In an earlier post I asked why I was getting a 2-3 mpg decrease in mileage after a tuneup and O2 sensor change. Here's an update: The engine does not seem to be running rich. Tailpipe deposits are dark gray, not black. Went for emissions testing today, passed with flying colors. HC was 8ppm at idle and at 2500 rpm, better than my test a year ago. HC would be higher if van was running rich, right? CO readings were also lower--at idle CO was 0 ppm. Does this seem odd? O2 sensor is working and is not grounded or anything. I can attach a voltmeter and watch it do its thing as the ECU adjusts mixture. Another variable I neglected to mention is that I installed a new syncro-style air filter when I did the tuneup. The old air filter was also the syncro style. That's all for now... Mark McCulley 87 syncro Westfalia |
Please note - During the past 17 years of operation, several gigabytes of
Vanagon mail messages have been archived. Searching the entire collection
will take up to five minutes to complete. Please be patient!
Return to the archives @ gerry.vanagon.com
The vanagon mailing list archives are copyright (c) 1994-2011, and may not be reproduced without the express written permission of the list administrators. Posting messages to this mailing list grants a license to the mailing list administrators to reproduce the message in a compilation, either printed or electronic. All compilations will be not-for-profit, with any excess proceeds going to the Vanagon mailing list.
Any profits from list compilations go exclusively towards the management and operation of the Vanagon mailing list and vanagon mailing list web site.