check engine DODGE RAM 2001 Service Repair Manual

(3) Installrearinjection line bundle beginning
with cylinder head (fuel injector) connections, fol-
lowed by injection pump connections. Tighten all fit-
tings finger tight.
(4) Tighten fittings at fuel injector ends for cylin-
ders number 6 and 5 to 38 N´m (28 ft. lbs.) torque.
Do not tighten number 3 line at this time. It
will be tightened during bleeding procedure.
(5) Tighten 3 fittings at fuel injection pump ends
to 24 N´m (18 ft. lbs.) torque.
(6) Installfrontinjection line bundle beginning
with cylinder head (fuel injector) connections, fol-
lowed by injection pump connections. Tighten all fit-
tings finger tight.
(7) Tighten fitting at fuel injector end for cylinder
number 2 to 38 N´m (28 ft. lbs.) torque.Do not
tighten lines number 1 or 4 at this time. They
will be tightened during bleeding procedure.
(8) Tighten remaining 3 fittings at fuel injection
pump ends to 24 N´m (18 ft. lbs.) torque.
(9) Install fuel line support bracket bolts to intake
manifold and tighten to 24 N´m (18 ft. lbs.) torque.
CAUTION: Be sure fuel lines are not contacting
each other or any other component. Noise will
result.
(10) Install engine lifting bracket at rear of intake
manifold. Tighten 2 bolts to 77 N´m (57 ft. lbs.)
torque.
(11) Install cable bracket housing/cable assembly
and tighten 3 mounting bolts to 24 N´m (18 ft. lbs.)
torque.
(12) Clean any old gasket material below and
above intake manifold air heater element block. Also
clean mating areas at intake manifold and air intake
housing.
(13) Using new gaskets, position intake manifold
air heater element block to engine.
(14) Install air intake housing and position ground
cable. Install 4 mounting bolts and tighten to 24 N´m
(18 ft. lbs.) torque.
(15) Install air tube (intake manifold-to-charge air
cooler) (Fig. 41). Tighten clamps to 8 N´m (72 in. lbs.)
torque.
(16) Install engine oil dipstick tube support mount-
ing bolt and tighten to 24 N´m (18 ft. lbs.) torque.
(17) Install engine oil dipstick to engine.
(18) Connect 2 electrical cables to cable mounting
studs.
(19) Connect electrical connector to bottom of
APPS by pushing connector upward until it snaps
into position.
(20) Connect wiring harness (clip) at bottom of
Accelerator Pedal Position Sensor (APPS) mounting
bracket (Fig. 40).(21) Connect front wiring clip (Fig. 41) to cable
bracket housing.
(22) Install cable cover (Fig. 39).
(23) Connect both negative battery cables to both
batteries.
(24) Bleed air from fuel system. Do this at fuel
injector ends of lines. Use cylinders numbers 1, 3 and
4 for bleeding . (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY - STANDARD PROCEDURE). After
bleeding, tighten fittings to 38 N´m (28 ft. lbs.)
torque.
(25) Check lines/fittings for leaks.
FUEL TANK
DESCRIPTION - DIESEL FUEL TANK
The fuel tank is similar to the tank used with gas-
oline powered models. The tank is equipped with a
separate fuel return line and a different fuel tank
module for diesel powered models. A fuel tank
mounted, electric fuel pump is not used with diesel
powered models. Refer to Fuel Tank Module for addi-
tional information.
For removal and installation procedures, refer to
Fuel Tank - Gasoline Engines.
FUEL TANK MODULE
DESCRIPTION
An electric fuel pump isnot usedin the fuel tank
module for diesel powered engines. Fuel is supplied
by the engine mounted fuel transfer pump and the
fuel injection pump.
The fuel tank module is installed in the top of the
fuel tank (Fig. 48). The fuel tank module (Fig. 48)
contains the following components:
²Fuel reservoir
²A separate in-tank fuel filter
²Rollover valve
²Fuel gauge sending unit (fuel level sensor)
²Fuel supply line connection
²Fuel return line connection
²Auxiliary non-pressurized fuel supply fitting
OPERATION
Refer to Fuel Gauge Sending Unit.
