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Diagnostics
Exhaust gas analyzers can be used to diagnose driveability concerns, ignition system
problems, fuel management issues, engine mechanical problems, excessive emissions prob-
lems and many other vehicle systems. Vehicle inspection and preparation are the keys to
getting the most out of your gas analyzer.
1. A visual inspection should include; vacuum hoses, air filter, exhaust system,
air management system, emission related components, etc. If the malfunction
indicator light (MIL) is illuminated, check the diagnostic trouble codes (DTC’s)
prior to testing.
2. Vehicle preparation:
a. The engine should be at operating temperature prior to testing.
b. Start the engine and run until the cooling fan cycles on and off. Another
option is using a scan tool to check the engine coolant temperature (ECT).
The temperature should exceed 190 degree F.
c. After the engine is warm, increase the engine speed to 2500 RPM for
approximately 60 seconds.
d. Return the engine speed to idle.
e. Insert the sample probe and begin your diagnostics.
Understanding the relationship of exhaust gases will enhance your ability to diagnose
driveability issues. The Exhaust Gas Relationship Chart will provide a few suggestions:
Exhaust gas analyzers can be used to diagnose other vehicle systems. Here are a few
suggestions:
1. Evaporative emission system operation.
2. Evaporative emission system leaks.
3. Fuel oders in and around the vehicle.
4. No-Start conditions.
5. Engine combustion gases in the cooling system.
6. Air injection emission systems.
7. Exhaust system leaks.
8. More...
