14
Inspect Air cleaner element according to the
Recommended Maintenance Schedule found
in this section.
Check Fuel lines for cracking, splitting or chaf-
ing. Replace if any of these conditions exist.
Verify Throttle body return action to ensure
throttle shaft is not sticking. Repair if neces-
sary.
Check for leaks at the throttle body and intake
manifold.
PRESSURE REGULATOR MAINTENANCE AND
INSPECTION
IMPORTANT:
The Pressure Regulator components have been
specifically designed and calibrated to meet the
fuel system requirements of the emission certified
engine.
If the Regulator fails to operate or develops a
leak, it should be repaired or replaced with the
OEM recommended replacement parts. When
inspecting the regulator check for the following
items:
Check for any fuel leaks at the inlet and outlet
fittings.
Check for any fuel leaks in the regulator body.
Check the inlet and outlet fittings of the coo-
lant supply lines for water leaks.
Check the coolant supply lines for hardening,
cracking, chafing or splits. If any of these con-
ditions exist replace coolant lines.
Check coolant supply hose clamp connec-
tions, ensure they are tight.
Check to ensure the Regulator is securely
mounted and the mounting bolts are tight.
Check the Regulator for external damage.
Check the Regulator electrical connections to
ensure the connector is seated and locked.
EXHAUST SYSTEM AND CATALYTIC
CONVERTER INSPECTION AND
MAINTENANCE
IMPORTANT:
The exhaust system on this emission certified en-
gine contains Heated Exhaust Gas Oxygen
Sensors (HEGOs) which provide feedback to the
ECM on the amount of oxygen present in the ex-
haust stream after combustion.
The measurement of oxygen in the exhaust
stream is measured in voltage and sent to the
ECM. The ECM then makes corrections to the
fuel air ratio to ensure the proper fuel charge and
optimum catalytic performance. Therefore, it is
important that the exhaust connections remain
secured and air tight.
Contamination of the HEGO sensor can re-
sult from the use of an inappropriate RTV
sealer or silicone spray products. Do not use
silicone sprays or hoses which are assem-
bled using silicone lubricants. Always use
“oxygen sensor safe” RTV sealant for repair
procedures. Silicon contamination will cause
a high but false HEGO signal voltage (rich
exhaust indication). The ECM will then re-
duce the amount of fuel delivery to the
engine, causing a severe driveability prob-
lem. If silicone contamination is suspected,
remove and visually inspect the sensor ele-
ment. If contaminated, the portion of the
sensor exposed to the exhaust stream will
have a white powdery coating. Always be
sure to eliminate the cause of contamination
before replacing the sensor.
When inspecting the Exhaust system check the
following:
Exhaust manifold at the cylinder head for
leaks and that all retaining bolts and shields (if
used) are in place.
Manifold to exhaust pipe fasteners to ensure
they are tight and that there are no exhaust
leaks repair if necessary.
HEGO electrical connector to ensure connec-
tor is seated and locked, check wires to
ensure there is no cracking, splits chafing or
“burn through. Repair if necessary.
Exhaust pipe extension connector for leaks
tighten if necessary.
Visually inspect converter to ensure muffler is
securely mounted and tail pipe is properly
aimed.
Check for any leaks at the inlet and outlet of
the converter.
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