REMOVAL
(1) Drain and remove fuel tank. Refer to Fuel
Tank Removal/Installation.
(2) Thoroughly clean area around tank module at
top of tank.
14 - 78 FUEL DELIVERY - DIESELBR/BE
FUEL LINES (Continued)

(3) The plastic fuel tank module locknut is
threaded onto fuel tank (Fig. 39). Install Special Tool
6856 to locknut and remove locknut (Fig. 49). The
fuel tank module will spring up when locknut is
removed.
(4) Remove module from fuel tank.
INSTALLATION
CAUTION: Whenever the fuel tank module is ser-
viced, the rubber gasket must be replaced.
(1) Thoroughly clean locknut and locknut threads
at top of tank.
(2) Using new gasket, carefully position fuel tank
module into opening in fuel tank.
(3) Position locknut over top of fuel tank module.
Install locknut finger tight.
(4) When looking down at tank from drivers side of
tank, the arrow at top of module should be aligned
between two marks stamped into tank (approximate-
ly 2 o'clock position). The fuel line connectors, roll
over valve and fuel gauge electrical connector should
all be pointed to drivers side of vehicle. Rotate and
align module/tank marks if necessary before tighten-
ing locknut.This step must be performed to pre-
vent the module's float from contacting side of
fuel tank.
(5) Tighten locknut to 24±44 N´m (18±32 ft. lbs.)
torque.
(6) Install fuel tank. Refer to Fuel Tank Removal/
Installation.
FUEL TRANSFER PUMP
DESCRIPTION
The fuel transfer pump (fuel lift pump) is located
on the left-rear side of the engine cylinder block
above the starter motor (Fig. 50). The 12±volt electric
vane-type pump is operated and controlled by the
Engine Control Module (ECM) (Fig. 51).
OPERATION
The purpose of the fuel transfer pump is to supply
(transfer) a low-pressure fuel source:fromthe fuel
tank,throughthe fuel filter/water separator andto
the fuel injection pump. Here, the low-pressure is
raised to a high-pressure by the fuel injection pump
for operation of the high-pressure fuel injectors.
Check valves within the pump, control direction of
fuel flow and prevent fuel bleed-back during engine
shut down.
Normal current flow to the pump is 12 amperes.
With the engine running, the pump has2modes of
operation: Mode 1: 100 percent duty-cycle with a
minimum pressure of 10 psiexcept when the
engine is cranking.Mode 2: 25 percent duty-cycle
with minimum pressure of 7 psiwith the engine
cranking
The 25 percent duty-cycle is used to limit injection
pump inlet pressure until the engine is running.
Fig. 48 Top View of Fuel Tank ModuleÐDiesel
1 - AUXILIARY CAPPED FITTING
2 - FUEL PUMP MODULE
3 - FUEL SUPPLY/RETURN FITTINGS
4 - ELECTRICAL CONNECTOR
5 - LOCKNUT
6 - ROLLOVER VALVE
Fig. 49 Locknut Removal/InstallationÐTYPICAL
MODULE
1 - SPECIAL TOOL 6856
2 - LOCKNUT
BR/BEFUEL DELIVERY - DIESEL 14 - 79
FUEL TANK MODULE (Continued)

(5) Using key, crank engine over while observing
gauge. Pressure should be 5±7 psi.
(6) Re-install fuel system relay to PDC.
(7) Start engine and record fuel pressure. Pressure
should be aminimumof 69 kPa (10 psi) at idle
speed.
(8) Because fuel pump relay was removed, a Diag-
nostic Trouble Code (DTC) may have been set. After
testing is completed, and relay has been installed,
use DRB scan tool to remove DTC.
Pressure Drop Test:
(9) Shut engine off and remove test gauge from
inlet port test fitting. Re-attach 6828 test gauge to
outlet port (Fig. 55). Start engine and record fuel
pressure. Pressure should not be more than 34 kPa
(5 psi) lower than inlet port pressure test. If so,
replace fuel filter.
