testing fees. My registration expired at the end of June.

David

________________________________ From: Karl Wolz <wolzphoto@q.com> To: 'David M' <covrambles@YAHOO.COM>; vanagon@GERRY.VANAGON.COM Sent: Friday, July 19, 2013 1:56 PM Subject: RE: Failed emissions for third time

Who are you taking the van to?  Were the readings before the cat significantly different than those after?

I'd suggest taking it to Import Car Specialists at 16th St and Indian School - 602-265-6412 - talk to Ray, Or Myer's European on McClintock and McKellips.  Their # is 480-946-5200.

Good luck,

Karl Wolz

|-----Original Message----- |From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] |On Behalf Of David M |Sent: Friday, July 19, 2013 1:15 PM |To: vanagon@GERRY.VANAGON.COM |Subject: Failed emissions for third time | |I posted a while back about my 1987 Vanagon failing the AZ |emissions on CO and NOX levels. |The place I took it to said it was running rich and they |adjusted the timing and mixture. Then they told me to drive it |50-75 miles on the freeway to 'clean out the exhaust'. Well I |did that and took it back in and they put it on their exhaust |analyser. They said it should pass now so I had it retested |(free) and it failed on CO and NOX again. CO and NOX were down


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