Positive Crankcase Ventilation (Pcv) System; Restrictor Plates; Non-Integral Exhaust Back-Pressure Sensor Test - Jeep 1979 CJ-5 Technical & Service Manual

Remvil
(1) Remove vacuum lines from exhaust back-pres-
sure sensor valve and EGR valve.
(2) Remove two attaching nuts from EGR valve.
(3) Remove EGR valve and exhaust back-pressure
sensor assembly.
(4) Clean intake manifold and back-pressure sensor
ports and all mating surfaces.
Installation
(1) Install replacement gasket on intake manifold
and position exhaust back-pressure sensor on top of
gasket.
NOTE: Exhaust back-pressure sensor assembly should
extend toward the left side on eight-cylinder engines.
(2) Install replacement gasket on exhaust back-
pressure sensor spacer and install EGR valve.
(3) Install support bracket to valve portion of sen-
sor and tighten screws.
(4) Install two attaching nuts and tighten to 13 foot-
pounds (18 N®m) torque.
(5) Attach vacuum lines to exhaust back-pressure
sensor valve and EGR valve.
NOTE: Vacuum line from CTO switch must be con-
nected to nipple with 0.030-inch (0.762 mm) restriction.
Non-Integral Exhaust Back-Pressure Sensor Test
(1) Inspect all EGR vacuum lines for leaks and cor-
rect routing.
(2) Install tee in vacuum line between EGR valve
and exhaust back-pressure sensor.
(3) Attach vacuum gauge to tee.
(4) Start engine and allow to idle. No vacuum
should be indicated.
NOTE: If vacuum is indicated at idle speed, verify cor-
rect line connections. Be sure manifold vacuum is not
being used as source. If carburetor is providing ported
vacuum, inspect for partially-open throttle plate, which
could apply premature ported vacuum to back-pressure
sensor.
(5) Accelerate engine to 2000 rpm and observe vac-
uum gauge for the following:
•If coolant temperature is below 115°F (46°C), no
vacuum should be indicated.
• If coolant temperature is above 115°F (46°C) (black
CTO switch) or 160°P(71°G) (yellow CTO switch),
ported vacuum should be indicated.
• I f no vacuum was indicated during test, be sure
vacuum is being applied to inlet side of back-pres-
sure sensor. Then remove back-pressure sensor and
inspect spacer port and tube for restrictions. Re-
strictions caused by carbon or lead deposits can be
removed with spiral wire brush. Otherwise, replace
back-pressure sensor.
RESTRICTOR PLATES
NOTE: Restrietor plates are used only on vehicles
equipped with the non-integral back-pressure sensor.
The restrietor plate (fig. 1J-75) is located between the
exhaust back-pressure sensor spacer and the intake
manifold, mounted between gaskets. The stainless steel
restrietor plate is calibrated for a particular engine/
exhaust system and should never be altered or replaced
with a restrietor plate of different calibration.
A J 4 3 0 4 4
Fig. 1J-75 Reslricfor Piafe
P O S I T I V E C R A N K C A S E
V E N T I L A T I O N ( P C V )
S Y S T E M
Page Pige
Components 1J-42 Operation PCV Air Ifriet Filter 1J-42
General 1J-41 PCV Valve Test 1J-42
crankcase and vapors are drawn out, channeled into the
The PCV system prevents crankcase vapors from en- intake manifold and burned in the combustion
tering the atmosphere. Filtered air is directed into the chambers.