G420E/G424E
Tier
LP Engine
Maintenance Schedule
34
Inspect for Intake Leaks
z
Visually inspect the intake manifold, throttle
assembly (D), and manifold adapters (E), for
looseness and leaks. Repair as necessary.
(D) Throttle Assembly (E) Manifold Adapter
(F) TMAP Sensor
Inspect Throttle Assembly
z
Visually inspect the throttle assembly motor
housing for coking, cracks and missing cover-
retaining clips. Repair and/or replace as
necessary.
NOTE
Refer to the LP mixer and throttle section
of the service manual for procedures on
removing the mixer and inspecting the
throttle plate.
Checking the TMAP Sensor
z
Verify that the TMAP sensor (F) is mounted
tightly into the manifold adapter (E), with no
leakage.
z
If the TMAP is found to be loose, remove the
TMAP retaining screw and the TMAP sensor
from the manifold adapter.
z
Visually inspect the TMAP O-ring seal for
damage. Replace as necessary.
z
Apply a thin coat of an approved silicon lubricant
to the TMAP o-ring seal.
z
Re-install the TMAP sensor into the manifold
adapter and securely tighten the retaining screw.
Inspect Engine for Exhaust
Leaks
z
Start the engine and allow it to reach operating
temperatures.
z
Perform visual inspection of exhaust system.
z
Repair any/all leaks found.
Replace Oxygen Sensor
1.
Stop engine and wait until the exhaust pipe and
exhaust pipe is cooled.
2.
Disconnect the electrical connector of oxygen
sensor.
3.
Remove oxygen sensor.
4.
Assemble new oxygen sensor.
Tightening torque : 45 N•m (32.5 lb•ft)
5.
Connect the electrical connector of oxygen sensor.
F
E
D
