1953 JEEP DJ ignition

E

FUEL
SYSTEM
E-78. SERVICE DIHGNOSIS
Symptoms Probable Remedy

Excessive
Fuel
Consumption:
Tires
improperly inflated Inflate

Brakes
drag Adjust
Engine
operates too cold Check thermostat
Heat control valve inoperative Check thermostatic spring
Leak
in fuel line Check all connections

Carburetor
float level high. See
"Carburetor"
section
Accelerator pump not properly adjusted Adjust

Leaky
fuel pump diaphragm Replace
Loose
engine
mountings causing high carburetor fuel level Tighten Ignition timing slow or spark advance stuck See "Distributor" section

Low
compression. Check valve tappet clearance
Air
cleaner dirty
.
Remove and clean

Engine
Hesitates on Acceleration: Accelerator pump
does
not function perfectly.
...................
.Replace piston and rod or adjust
Carburetor
float level. ... .Adjust

Spark
plugs Replace or clean and adjust

Low
compression Check valves

Distributor
points—dirty or pitted Replace

Weak
condenser or coil Replace

Carburetor
jets restricted Remove and clean

Excessive
engine
heat See "Engine" section

Engine
Stalls—Won't Idle:
Improper
condition of carburetor See
"Carburetor"
section

Low
speed
jet restricted Remove and clean
Dirty
fuel sediment bowl screen Remove and clean

Air
cleaner dirty Remove and clean

Leaky
manifold or gasket Replace

Fuel
pump diaphragm porous. Replace
Loose carburetor. Tighten
flange
nuts

Water
in fuel
Drain
and clean system

Improper
ignition. .See "Distributor" section

Spark
plugs Clean and adjust

Valves
sticking.
Grind
valves 134

'Jeep'
UNIVERSAL SERIES SERVICE
MANUAL

Fl
EXHHUST
EMISSION
CONTROL
SYSTEM

Contents

HURRICANE
F4-134
ENGINE
SUBJECT
PAR.

GENERAL
Fl-1

AIR
PUMP
Fl-2

PUMP
AIR
FILTER
Fl-3

AIR
DELIVERY
MANIFOLD
Fl-4

AIR INJECTION TUBES.
Fl-5

ANTI-BACKFIRE
DIVERTER
VALVE.
.Fl-6

ENGINE
COMPONENTS
. .Fl-7
Carburetor
. .Fl-8

Distributor
........
.Fl-9
Exhaust
Manifold Fl-10

MAINTENANCE
Fl-11
Carburetor
Fl-12,
Fl-13

Distributor
Fl-14

Anti-Backfire
Diverter
Valve.
.........
.Fl-15

Check
Valve Fl-16

Fl-1. GENERAL—F4-134
Engine

The
Hurricane
F4-134
engine
Exhaust
Emission
Control
System consists of a belt driven air pump

which
directs compressed air through connecting

hoses
to a steel distribution manifold into stainless steel injection
tubes
in the exhaust port adjacent
to each exhaust valve stem.
This
air with its normal

oxygen
content, reacts with the hot but incom­
pletely burned exhaust
gases
and permits further combustion in the exhaust port or manifold.
Fl-2. AIR
PUMP

The
air injection pump is a positive displacement
vane type which is permanently lubricated and
requires
no periodic maintenance.

The
pump contains an integral relief valve which controls the air supplied to the
engine
exhaust ports

during
high speed operation to limit maximum ex­
haust system temperatures.

Fl-3. PUMP
AIR
FILTER

The
air filter attached to the pump is a replaceable
element type constructed of conventional pleated
paper
with steel end plates.

The
filter should be replaced every
12,000
miles
[19,200
km.] under normal conditions or sooner

under
adverse weather or driving conditions.

Fl-4.
AIR
DELIVERY
MANIFOLD

The
air delivery manifold, constructed of cold
rolled
steel with a zinc plating, distributes the air

from
the pump to each of the air delivery
tubes

in
a uniform manner.

A
check valve is attached to the air delivery
SUBJECT
PAR.

