Again the OBDII systems test many of the systems. They know if a catalytic converter goes bad or even if there is a cylinder misfire. Even if the miss fire is due a to a bad injector, vacuum leak, or an engine problem, the system will know. While hydrocarbons from leaky vapor recovery systems are a common failure the NOx reduction is an extremely important part of smog control. This is why the dyno tests were needed as an engine has to be loaded to produce the NOx in order to test the reduction controls. Many cars use exhaust gas recirculation as a control. Most VWs including the vanagon do have EGR so they must rely on the engine producing less and the 3-way catalyst taking care of what is produced. Dennis
-----Original Message----- From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of James Sent: Sunday, March 2, 2014 11:34 PM To: vanagon@GERRY.VANAGON.COM Subject: Re: Oil pressure warnings, WAS: Mann Oil Filter and lifters Actually, they're trying to 'save us money' - the new test, that won't work if the 'idiot light' is on, only involves using the OBDII port - no tail pipe sniffer at all! It is thus $20 cheaper than the old test (which those of us who have vehicles like our '91 Vanagon still have to do, as there's no OBDII to plug into). I just had the 2003 Matrix in for it's test last week, and was filled in by our local mechanic on all the ins and outs of the new test. Supposedly the leading cause for the check engine light to be on here is a failure of the evaporative emissions control system, and it's those stray hydrocarbons that they're most worried about - makes sense, carbon monoxide isn't nearly as serious a pollutant as the various aromatic hydrocarbons in gasoline are. James Ottawa, ON |
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