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Emissions Test Notes
Last Updated: 11/16/2010
Author: Skip

We just got a great email that prompted this new section regarding emissions testing - always a challenge for an older car.  Hopefully, we'll be able to add more tips as they become available.  Feel free to drop us an email at

From: "Herman, Russ
Sent: Thursday, November 20, 2003 5:10 PM
Subject: Texas Emision Test

I just experienced the pleasure of the new Texas annual inspection.  The
basic safety inspection was a breeze as always while the emissions test
was a problem.  The computer is loaded with all the various cars,
engines, etc. and tells the technician how to run the test.  The
dynamometer test is done at 15 and 25 mph. The parameters for my 1986
951 (121K miles) indicated second gear for the 15 mph test and third for
the 25 mph test.  I failed both tests due to high hydrocarbon levels by
a healthy margin at 15 mph but was closer at 25 mph.  I asked the
technician about the gears suggested as the RPMs which tie to these
speeds are at levels well below how the car is to be driven.  We reran
the tests at 15 mph in first gear and at 25 mph in second gear being
careful not to exceed 2500 RPM as specified by the test.  In the
appropriate gears and at realistic RPMs, I passed both tests by a
considerable margin.  I hope this helps someone else to save an unneeded

Russ Herman

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