Air
Pump Fl-17
Carburetor
Air Cleaner Fl-18

REMOVAL PROCEDURES
.Fl-19
Air
Pump
Fl-20
Anti-Backfire
Diverter Valve Fl-21
Air
Distribution Manifold,
And
Air Injection Tubes
Fl-22

REQUIRED
EQUIPMENT
.Fl-23

REPLACEMENT
PARTS
Fl-24

WARRANTY
Fl-25

DIAGNOSIS
GUIDE
Fl-26
MAINTENANCE CHART
Fl-27

CARBURETOR SPECIFICATIONS
Fl-28

DISTRIBUTOR SPECIFICATIONS
Fl-29
SPARK PLUG
GAP
.Fl-30

manifold.
Its function is to prevent the reverse flow
of exhaust
gases
to the pump should the pump
drive
fail.
This
reverse flow would damage the air
pump and connecting
hose.

Fl-5.
AIR
INJECTION
TUBES

The
air injection
tubes
of stainless steel are inserted
into machined
bosses
of the exhaust manifold. The

tubes
project into the exhaust ports directing air
into the vicinity of the exhaust valve stem.

Fl-6.
ANTI-BACKFIRE DIVERTER VALVE

The
anti-backfire diverter valve prevents
engine
backfire
by briefly interrupting the air being in­
jected into the exhaust manifold during periods of deceleration (rapid throttle closure).

Fl-7.
ENGINE
COMPONENTS

The
following items
vary
in design or specifications

from
those
on vehicles not equipped with the Ex­
haust Emission
Control
System.

Fl-8.
Carburetor

A
carburetor with a specific flow characteristic is used for exhaust emission control.

A
carburetor dashpot is provided to control the throttle closing speed.

Fl-t.
Distributor

The
ignition distributor used with the exhaust emission system requires a different advance curve

from
that used on the F4-134
engine
prior
to the
introduction of exhaust emission systems. 143

Fl
EXHAUST EMISSION CONTROL SYSTEMS

12793

FIG.
Fl-1—HURRICANE
F4-134
ENGINE EXHAUST EMISSION CONTROL SYSTEM
1—
Anti-Backfire
Diverter
Valve

2— Air
Pump

3—
Pump
Air
Filter
Injection
Tube(s)
(Inside
Manifold)

5—Air
Delivery
Manifold
6—
Check
Valve
Ignition
timing must be set at 0 or at top dead
center.

Fl-10.
Exhaust Manifold

The
exhaust manifold is provided with a
boss
that is drilled and tapped at each cylinder to accept the

air
delivery manifold and injection tubes.

Fl-11.
MAINTENANCE

Efficient
performance of the exhaust emission con­
trol
system is dependent upon precise maintenance.
In
addition to the air pump and connecting
hoses

and
tubes, this system's efficiency is dependent
upon special carburetor calibration, distributor cen­

trifugal
advance curve and ignition timing setting

which
must be adjusted at 0 or top dead center.

Road
test
is a factory recommended optional serv­ ice every
6,000
miles
[9,600
km.] to evaluate over­

all
performance.

The
following procedure is recommended to assist
in
diagnosing performance and/or emission level
problems that are peculiar to
Exhaust
Emission

Control
System equipped vehicles.

Fl-12.
Carburetor

Check
carburetor number for proper application. (Specifications are listed at the end of this section)

Check
the dash pot and adjust as required.

Proper
carburetor idle mixture adjustment is im­
perative for
best
exhaust emission control.
The
idle adjustment should be made with the en­
gine
at normal operating temperature and air
cleaner
in place. Adjust the throttle
stop
screw to
idle the
engine
at specified RPM. All lights and accessories must be turned off.

Fl-13.
Carburetor
Idle
Setting
NOTE:
The idle mixture adjustment procedure for
the late model
YF-4941S
and
YF-6115S
Carter
Carburetor
equipped with the
External
Idle
Mix­

ture
Limiter
Cap is the same as outlined below
in
Pars.
"A"
through
"D";
however, because of the

Idle
Limiter
Cap,
the idle mixture screw
CANNOT

be adjusted in the counter-clockwise
(rich)
direc­
tion. The adjustment is made from the
rich
stop
position and the mixture screw is turned in (clock­
wise) approximately %
turn
to "Lean Best
Idle."
Refer
to Section E, Fig. E-6.

