Jeep J-10 Series 1982 Technical & Service Manual page 462

1K-10 EXHAUST SYSTEMS
AIR
OUTLET
INTERNAL
SILENCER
DIAPHRAGM
SPRING
VACUUM
AIR
INLET
(FROM
AIR
PUMP)
DIVERT AND
PRESSURE
RELIEF OUTLET
(METERING
VALVE IN
BYPASS
POSITION) AS0277
Fig. 1K-12 Diverter Valve—Typical
FunctionalTest
WARNING: Use extreme caution when engine is oper
ating. Do not stand in direct line with fan. Do not put
hands near pulleys, belts or fan. Do not wear loose
clothing.
(1) Start engine and operate at idle.
(2) Examine diverter valve vent. Little or no air
should flow from vent.
(3) Accelerate engine to 2000-3000 rpm and rapidly
close throttle. A strong flow of air should pass from
diverter valve vent for approximately three seconds. If
air does not flow or if engine backfire occurs, ensure
vacuum hose has vacuum and there is no air leak.
NOTE: The diverter valve diverts and vents air pump
output when a manifold vacuum of20 in. Hg (68 kPa) or
more is applied to the diaphragm. The diverter valve
also operates when pump output exceeds 5 psi (35 kPa).
Some applications require 8 psi (55 kPa).
(4) Slowly accelerate engine. Between 2500 and 3500
rpm air should begin to flow from diverter valve vent.
Replacement
The diverter valve is not serviceable and must be
replaced if defective. The valve is either attached to a
bracket or suspended by the hoses between the air pump
and air injection manifold(s). Removal involves dis
connecting the air hoses, vacuum hose and bracket
clamp, if used. Installation entails connecting the air
hoses, vacuum hose and bracket clamp, if used.
Air Injection Manifolds
Air injection manifolds are constructed of cold-rolled
steel with zinc plating. They distribute air via the di
verter valve from the air pump to each of the exhaust
manifold inlet ports.
A check valve, incorporating a stainless steel spring
plunger and an asbestos seat, is integral with the air
injection manifold. Its function is to prevent the reverse
flow of exhaust gas to the pump during pump or belt
failure, or diverter valve bypass operation. Reverse ex
haust gas flow would damage the air pump and con
necting hoses.
The distribution tubes of the air injection manifold
are connected directly to the exhaust manifold. The hol
low attaching fittings route airflow into the exhaust
manifold inlet ports.
Check Valve Functional Test
To test the air injection manifold check valve for
proper operation, disconnect the air supply hose at the
injection manifold. With the engine operating above idle
speed, listen and feel for exhaust leakage from the check
valve. A slight leak is normal.
Removal—Six-Cylinder Engine
(1) Disconnect air delivery hose at check valve.
(2) Remove distribution tube fittings from exhaust
manifold inlet ports.
NOTE: Some resistance to turning may be encountered
because of carbon build-up on the threads.
(3) Remove air injection manifold.
Installation—Six-Cylinder Engine
(1) Connect air injection manifold with fittings to
exhaust manifold. Tighten fittings with 20 foot-pounds
(27 N»m) torque.
(2) Connect air delivery hose.
Removal—Eight-Cylinder Engine
(1) Disconnect air delivery hose at check valve.
(2) Remove distribution tube fittings from exhaust
manifold inlet ports.
NOTE: Some resistance to turning may be encountered
because ofcarbon build-up on the threads.
(3) Remove air injection manifold.
(4) Remove sealing gaskets from air injection
manifold.