Jeep J-10 Series 1982 Technical & Service Manual page 461

Service Precautions
The following list of service precautions are for pre
venting damage to the air pump.
• Do not attempt to prevent the pulley from rotating
by inserting tools into the centrifugal filter fan.
•Do not operate an engine with the pump belt re
moved or disconnected except for noise diagnosis.
• Do not attempt to lubricate any part of the pump.
• Do not clean the centrifugal filter.
•Do not disassemble the pump or remove the rear
cover.
• Do not exceed 20 foot-pounds (27 N»m) torque when
tightening the mounting bolts.
• Do not pry on the aluminum housing to adjust the
, belt tension.
• Do not clamp the pump in a vise.
• Do not permit liquids to enter the pump when steam
or water pressure-cleaning the engine.
Removal—Six-Cylinder Engine with V-Belts
(1) Disconnect air pump output hose at back of air
pump.
(2) Remove adjustment bolt and remove drive belt.
(3) Remove front mounting bracket.
(4) Remove adjustment bracket from cylinder head.
(5) Slide pump from pivot stud.
Installation—Six-Cylinder Engine with V-Belts
(1) Slide pump onto pivot stud.
(2) Install front mounting bracket.
(3) Install adjustment bracket and install adjust
ment screw.
CAUTION: Adjust the belt tension by hand only.
(4) Install drive belt and adjust to specified tension.
Tighten pivot stud nut.
(5) Connect air pump output hose to back of pump.
Removal—Six-Cylinder Engine with Serpentine Belt
• (1) Release belt tension by loosening alternator ad
justment and pivot bolts.
(2) Disconnect air pump output hose from back of
pump.
(3) Remove air pump mounting bolts/nuts and air
pump.
installation—Six-Cylinder Engine with Serpentine Beit
(1) Position air pump and secure with mounting
bolts/nuts.
(2) Connect output hose to back of pump.
(3) Tighten belt to specified tension. Refer to Chap
ter 1C—Cooling Systems for tension specification.
EXHAUST SYSTEMS 1K-9
Removal—Eight-Cylinder Engine
(1) Disconnect air pump output hose at pump.
(2) Loosen mount bracket-to-pump attaching screw
and bolt. Remove drive belt.
(3) Remove pivot screw and brace screws.
(4) Remove pump.
Installation—Eight-Cylinder Engine
(1) Position pump at mounting location and install
pivot and brace attaching screws. Do not tighten.
CAUTION: Adjust the belt tension by hand only.
(2) Install drive belt and adjust to specified tension.
(3) Tighten mounting screws and adjusting strap
screw with 20 foot-pounds (27 N»m) torque.
Diverter (Bypass) Valve
A diverter valve is used with all air injection appli
cations. The valves for six- and eight-cylinder engines
differ only in the number of outlets. The six-cylinder
engine diverter valve has one outlet. The eight-cylinder
engine diverter valve has two outlets. A high flow di
verter valve is used on some applications where greater
airflow is required for emission control.
The valve momentarily diverts air pump output from
the exhaust manifold(s) and vents it to the atmosphere
during rapid deceleration. The valve also functions as a
pressure release valve for excessive air pump output. An
internal silencer is also incorporated in the diverter
valve housing to muffle the airflow.
Operation
In a rapid deceleration situation, high intake manifold
vacuum is applied to the diaphragm in the diverter
valve. When the vacuum is 20 in. Hg (68 kPa) or more,
the spring tension of the diaphragm is overcome. This
moves the metering valve down against its upper seat
and away from its lower seat. This diverts and vents air
pump output pressure to the atmosphere (fig. 1K-12).
Air pump output is diverted only momentarily because
of a vent hole in the diaphragm. This hole allows atmos
pheric pressure to quickly equalize on both sides of the
diaphragm and the diaphragm spring returns the meter
ing valve to its normal position.
If the air pump develops excessive output pressure,
the excessive pressure overcomes the diaphragm spring
tension and pushes the metering valve down. Pump out
put pressure is diverted and vented to the atmosphere.
When pump output pressure returns to normal, the me
tering valve moves up from the upper seat and against
the lower seat, returning to its normally open position.
Pump output pressure is then directed to the exhaust
manifold(s).