The
"Lean
Best
Idle"
method of idle setting is as follows:

a.
Any scheduled service of ignition system should
precede this adjustment. 144

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL

Fl
b. Connect tachometer to
engine.

c.
Warm
up
engine
and stabilize temperatures.

d.
Adjust
engine
idle to
speed
desired, using throt­
tle idle
speed
adjusting screw.

e.
Carburetors without Idle
Limiter
Cap turn idle mixture screws out (counterclockwise) until a
loss

of
engine
speed
is indicated; then, slowly turn mix­
ture screw in (clockwise-leaner) until maximum

speed
(RPM) is reached. Continue turning in (clockwise) until
speed
begins
to drop; turn mixture
adjustment back out (counterclockwise-richer) un­

til
maximum
speed
is just regained at a "lean as
possible" mixture adjustment.

Fl-14.
Distributor

Check
the distributor number for proper appli­
cation.
Check
the distributor cam dwell angle and
point condition and adjust to specifications or re­ place as required. (Specifications listed at the end
of this section)
Check
ignition timing and set at

0°
or
TDC.

Fl-15.
Anti-iackfire
Diverter Valve

The
anti-backfire valve remains closed
except
when
the throttle is closed rapidly from an
open
position.

To
check the valve for proper operation, accelerate
the
engine
in neutral, allowing the throttle to
close

rapidly.
The valve is operating satisfactorily when
no exhaust system backfire occurs. A further check
to determine whether the valve is functioning can be made by removing from the anti-backfire valve
the large
hose
Which
connects to the check valve.
Accelerate the
engine
to allow the throttle to
close

rapidly.
The valve is operating satisfactorily if a
momentary interruption of rushing air is audible.

Fl-16.
Check Valve

The
check valve prevents the reverse flow of ex­
haust
gases
to the pump in the
event
the pump
should, for any reason,
become
inoperative or should exhaust pressure ever
exceed
pump pressure.

To
check this valve for proper operation, remove the air supply
hose
from the pump at the
distri­

bution manifold.
With
the
engine
running, listen for exhaust leakage at the check valve which is
connected to the distribution manifold.

Fl-17.
Air
Pump

Check
for proper drive belt tension with belt tension
gauge
W-283. The belt strand tension should be

50-60
pounds on a belt with previous service, meas­

ured
on the
longest
accessible span
between
two pulleys. When installing a new belt, adjust the
tension to
60-80
pounds tension. DO NOT PRY
ON
THE DIE
CAST
PUMP
HOUSING.

To
check the pump for proper operation, remove the air
outlet
hose
at the pump.
With
the
engine

running,
air discharge should be
felt
at the pump

outlet
opening. The pump
outlet
air pressure, as determined by the relief valve, is preset and is not
adjustable.

The
air pump
rear
cover assembly, housing the pressed in inlet and discharge tubes, and the pres­
sure relief valve are the only pump
components

recommended for service replacement. These parts
are
to be replaced only when damaged as a result
of handling or in the
event
the relief valve was
tampered with.

Fl-18.
Carburetor
Air
Cleaner

Every
6000
miles
[9,600
km.] clean the inside
sur­

face at the sump and
refill
to indicated oil level with
SAE
40 or 50
engine
oil
above
32 F; SAE 20

below
32 F. Wash filter
element
in kerosene and

drain.
Reassemble the air cleaner.

More
frequent cleaning and replacement is advis­ able when the car is operated in dusty areas or on
unpaved roads. Accumulated dirt restricts air flow,
reducing fuel
economy
and performance.

Fl-19.
REMOVAL
PROCEDURES

The
following paragraphs
give
the procedures for removing the major units of the Exhaust Emission

Control
System and the required equipment
needed.

Fl-20.
Air
Pump

Loosen
the air pump adjusting strap to facilitate

drive
belt removal. Remove the air pump air dis­
charge hose(s) and air filter attachment. Separate
the air pump from its mounting bracket. At time of installation, torque tighten the air pump mount­ing
bolts
to
30-40
lbs-ft. [4,15 a 5,53 kg-m.]. Adjust
the belt strand tension to
50-60
pounds on a belt
with previous service and
60-80
pounds on a new
belt.

Fl-21.
Anti-Backfire
Diverter Valve

The
anti-backfire diverter valve removal requires disconnecting the
hoses
and bracket to
engine
at­
taching screws.

