Impco HHI, Service Manual

Page: 470 / 485

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over the valve pin and install C-clip or retain-
ing clip.
4. Place a new secondary body gasket ensur-
ing the small hole in the gasket is aligned
with the small hole in the body cover. Place
body cover and gasket on the front of Regu-
lator body, ensuring the holes in the gasket
are aligned with all screw holes.
5. Set new primary diaphragm the face of the
body cover using the screw hole for proper
alignment.
6. Place the Regular face over the diaphragm
and hand thread all seven screws through
the face plate and body cover into the Regu-
lator body.
Torque the screws to 4.5 Nm
(40 in. lbs.) in a criss-cross pattern.
7. Using side-cutters, cut off the nose of the
soft secondary seat and remove from sec-
ondary lever.
8. Push the nose or button of the new second-
ary seat through the hole of the secondary
lever.
9. Set the secondary spring on its seat on the
back of the Regulator body, then position the
secondary lever and fulcrum pin assembly
on top of the secondary spring. Push down,
compressing the spring until the fulcrum pin
can be slid into place.
10. Insert screw to hold lever and torque to 4.5
Nm (40 in. lbs.) .
11. Verify the secondary lever height by placing
a straight edge over the mating surface (rim)
of the Regular body. The distance between
the rim of the Regulator (as determined by a
straight edge) and lever should be 1/32”
(.794mm). If the measurement does not
meet this specification, the EPR cannot be
repaired and must be replaced.
12. Place the EPR Actuator facing upward and
place the new clamp plate seal into the open
end of the Actuator.
13. Place the Regulator above the Actuator, not-
ing the position of the lever tab and slot on
the secondary diaphragm. Carefully slide
the lever tab into the slot of the secondary
diaphragm and align the Regulator to the Ac-
tuator. Place the Regulator on top the
Actuator, aligning the screw holes.
14. Insert the six screws through the Actuator
holes and into the Regulator. Finger tighten
as many screws as possible.
15. Holding the Regulator to the Actuator, turn
the assembly over so that it is resting on its
face. Torque screws to 40 in. lbs. (4.5
Nm) .
Optional:
If hoses and O-rings were removed during the
Removal Procedure, then follow the additional
steps 17-20; otherwise, continue to Step 21.
16. Lubricate new O-rings using petroleum jelly
or Vaseline. Mount new O-rings on the
Temperature Sensor and hose fittings.
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 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.
17. Mount EPR assembly in vehicle and recon-
nect electrical connector to EPR.
18. Insert Temperature Sensor and hose fittings
into EPR and lock each into place using orig-
inal retaining clips.
19. Remove clamps on coolant hoses. Check
coolant fluid level.
20. Clean Shut-Off Valve fitting, apply LPG com-
patible pipe thread sealer and install into
EPR assembly.
Do not use Teflon tape to seal any LPG fit-
tings.
21. Reconnect negative battery cable.
22. Open valve on the LPG tank.