Fuel Supply Restriction Test:
Due to very small vacuum specifications, the DRB
scan tool along with the Periphal Expansion Port
(PEP) Module and 0±15 psi transducer must be used.
(10) Verify transfer pump pressure is OK before
performing restriction test.
(11) Locate and disconnect fuel supply line quick-
connect fitting at left-rear of engine (Fig. 56). After
disconnecting line, plastic clip will remain attached
to metal fuel line at engine. Carefully remove clip
from metal line. Snap same clip into fuel supply
hose.
(12) Install Special Rubber Adapter Hose Tool
6631 (3/8º) into ends of disconnected fuel supply line.(13) Install transducer from PEP module to brass
ªTº fitting on tool 6631.
(14) Hook up DRB scan tool to transducer.
WARNING: DO NOT STAND IN LINE WITH THE
COOLING FAN FOR THE FOLLOWING STEPS.
(15) Start engine and record vacuum reading with
engine speed at high-idle (high-idle means engine
speed is at 100 percent throttle and no load). The
fuel restriction testMUSTbe done with engine speed
at high-idle.
(16) If vacuum reading islessthan 6 in/hg. (0±152
mm hg.), test is OK. If vacuum reading ishigher
than 6 in/hg. (152 mm hg.), restriction exists in fuel
supply line or in fuel tank module. Check fuel supply
line for damage, dents or kinking. If OK, remove
module and check module and lines for blockage.
Also check fuel pump inlet filter at bottom of module
for obstructions.
Testing For Air Leaks in Fuel Supply Side:
(17) A 3±foot section of 3/8º I.D. clear tubing is
required for this test.
(18) Using a tire core valve removal tool, carefully
remove core valve from inlet fitting test port.
(19) Attach and clamp the 3/8ºclear hose to fitting
nipple.
(20) Place other end of hose into a large clear con-
tainer. Allow hose to loop as high as possibleabove
test port.
(21) The fuel transfer pump can be put into a 25
second run (test) mode if key is quickly turned to
crank position and released back to run position
without starting engine.
To prevent engine from starting in this test, first
remove fuel system relay (fuel injection pump relay).
Relay is located in Power Distribution Center (PDC).
Refer to label under PDC cover for relay location.
Because fuel pump relay was removed, a Diagnos-
tic Trouble Code (DTC) may have been set. After test-
ing is completed, and relay has been installed, use
DRB scan tool to remove DTC.
(22) Allow air to purge from empty hose before
examining for air bubbles. Air bubbles should not be
present.
(23) If bubbles are present, check for leaks in sup-
ply line to fuel tank.
(24) If supply line is not leaking, remove fuel tank
module and remove filter at bottom of module (filter
snaps to module). Check for leaks between supply
nipple at top of module, and filter opening at bottom
of module. Replace module if necessary.
(25) After performing test, install core back into
test fitting. Before installing protective cap, be sure
fitting is not leaking.
Fig. 56 Fuel Return and Supply Line Quick-Connect
Locations
1 - FUEL RETURN LINE
2 - QUICK-CONNECT FITTINGS
3 - FUEL SUPPLY LINE
14 - 82 FUEL DELIVERY - DIESELBR/BE
FUEL TRANSFER PUMP (Continued)

REMOVAL
The fuel transfer pump (fuel lift pump) is located
on left side of engine, below and rearward of fuel fil-
ter (Fig. 57).
(1) Disconnect both negative battery cables at both
batteries.
(2) Thoroughly clean area around transfer pump
and fuel lines of any contamination.
(3) Remove starter motor. Refer to Starter Remov-
al/Installation in 8, Starting System for procedures.
(4) Place a drain pan below the pump.
(5) Disconnect fuel line quick-connect fitting at
fuel supply line (Fig. 57) at rear of pump.
(6) Remove support bracket bolt at top of pump
(Fig. 57).
(7) Remove front and rear banjo bolts at pump
(Fig. 57).
(8) Disconnect electrical connector at side of pump
(Fig. 57).
(9) Remove three pump bracket nuts (Fig. 57) and
remove pump from vehicle.