Fl-22.
Air
Distribution
Manifold
and
Injection Tubes

In
order to remove the air distribution manifold
without bending the tubing, which could result in
fractures
or leakage, it is necessary to remove the
exhaust manifold as an assembly from the
engine.

After
the exhaust manifold assembly is removed
from
the
engine,
place the manifold in a vise and

loosen
the air distribution manifold
tube
retaining nuts at each cylinder exhaust port. Tap the injec­
tion
tubes
lightly to allow the air distribution mani­
fold to be pulled away partially from the exhaust manifold. The stainless steel injection
tubes
in the
exhaust manifold may have
become
partially fused
to the air distribution manifold and, therefore, may
require
application of heat to the joint in order to
separate. While applying heat to the joint, rotate
the injection
tubes
with pliers being careful not to
damage the
tubes
by applying excessive force.

At
time of installation, the air injection
tubes
must
be positioned into the exhaust manifold prior to
placing the exhaust manifold assembly on the en­ gine.

Note:
Two different length injection
tubes
are used.

The
shorter length injection
tubes
must be inserted into cylinders 1 and 4. 145

Fl

EXHAUST
EMISSION CONTROL SYSTEMS The
air distribution manifold should be installed
after the exhaust manifold assembly is torqued
to the cylinder head. The recommended procedure
for exhaust manifold assembly installation is as follows:
Clean
the mating surface of both the
manifold and cylinder head.
Install
the exhaust manifold to the cylinder head using a new gasket.

Tighten
the manifold to cylinder head, attaching
bolts
down evenly.
Finish
torque tightening to 29
to 35 ft. lbs. [3,4 a 4,8 kg-m.].

Fl-23.
REQUIRED
EQUIPMENT

Each
station licensed to perform repair and main­
tenance on the Exhaust Emission Control System
must be equipped with that equipment necessary
for major
engine
tune-up analysis which shall in­ clude at least the following or equivalent.
Ignition Analyzer Oscilloscope
Ammeter
Ohmmeter
Voltmeter Tachometer
2 Vacuum Gages

Pressure
Gage (0-10 psi.)

Cam
Angle Dwell Meter Ignition Timing
Light

Engine
Exhaust Combustion Analyzer Compression Tester

Fl-24.
REPLACEMENT
PARTS

Parts
necessary to repair and/or maintain the

Exhaust
Emission Control System are available through any Jeep
SALES CORPORATION
ware­
house.

Fl-25.
WARRANTY

All
parts of the Exhaust Emission Control System

are
covered by the Manufacturer's Warranty as stated in the Warranty Service and 'Jeep' Quality
Maintenance Plan booklet.

Fl-26.
EXHAUST EMISSION CONTROL
SYSTEM
DIAGNOSIS GUIDE
Pump Noisy

Hoses Touching Other Parts of Engine or Body (Hood).

Note:
The air pump is not completely noiseless.

Under
normal conditions, pump
noise
rises in pitch as
engine
speed
increases. It is also desirable to
allow for normal break-in wear of the pump prior
to replacement for excessive noise.

Pump Seized

Replace
pump.

Leak
In
Hose

Check
for leaks; using
soap
and water — tighten
clamps or replace
hoses.
Pump
Inoperative

Loose Belt — tighten belt — do not pry on housing.

Filter
Plugged — replace.

Exhaust Backfire

Check
for vacuum leaks — correct as necessary.
Check
air filter for excessive
restriction
— replace as necessary.

Check
anti-backfire valve — replace as necessary.

Induction System Backfire

Verify
engine
timing and distributor dwell.

Verify
accelerator pump charge. 146

Fl

EXHAUST
EMISSION
CONTROL
SYSTEMS
IMPORTANT
NOTICE

The
Exhaust
Emission Systems covered
in
this publication
meet
State and

Federal
requirements for hydrocarbon and carbon
monoxide
emissions.

To
assure continued proper operation,
these
systems
must
be
inspected

regularly,
parts must be replaced
at
factory-recommended intervals and
engine

tune-up services performed at intervals specified in the
Exhaust
Emission
Con­
trol
System Maintenance charts.

For
the
above
reasons,
these
systems
must not, under any circumstances,
be

altered
to anything other than
required
specifications provided in this publication.

