Subaru XT 1988 Service Manual page 131

,
\
~,
2-1
EMISSION CONTROL SYSTEM AND VACUUM FITTING
System Application
There are thr.ee emission control systems which are as follows:
1) Crankcase emission control system
2) Exhaust emission control system
• Ignition control system
• Front catalyst (Three-way catalyst)
• Rear catalyst (Oxidation catalyst)
3) Evaporative em ission control system
General Precautions
1) Know the importance of periodic maintenance services.
(1) Every service item in the periodic maintenance
schedule must be performed.
(2)Failing to do even one item can cause the engine to run
poorly and increase exhaust emissions.
2) Determine if you have an engine or emission system
problem.
(1) Engine problems are usually not caused by the emis-
sion control systems.
(2) When troubleshooting, always check the engine and
the ignition system first.
2
3) Check hose and wiring connections first.
The most frequent cause of problems is simply a bad Connec·
tion in the wiring or vacuum hoses. Always make sure that
connections are secure and correct.
4) Avoid coasting with the ignition turned off and prolonged
engine braking.
5) Do not damage parts.
(1) To disconnect vacuum hoses, pu II on the end, not the
middle of the hose.
(2) To pull apart electrical connectors, pull on the con-
nector itself, not the wire.
(3) Be careful not to drop electrical parts, such as
sensors, or relays.
I f they are dropped on a hard floor, they shou Id be
replaced and not reused.
(4) When steam cleaning an engine, protect the distribu-
tor, coil, air cleaner, and throttle body from water.
(5) When checking continuity at the wire connector, the
test bar should be inserted carefully to prevent terminals
from bending.
6) Use SUBARU genuine parts.
7) Record how hoses are connected before disconnecting.
(1) When disconnecting vacuum hoses, use tags to
identify how they should be reconnected.
(2) After completing a job, double check to see that the
vacuum hoses are properly connected. See the "Vacuum
connections label" under the hood.