INSTALLATION
The fuel transfer pump (fuel lift pump) is located
on left side of engine, below and rearward of fuel fil-
ter (Fig. 57).
(1) Install new gaskets to fuel supply line/support
bracket and banjo bolt at rear of pump. Install line
and banjo bolt to pump.Do nottighten banjo bolt at
this time.
(2) Install new gaskets to fuel line and banjo bolt
at front of pump.
(3) Position 3 pump studs into pump mounting
bracket and install 3 nuts.Do nottighten nuts at
this time.
(4) Install support bracket bolt (Fig. 57).Do not
tighten bolt at this time.
(5) Tighten 3 pump nuts to 12 N´m (9 ft. lbs.)
torque.
(6) Tighten both banjo bolts to 24 N´m (18 ft. lbs.)
torque.
(7) Tighten support bracket bolt 12 N´m (9 ft. lbs.)
torque.
(8) Connect electrical connector to pump (Fig. 57).
(9) Connect fuel line quick-connect fitting to fuel
supply line at rear of pump.
(10) Install starter motor. Refer to Starter Remov-
al/Installation in 8, Starting for procedures.
(11) Connect both negative battery cables at both
batteries.
(12) Bleed air at fuel supply line at side of fuel
injection pump. Refer to the Air Bleed Procedure.
(13) Start engine and check for leaks.
OVERFLOW VALVE
DESCRIPTION
The overflow valve is located on the side of the
injection pump (Fig. 58). It is also used to connect
the fuel return line (banjo fitting) to the fuel injection
pump.
OPERATION
Fuel volume from the fuel transfer (lift) pump will
always provide more fuel than the fuel injection
pump requires. The overflow valve (a check valve) is
used to route excess fuel through the fuel return line
and back to the fuel tank. Approximately 70% of sup-
plied fuel is returned to the fuel tank. The valve
opens at approximately 97 kPa (14 psi). If the check
valve within the assembly is sticking open, fuel
drainage of the injection pump could cause hard
starting.
Fig. 57 Fuel Transfer Pump Location
1 - OIL PRESSURE SENSOR
2 - PUMP BRACKET NUTS (3)
3 - SUPPORT BRACKET BOLT
4 - BANJO BOLT (REAR)
5 - FUEL SUPPLY LINE
6 - ELECTRICAL CONNECTOR
7 - BANJO BOLT (FRONT)
8 - FUEL TRANSFER PUMP
BR/BEFUEL DELIVERY - DIESEL 14 - 83
FUEL TRANSFER PUMP (Continued)

If a Diagnostic Trouble Code (DTC) has been stored
for ªdecreased engine performance due to high injec-
tion pump fuel temperatureº, the overflow valve may
be stuck in closed position.
DIAGNOSIS AND TESTING - OVERFLOW VALVE
Fuel volume from the fuel transfer (lift) pump will
always provide more fuel than the fuel injection
pump requires. The overflow valve (a check valve) is
used to route excess fuel through the fuel return line
and back to the fuel tank. Approximately 70% of sup-
plied fuel is returned to the fuel tank. The valve is
located on the side of the injection pump (Fig. 59). It
is also used to connect the fuel return line (banjo fit-
ting) to the fuel injection pump. The valve opens at
approximately 97 kPa (14 psi). If the check valve
within the assembly is sticking, low engine power or
hard starting may result.
If a Diagnostic Trouble Code (DTC) has been stored
for ªdecreased engine performance due to high injec-
tion pump fuel temperatureº, the overflow valve may
be stuck in closed position.
A rubber tipped blow gun with regulated air line
pressure is needed for this test.
(1) Clean area around overflow valve and fuel
return line at injection pump before removal.(2) Remove valve from pump and banjo fitting.
(3) Discard old sealing gaskets.
(4) Set regulated air pressure to approximately 97
kPa (14±16 psi).
(5) Using blow gun, apply pressure to overflow
valve inlet end (end that goes into injection pump).
(6) Internal check valve should release, and air
should pass through valve at 97 kPa (14±16 psi). If
not, replace valve.
