Jeep J-10 Series 1982 Technical & Service Manual page 464

1K-12 EXHAUST SYSTEMS
DUAL AIR INJECTION SYSTEM DIAGNOSIS
General
The dual air injection system should be diagnosed in
conjunction with the CEC System. Refer to Chapter
U—Fuel Systems.
DiverterValve
Test the diverter valve as outlined in Single Air In
jection System Components.
NOTE: // the engine is at normal operating temper
ature, manifold vacuum will have to be temporarily
connected to the valve during the test because the con
trol valve circuit will be in operation.
Air Bypass Circuit
Functional Test
(1) Disconnect air hoses from ports A and B of air
control valve. Hose A is connected to air injection mani
fold. Hose B is connected to catalytic converter.
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.
(2) Start engine and warm to normal operating
temperature. Turn ignition off.
(3) Restart engine and increase speed to 1500 rpm.
Air should exhaust from port A of air control valve for
approximately 30 seconds, then exhaust from port B.
(a) If no air exhausts, inspect diverter valve
vents for air exhaust.
1. If air is being exhausted, increase engine
speed to 1500 rpm and determine if vacuum is being
applied to diverter valve.
2. If vacuum is present, replace diverter
valve and retest. If no vacuum is present, refer to Chap
ter U—Fuel Systems and test divert solenoid.
3. If air is not being exhausted, inspect air
pump for proper operation.
(b) If air exhaust from air control valve is nor
mal, depress accelerator pedal to floor, return engine to
idle and inspect diverter valve vents for air exhaust.
1. If air is exhausted, circuit is operating
normally.
2. If air is not exhausted, check diverter
valve vacuum hose for vacuum. If no vacuum, replace
diverter valve. If vacuum is present, refer to Chapter
U—Fuel Systems and test divert solenoid.
Air Control Circuit
NOTE: Engine must be at normal operating
temperature.
Functional Test
(1) Disconnect air hoses from ports A and B of air
control valve. Hose A is connected to air injection mani
fold. Hose B is connected to catalytic converter.
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.
(2) Start engine and warm to normal operating
temperature . Turn ignition off.
(3) Restart engine and increase speed to 1500 rpm.
Air should exhaust from port A of air control valve for
approximately 30 seconds, then exhaust from port B.
(a) If no air exhausts, inspect diverter valve
vents for air exhaust.
1. If air is exhausted, with engine at 1500
rpm, determine if vacuum is being applied to diverter
valve.
2. If vacuum is present, replace diverter
valve and retest.
3. If vacuum is not present, refer to Chap
ter U—Fuel Systems and test divert solenoid.
4. If air is not exhausted, inspect air pump
for proper operation.
(b) If air exhausts from both ports, replace air
control valve and retest system.
(c) If air exhausts only from port B, remove
vacuum hose and check for vacuum during first 30 sec
onds of operation.
1. If vacuum is not present, replace air con
trol valve and retest.
2. If vacuum is present, refer to Chapter
U—Fuel Systems and test upstream solenoid.
(d) If air exhaust is normal, depress accelerator
pedal to floor, return engine to idle and inspect diverter
valve vents for air exhaust.
1. If air is exhausted, system is operating
normally.
2. If air is not exhausted, check diverter
valve vacuum hose for vacuum. If no vacuum, replace
diverter valve. If vacuum is present, refer to Chapter
U—Fuel Systems and test divert solenoid.
COOLANT TEMPERATURE SWITCH REPLACEMENT
WARNING: Serious burns can result if hot coolant is
not drained before removing the switch from the intake
manifold.
(1) Drain coolant from radiator.
(2) Disconnect wire connector.