Impco HHI, Service Manual

Page: 462 / 485

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1. Install Oxygen Sensor. Torque to 36.2-43.4
ft. lbs. (49.0-58.8 Nm)
2. Reconnect electrical connector to the Oxygen
Sensor.
3. Reconnect the negative battery cable.
4. Start the vehicle and let run until it reaches
normal operating temperature.
5. If a DTC code is found, refer to the Electrical
Section for further diagnosis.
IX. MIXER/ADAPTER/THROTTLE BODY &
RELATED SEALS
REMOVAL PROCEDURE
1. Disconnect the negative battery cable.
2. Relieve the LPG fuel system pressure. Refer to
III. LPG Fuel System Pressure Relief.
3. Remove the air intake duct.
4. Remove the retaining pin holding the fuel hose
fitting and remove fuel hose.
Residual vapor pressure will be present in
the fuel system. Ensure the work area is
well ventilated before disconnecting any
fuel line.
5. Remove the two hoses on the side of the Mix-
er.
6. Remove electrical connector on Throttle Body
7. Remove the four screws under the Mixer that
secure the Mixer, Adapter and Throttle Body.
8. Remove the Mixer and Adapter.
9. Remove Throttle Body.
INSTALLATION PROCEDURE
1. Lightly lubricate new O-rings with Vaseline or
petroleum jelly prior to installation.
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 as-
sembled using silicone lubricants. Always
use “oxygen sensor safe” RTV sealant for
repair procedures. Silicon contamination
will cause a high but false HEGO signal vol-
tage (rich exhaust indication). The ECM will
then reduce the amount of fuel delivery to
the engine, causing a severe driveability
problem. If silicone contamination is sus-
pected, remove and visually inspect the
sensor element. If contaminated, the por-
tion 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.
2. Place new O-rings on top of the Throttle Body.
3. Place Gasket and Throttle Body on intake adap-
ter.
4. Place Adapter and Mixer on top of Throttle Body
and align screw holes. Secure with the four re-
taining screws and
Torque to 80 in.lb. (9 Nm).
5. Install the fuel hose fitting into the Mixer and hold
with the retaining pin.
6. Install the air intake duct.
7. Install the two hoses to the 90° fittings on Mixer.
8. Reconnect the negative battery cable.
9. Open LPG tank valve.
10. Turn ignition to ON for approximately 30
seconds, then OFF.
11. Leak check the LPG fuel system at each ser-
viced fitting.
12. Start the vehicle and leak check the LPG fuel
system at each serviced fitting.
13. Test drive vehicle to ensure it operates correctly
at all throttle ranges. If a DTC code is found, re-
fer to the Electrical Section for further diagnosis.
X. CRANKCASE VENTILATION SYSTEM
INSPECTION/DIAGNOSIS
RESULTS OF INCORRECT OPERATION
A plugged positive crankcase ventilation (PCV) ori-
fice or hose may cause the following conditions:

Rough or unstable idle