Dodge ram truck 3500 1996 Service Manual page 1319

B R FUEL SYSTEM 1 4 - 8 5
D I A G N O S I S A N D T E S T I N G ( C o n t i n u e d )
IDLE SPEED ADJUSTMENT
The high idle stop screw is factory sealed and can­
not be adjusted. Low-speed idle can be adjusted.
(1) Use an optical tachometer such as Snap-on No.
MT139 or MTE (Cummins tool division) No. 3377462
to read the engine rpm.
(2) Bring the engine to normal operating tempera­
ture.
(3) Adjust the low idle speed at the low idle speed
screw. The screw and locknut are located at the rear
of the fuel injection pump (Fig. 37).
LEVER STOP
FACTORY
SEAL
HIGH IDLE LOCKNUT
STOP SCREW
LOW IDLE
ADJUSTING
SCREW
J9414-103
Fig. 37 Low idle Speed Screw
(4) Loosen the idle screw lock nut (Fig. 37). Adjust
idle screw to obtain specified rpm (Fig. 38).
(5) Tighten the locknut after adjustment.
LOW I D L E S P E E D
H I G H I D L E S P E E D
With
automatic transmission...
V50-800
RPM with transmission
in
drive
and air conditioning on.
Do not attempt to adjust
high idle speed. High idle
speed
adjustment screw
is factory sealed. Breaking
seal will void injection pump
warranty.
With manual transmission...
V80 RPM with transmission in
neutral and air conditioning on.
Do not attempt to adjust
high idle speed. High idle
speed
adjustment screw
is factory sealed. Breaking
seal will void injection pump
warranty.
* With engine at normal operating temperature. Refer to text
for idle adjustment procedures.
r J9414-66
Fig. 38 Idle Speeds—Diesel Engine
SERVICE PROCEDURES
AIR BLEED PROCEDURE
A certain amount of air becomes trapped in the
fuel system when fuel system components are ser­
viced or replaced. Bleed the system after fuel system
service according to the following procedures.
WARNING: DO NOT BLEED AIR FROM THE FUEL
SYSTEM OF A HOT ENGINE. DO NOT ALLOW FUEL
TO SPRAY ONTO THE EXHAUST MANIFOLD WHEN
BLEEDING AIR FROM THE FUEL SYSTEM.
MANUAL BLEEDING
Some air enters the fuel system when the filters or
injection pump supply line are changed. This small
amount of air is vented automatically from the injec­
tion pump through the fuel drain manifold. This is i f
the filter was changed according to instructions.
The system will have to be bleed manually if:
• The fuel filter is not filled before installation
• The fuel injection pump is replaced
• High-pressure fuel line connections are loosened
or lines replaced
• Initial engine start-up or start-up after an
extended period of no engine operation.
(1) Loosen the low-pressure bleed bolt (Fig. 39).
FUEL
DRAIN
MANIFOLD
BOLT
FUEL FILTER/
WATER SEPARATOR
HOUSING
J9414-86