Further,
the
Exhaust
Emission
Control
System, or any
of
its components, must
not be physically altered or modified in any respect.

DHTfl
TAG

For
the serviceman's guidance, each vehicle equipped with exhaust emission

control
will
have data
tag
permanently affixed
to the
radiator shroud—-in
example:

VEHICLE
EMISSION
CONTROL
INFORMATION
MODEL
F4-134
C.I.D.

•
ENGINE
AT
NORMAL
OPERATING
TEMPERATURE

•
LIGHTS
AND
ALL
ACCESSORIES OFF

•
IDLE
MIXTURE
. . .
LEAN
BEST
IDLE

•
IGNITION
TIMING
0*
(TDC)
•
SPARK
PLUG
GAP
. . . .030

•
DWELL
...
42* (.020
POINT
GAP)
•
IDLE
SPEED
. . .
700-750 RPM
TRANSMISSION
IN
NEUTRAL
DURING
TUNE
UP

SEE SERVICE MANUAL
FOR
ADDITIONAL INFORMATION
THIS VEHICLE CONFORMS
TO U.S.
DEPT.
OF
H.E.W.
REGULATIONS APPLICABLE
TO
1971 MODEL YEAR NEW MOTOR VEHICLES

Jeep
CORPORATION
14401

Important:
Always refer
to
the data tag when checking or re-adjusting ignition

timing,
idle speed, and idle mixture. 148

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

F2

FIG.
F2-2—DAUNTLESS
V-6
ENGINE
EXHAUST
EMISSION
HEATED
AIR
SYSTEM
1—
Air
Cleaner 4—Adapter
Elbow
and Hose
2—
Vacuum
Motor 5—Manifold Heat Collector
3—
Control
Damper and
Linkage
accelerating the
engine
hard
will
cause the vacuum
level in the intake manifold and in the vacuum motor to drop. Whenever vacuum drops
below
5 inches [12,7 cm.] the diaphragm spring
will
open

the cold air door wide in order to get the maximum

air
flow required for maximum acceleration.
F2-3.
MAINTENANCE

Efficient
performance of the
Exhaust
Emission
System is
dependent
on precise maintenance. In
addition to the heated air system, air pump, con­ necting
hoses
and tubes, it is essential that the

carburetor
and ignition distributor be properly ad­
justed to specifications listed at the end of this section.

Road
test
is a factory-recommended optional serv­
ice every
6,000
miles
[9,600
km.] to evaluate
overall
performance.

The
following procedure is recommended to assist

in
diagnosing performance and/or emission level problems that are peculiar to Controlled Combus­
tion Equipped vehicles.

F2-4.
Testing Thermo
Air
Cleaner Operation
Since
failure of the air cleaner
will
generally result

in
the snorkel cold air door staying open, failure
will
probably go unnoticed in warm or hot weather.
In
cold weather, however, owners
will
complain of
leanness, hesitation, sag, surge or stalling. When any
type
of lean operation complaint is received, always

test
the heated air system for proper functioning
before
doing any work on the carburetor.

Note:
Always perform checks in the same order
as listed
below.
151

F2
EXHAUST EMISSION CONTROL SYSTEMS
the throttle
stop
screw to idle the
engine
at 650
to 700 rpm.

F2-17. Carburetor Idle Setting
The
"Lean
Best
Idle"
Method of Idle Setting is as
follows:

a.
Any scheduled service of ignition system should
precede this adjustment

b.
Connect tachometer to engine.

c.
Warm
up
engine
and stabilize temperatures.

d.
Adjust
engine
idle to speed desired, using throt­
tle idle speed adjusting screw.
e.
Turn
idle mixture screws out (counterclockwise)

until
a
loss
of
engine
speed is indicated; then slowly
turn
mixture screws in (clockwise-leaner)
until
maximum speed (rpm) is reached. Continue

turning
in (clockwise) until speed begins to drop;

turn
mixture adjustment back out (counterclock­
wise-richer)
until maximum speed is just regained

at
a "lean as possible" mixture adjustment.

F2-18. Distributor
The
ignition distributor used with the
Exhaust
Emission
Control
System is the same as that used
on
engines
without
Exhaust
Emission
Control.
Check
the distributor cam dwell angle and point
condition.
Check
ignition timing and adjust to specifications shown on the last
page
of this section.