(7) Reduce regulated air pressure to 10 psi and
observe valve. Valve should stay shut. If not, replace
valve.
(8) Install new sealing gaskets to valve.
(9) Install valve through banjo fitting and into
pump.
(10) Tighten to 30 N´m (24 ft. lbs.) torque.
REMOVAL
The overflow valve (pressure relief valve) is located
at the outside of fuel injection pump (Fig. 60). It con-
nects the fuel return line (banjo fitting) to the pump.
The valve has no internal serviceable parts and must
be replaced as an assembly. Two sealing gaskets are
used. One gasket is located between pump and banjo
fitting. The other is located between the banjo fitting
and end of valve.
Fig. 58 Overflow Valve Location
1 - FUEL SUPPLY LINE
2 - FUEL RETURN LINE
3 - BANJO BOLT (TEST PORT FITTING)
4 - OVERFLOW VALVE
5 - BANJO FITTING
Fig. 59 Overflow Valve Location
1 - FUEL SUPPLY LINE
2 - FUEL RETURN LINE
3 - BANJO BOLT (TEST PORT FITTING)
4 - OVERFLOW VALVE
5 - BANJO FITTING
14 - 84 FUEL DELIVERY - DIESELBR/BE
OVERFLOW VALVE (Continued)

FUEL DRAIN MANIFOLD
DESCRIPTION
The fuel drain manifold is actually a rifled passage
within the cylinder head (Fig. 62).
OPERATION
When the engine is running, and during injection, a
small amount of fuel flows past the injector nozzle and
is not injected into the combustion chamber. This fuel
is used to lubricate the fuel injectors. Excess fuel
drains into the fuel drain manifold (or passage). Fuel is
drained from this passage into a line at the rear of the
cylinder head (Fig. 62). After exiting the cylinder head,
fuel is routed (returned) back to the fuel tank. A ªTº is
installed into the fuel return line (Fig. 62). This ªTº is
used to allow excess fuel from the injection pump to be
returned into the fuel tank. A one-way check valve
within the overflow valve prevents fuel (from the fuel
drain manifold) from entering the fuel injection pump.
Asmallamount of fuel is returned from the fuel
injectors, while alargeamount (about 70% of sup-
plied fuel) is returned from the fuel injection pump.
REMOVAL
The fuel drain manifold (line) connects a fuel
return passage within the cylinder head to a ªTº fit-
ting on the fuel return line. It is located at the rear
of the cylinder head.(1) Disconnect both negative battery cables at both
batteries.
(2) Remove starter motor. Refer to Group 8B for
procedures.
(3) Disconnect fitting at ªTº (Fig. 63).
(4) Remove banjo bolt at rear of cylinder head.
Discard old sealing washers.
(5) Remove fuel line from vehicle.
(6) Clean connection at rear of cylinder head
before line installation.
INSTALLATION
The fuel drain manifold (line) connects a fuel
return passage within the cylinder head to a ªTº fit-
ting on the fuel return line. It is located at the rear
of the cylinder head.
Servicing fuel return components will not require
air bleeding.
(1) Using new sealing washers, assemble banjo
bolt to fuel line.
(2) Position line to engine and loosely tighten fas-
teners.
(3)
Tighten banjo bolt to 24 N´m (18 ft. lbs.) torque.
(4) Tighten fitting at ªTº to 12 N´m (106 in. lbs.)
torque.
(5) Install starter motor. Refer to 8, Starter for
procedures.
(6) Connect both negative battery cables at both
batteries.
