GxT Ferret 54 ENGINE DIAGNOSTIC CENTER - Manual (Page 76)

TESTING EMISSIONS
Visual Inspection
Before undertaking diagnosis of any problem,
always conduct a careful visual inspection of
all hoses and wiring connections. About half
of all complaints are caused by simple
physical problems. Much time is wasted
performing high-tech diagnostics, only to
discover that the problem was the result of
a poor or missing connection. The
Visual
Inspection choice in the REPORT-
AUTOTEST menu provides a means of
marking various defects or conditions that
may be found during an inspection.
Engine Analyzer
Once you are satisfied that everything is
physically connected, verify the proper
operation of the ignition system. Once any
problems have been identified and corrected,
you are ready to perform a gas analysis.
Vehicle O2 Sensor
Many emissions and driveability problems
arise from ‘lazy’, contaminated or defective
vehicle O2 sensors and their connections.
Verifying the proper operation of the O2
sensor first can save valuable diagnostic
time.
Gas Analyzer
A gas analyzer is indispensable for ensuring
a vehicle meets state and federal emission
guidelines, but, if that is all it is used for, a
valuable diagnostic tool is going to waste.
Many driveability problems that are difficult
or impossible to diagnose with other tools
may be uncovered by analyzing the content
of exhaust emissions.
Preparing for tests
Before conducting tests, both the Gas
Analyzer and the engine must be allowed to
warm up. Gas Analyzer warm-up will take
from 5 to 15 minutes, depending on outside
temperature and the time since last use.
Apply power to the Diagnostic Center first,
so warm up can begin while you route hoses
and connect leads. Normally, the Gas
Analyzer will be warmed up in about the
same time it takes to warm the engine.
Because the converter can oxidize significant
amounts of CO and HC, the best readings
will be obtained by preconditioning the
engine.
Once the engine and converter are at
operating temperature, stop the engine. The
converter will cool more quickly than the
engine. After about ten minutes the engine
may be restarted and tests performed.
Readings should be taken within about two
minutes, before the converter becomes
active again. Disable the air pump or
aspirator to help delay reactivation of the
converter. The manufacturer’s instructions for
preconditioning the engine for emission
testing should be followed if they differ from
these instructions. In any case, always warm
the engine before placing the probe in the
tailpipe.
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