F2-19.
Anti-Backfire
Valve

The
anti-backfire valve remains closed except when
the throttle is closed rapidly from an open position.
To
check the valve for proper operation, accelerate
the
engine
in neutral, allowing the throttle to close

rapidly.
The valve is operating satisfactorily when
no exhaust system backfire occurs. A further check
to determine whether the valve is functioning can
be made by removing from the anti-backfire valve
the large
hose
which connects the valve to the

pump.
With
a finger placed over the open end of
the
hose
(not the valve), accelerate the
engine
and allow the throttle to close rapidly. The valve is
operating satisfactorily if a momentary air rushing
noise is audible.

F2-20.
Check
Valve

The
check valves in the lines to the air distribution manifolds prevent the reverse flow of exhaust
gases

to the pump in the event the pump should, for

any
reason,
become
inoperative or should exhaust

pressure
ever exceed pump pressure.

To
check this valve for proper operation, remove the air supply
hose
from the pump at the check

valve.
With
the
engine
running, listen for exhaust
leakage at the check valve which is connected to
the distribution manifold.

F2-21.
Air
Pump

Check
for proper drive belt tension with belt tension
gauge
W-283. The belt strand tension should be 60 pounds measured on the
longest
accessible span
between two pulleys. DO NOT PRY ON THE

DIE
CAST
PUMP
HOUSING. To
check the pump for proper operation, remove
the air
outlet
hose
at the pump.
With
the
engine

running,
air discharge should be felt at one of
the pump
outlet
openings. The pump
outlet
air
pressure,
as determined by the relief valve, is preset
and
is not adjustable.

The
air pump
rear
cover assembly, housing the pressed in inlet and discharge tubes, and the pres­
sure
relief valve are the only pump components
recommended for service replacement. These parts
are
to be replaced only when damaged as a result
of handling or in the event the relief valve was
tampered with.

F2-22.
Intake Manifold

Intake
manifold leaks must not be overlooked. Air
leakage at the intake manifold may be compen­
sated for by
richer
idle mixture setting, however, this
will
usually cause uneven fuel-air distribution
and
will
always result in
loss
of performance and
exhaust emission control. To check for air leakage
into the intake manifold, apply kerosene or naph­
tha,
on the intake manifold to cylinder head joints

and
observe whether any changes in
engine
rpm

occur.
If an air leak is indicated, check the mani­
fold to cylinder head bolt torque. The correct torque is 25-35 lbs. ft. [3,46 a 4,84 kg-m.]. If the

leak
is
still
evident,
loosen
the manifold assembly

and
torque-tighten the bolts evenly.
Start
from the center and use proper torque values. Replace the
manifold
gasket if the leak
still
exists.
Clean
both
mating surfaces and check for
burrs
or other ir­

regularities.

Always
torque the bolts evenly to the specified
torque value to prevent warpage.

F2-23.
Carburetor
Air
Cleaner
—Oil
Bath

Every
6,000
miles [9,600 km.] disconnect attach­

ing
hoses
and unscrew the wing nut from the top
of the air cleaner and lift it off the carburetor.

Lift
the cover and filter element off the oil sump.

Clean
the inside surface of the sump and
refill
to

indicated
oil level with SAE 40 or 50
engine
oil
above 32 F; SAE 20 below 32 F.
Wash
filter element in kerosene and
drain.
Reassemble the air

cleaner
and install on carburetor.

More
frequent cleaning and replacement are advis­ able when the car is operated in dusty areas or on

unpaved
roads. Accumulated
dirt
restricts air flow,
reducing
fuel economy and performance.

F2-24.
REMOVAL PROCEDURES
The
following paragraphs
give
the procedures for removing the major units of the exhaust emission
control
system and the required equipment needed.

F2-2S.
Air
Pump

Loosen
the air pump mounting bracket bolts. Re­ move the air pump air hose(s). Separate the air pump from its mounting bracket. At time of install­
ation,
torque tighten the air pump mounting bolts
to
30-40
lbs.-ft [4,15 a 5,53 kg-m.].
Adjust
the
belt strand tension to 60 pounds. 156