Fig. 62 Fuel Drain Manifold Passage
1 - REAR OF CYLINDER HEAD
2 - BANJO FITTING/BOLT
3 - FUEL RETURN TO TANK
4 - FUEL RETURN LINES
5 - FUEL RETURN LINE FROM PUMP OVERFLOW VALVE
6 - FUEL DRAIN MANIFOLD PASSAGE
7 - ªTº
Fig. 63 Fuel Return Line at Rear of Cylinder Head
1 - REAR OF CYLINDER HEAD
2 - BANJO FITTING/BOLT
3 - FUEL RETURN TO TANK
4 - FUEL RETURN LINES
5 - FUEL RETURN LINE FROM PUMP OVERFLOW VALVE
6 - FUEL DRAIN MANIFOLD PASSAGE
7 - ªTº
14 - 86 FUEL DELIVERY - DIESELBR/BE

DIAGNOSIS AND TESTING - BOOST PRESSURE
Two pressure gauges attached at two different
points are required for this test.(1) Obtain two 6828 fuel pressure test gauges
(equivalent gauges are OK).Gauge Consistency
Test:Connect the gauges together to a common pres-
sure source and verify pressure consistency of both
gauges. Do this consistency test at approximately 206
kPa (30 psi). If pressures are different, they can still
be used for test. Note and record differences in pres-
sures before testing. Make adjustments as necessary.
(2) Remove 3/4º pipe plug fitting at rear of intake
manifold (Fig. 2). Temporarily replace this fitting
with fitting reducer to adapt to pressure gauge.
Note: This pipe plug is located to front of MAP
sensor. Do not remove plug to rear of MAP sen-
sor. This is a COOLANT passage plug.
(3) Loosen hose clamp and disconnect rubber sig-
nal line (Fig. 3) from 1/8º brass fitting at front of tur-
bocharger.
(4) Remove 1/8º brass fitting (Fig. 3) from turbo-
charger. Temporarily replace this fitting with a 1/8º
ªTº fitting to adapt to pressure gauge.
(5) Reattach signal line to temporary ªTº.
(6) Attach first pressure gauge to intake manifold
fitting.
(7) Attach second pressure gauge to ªTº fitting at
turbocharger.
Engine must be at rated RPM and full load for the
test.
If gauge pressure differential is greater than 3 psi
(6 in. Hg), check intercooler and associated piping for
restrictions, plugging or damage.
Maximum pressure at intake manifold (rated rpm
and load) is 36±37 in/hg63 in/hg (17.7±18.2 psi6
1.5 psi).
Wastegate should open at no higher than 38.7
in/hg (19 psi) at wide open throttle, full load. If
wastegate is out of adjustment, a DTC may have
been set. Refer to Wastegate Adjustment in Engines
for adjustment procedures.
Fig. 2 Boost Pressure Test at Intake Manifold
1 - REAR OF INTAKE MANIFOLD
2 - 3/49PIPE PLUG
Fig. 3 Boost Pressure Test at Turbocharger
1 - TURBOCHARGER
2 - 1/89FITTING
3 - SIGNAL LINE
4 - WASTEGATE ACTUATOR
5 - CONTROL ROD
6 - OIL SUPPLY LINE
BR/BEFUEL INJECTION - DIESEL 14 - 89
FUEL INJECTION - DIESEL (Continued)

Always cover or cap any open fuel connections before
a fuel system repair is performed.
Each fuel injector connector tube contains an edge
filter (Fig. 13) that breaks up small contaminants
that enter the injector. The edge filter uses the injec-
tors pulsating high-pressure to break up most parti-
cles so they are small enough to pass through the
injector.The edge filters are not a substitute for
proper cleaning and covering of all fuel system
components during repair.
The bottom of each fuel injector is sealed to the
cylinder head with a1.5mmthick copper shim (gas-
ket) (Fig. 12). The correct thickness shim must
always be re-installed after removing an injector.
Fuel pressure in the injector circuit decreases after
injection. The injector needle valve is immediately
closed by the needle valve spring and fuel flow into
the combustion chamber is stopped. Exhaust gases
are prevented from entering the injector nozzle by
the needle valve.
DIAGNOSIS AND TESTINGÐFUEL INJECTOR
TEST
The fuel injectors are located in the top of the cylin-
der head between the intake/exhaust valves (Fig. 14).
A leaking fuel injector can cause fuel knock, poor
performance, black smoke, poor fuel economy and
rough engine idle. If fuel injector needle valve does
not operate properly, engine may misfire and produce
low power.
A leak in injection pump-to-injector high-pressure
fuel line can cause many of same symptoms as mal-
functioning injector. Inspect for leaks in high-pressure
lines before checking for malfunctioning fuel injector.
WARNING: THE INJECTION PUMP SUPPLIES HIGH-
PRESSURE FUEL OF UP TO APPROXIMATELY
120,000 kPa (17,400 psi) TO EACH INDIVIDUAL
INJECTOR THROUGH HIGH-PRESSURE LINES. FUEL
UNDER THIS AMOUNT OF PRESSURE CAN PENE-
TRATE SKIN AND CAUSE PERSONAL INJURY. WEAR
SAFETY GOGGLES AND ADEQUATE PROTECTIVE
CLOTHING. AVOID CONTACT WITH FUEL SPRAY
WHEN BLEEDING HIGH-PRESSURE FUEL LINES.
WARNING: DO NOT BLEED AIR FROM FUEL SYS-
TEM OF A HOT ENGINE. DO NOT ALLOW FUEL TO
SPRAY ONTO EXHAUST MANIFOLD WHEN BLEED-
ING AIR FROM FUEL SYSTEM.
(1) To determine which fuel injector is malfunc-
tioning, run engine and isolate each cylinder using
DRB scan tool.The DRB scan tool lists the injec-
tor firing order in both cylinder numerical
order (1±2±3±4±5±6), and actual firing order
(1±5±3±6±2±4).
(2) Note RPM drop for each cylinder. As an alter-
native, loosen high-pressure fuel line fitting at fuel
injector connector tube (Fig. 15). Listen for a change
in engine speed. After testing, tighten line fitting to
40 N´m (30 ft. lbs.) torque. If engine speed drops,
injector was operating normally. If engine speed
remains same, injector may be malfunctioning. Test
all injectors in same manner one at a time.
Fig. 14 Fuel Injector Connections
1 - CONNECTOR
2 - O-RING
3 - FERRULE
4 - FITTING
5 - FUEL LINE
6 - INJECTOR
Fig. 15 Inspecting Injector Operation
1 - HIGH-PRESSURE FUEL LINE
BR/BEFUEL INJECTION - DIESEL 14 - 95
FUEL INJECTOR (Continued)

(3) Once injector has been found to be malfunc-
tioning, remove it from engine and test it. Refer to
Fuel Injector Removal/Installation.
WARNING: FUEL INJECTOR TESTERS CAN
DEVELOP EXTREMELY HIGH PRESSURES. FUEL
UNDER THIS AMOUNT OF PRESSURE CAN PENE-
TRATE SKIN AND CAUSE PERSONAL INJURY.
WEAR SAFETY GOGGLES AND ADEQUATE PRO-TECTIVE CLOTHING. AVOID CONTACT WITH FUEL
SPRAY WHEN OPERATING INJECTOR TESTOR.
(4) After injector has been removed, obtain bench-
mount fuel injector tester OTCt(SPXt) part number
4210 (Fig. 16) (or equivalent). Install Special Tool
number 8301 (Fuel Injector Adapter) to 4210 tester.
Install fuel injector into 8301 adapter. Be sure tip of
adapter tool 8301 is aligned to inlet hole at side of
injector (Fig. 17) before tightening tool. Tighten tool
8301 to injector. Position container below injector
before testing.
(5) Refer to operating instructions supplied with
pressure tester for procedures.
(a) Check opening pressure or ªpopº pressure.
Pressure should be approximately 31,026 kPa (310
bars) or (4500 psi6250 psi). If fuel injector needle
valve is opening (popping) too early or too late,
replace injector.
(b) Perform a leak-down test on injector. Apply
pressure with injector tester. The injector should
not leak (drip) fuel with pressure at approximately
20 bars (291 psi) lower than pop pressure.
(c) Operate tester lever quickly several times to
check injector spray pattern. Verify fuel is spraying
from each injector nozzle hole. Injector should also
spray evenly from each nozzle hole.
(d) Pay attention to size and shape of spray
plumes. They should all be equal. If possible, com-
pare spray pattern to that of a new fuel injector
with same part number. Checking each plume for
consistency is an excellent indicator of injector per-
formance. Even if only one nozzle hole is plugged,
significant performance problems could result.
(e) Look for burrs on injector inlet.
(f) Check nozzle holes for hole erosion or plug-
ging.
(g) Inspect end of nozzle for burrs or rough
machine marks.
(h) Look for cracks at nozzle end.
(i) Check nozzle color for signs of overheating.
Overheating will cause nozzle to turn a dark yel-
low/tan or blue (depending on overheating temper-
ature).
(j) Look at end of injector tube where it meets
injector. A small, shiny band should be seen at this
point. The band should have a consistent thick-
ness. If not, injector could be leaking into fuel
return.
(k) If any of these conditions occur, replace injec-
tor.
REMOVAL
The fuel injectors are located in the top of the cyl-
inder head between the intake/exhaust valves (Fig.
18).
Fig. 16 Fuel
1 - FUEL INJECTOR
2 - ADAPTOR TOOL 8301
3 - POP PRESSURE TESTER
Fig. 17 Installing Injector to Adaptor Tool 8301
1 - ADAPTOR TOOL 8301
2 - TIP
3 - FUEL INJECTOR
4 - INLET AT SIDE OF INJECTOR
14 - 96 FUEL INJECTION - DIESELBR/BE
FUEL INJECTOR (Continued)

OPERATION
The sensor located in the Bosch VP44 fuel injection
pump is used to check fuel temperature within the
injection pump and to set a Diagnostic Trouble Code
(DTC) if a specific high fuel temperature has been
reached. If high temperature has been reached,
engine power will be de-rated by the Engine Control
Module (ECM).
The sensor located in the top of the fuel filter hous-
ing is used to control the fuel heater element. Refer
to Fuel Heater Description and Operation for addi-
tional information.
INTAKE AIR HEATER
DESCRIPTION
The intake manifold air heater element assembly
is located in the top of the intake manifold (Fig. 25).
OPERATION
The air heater elements are used to heat incoming
air to the intake manifold. This is done to help
engine starting and improve driveability with cool or
cold outside temperatures.
Electrical supply for the 2 air heater elements is
controlled by the Engine Control Module (ECM)
through the 2 air heater relays. Refer to Intake Man-
ifold Air Heater Relays for more information.
Two heavy-duty cables connect the 2 air heater ele-
ments to the 2 air heater relays. Each of these cables will
supply approximately 95 amps at 12 volts to an individ-
ual heating element within the heater block assembly.
Refer to the Powertrain Diagnostic Procedures
manual for an electrical operation and complete
description of the intake heaters, including pre-heat
and post-heat cycles.
REMOVAL
The 2 intake manifold air heater elements are
attached to a metal block located at the top of the
intake manifold (Fig. 26). If servicing either of the
heater elements, the entire block/element assembly
must be replaced.
(1) Disconnect both negative battery cables at both
batteries.
(2) Disconnect clamp from rubber hose at air
intake housing.
(3) Disconnect rubber hose at air intake housing.
(4) Remove engine oil dipstick tube mounting bolt
(Fig. 28). Position dipstick tube to the side.
(5) Disconnect heater electrical cables at cable
mounting studs (Fig. 28).
(6) Disconnect ground cable bolt and ground cable
from housing (Fig. 27).
(7) Remove 4 housing bolts (Fig. 28).
(8) Remove air intake housing from top of heater
elements.
(9) Remove heater element assembly from intake
manifold.
(10) Clean old gasket material from air intake
housing and intake manifold.
(11) Clean old gasket material from both ends of
heater block (Fig. 26).
Fig. 25 Air Heater Elements Location
1 - AIR HEATER ELEMENTS
2 - LOWER GASKET
3 - BLOCK
4 - UPPER GASKET
Fig. 26 Intake Manifold Air Heater Element Location
1 - AIR HEATER ELEMENTS
2 - LOWER GASKET
3 - BLOCK
4 - UPPER GASKET
14 - 100 FUEL INJECTION - DIESELBR/BE
FUEL TEMPERATURE SENSOR (Continued)