DODGE RAM 1999 Service Repair Manual

Fig. 21: Transmission Wiring Diagram (Jeep Grand Cherokee)


F - B ASIC T E STIN G - D IE SEL

1999 D odge P ic ku p R 1500
1999 ENGINE PERFORMANCE
CHRY - Basic Diagnostic Procedures - Trucks - Diesel
Ram Pickup
INTRODUCTION
The following diagnostic steps will help prevent overlooking
a simple problem. This is also where to begin diagnosis for a no-start
condition.
The first step in diagnosing any driveability problem is
verifying the customer's complaint with a test drive under the
conditions the problem reportedly occurred.
Before entering self-diagnostics, perform a careful and
complete visual inspection. Most engine control problems result from
mechanical breakdowns or poor electrical connections. Before
condemning the computerized system, perform each test listed in this
article.
Two different module systems are used for powertrain control
of diesel engine. The Engine Control Module (ECM), located on left
side of engine, is used to control the fuel system. See Fig. 1. The
Fuel Pump Control Module (FPCM) located on pump, is a separate
component of ECM.
The Powertrain Control Module (PCM), located at right rear of\
engine compartment, is used for charging system, transmission and
speed control functions. CCD Bus circuits connect the various vehicle
control modules. These circuits are connected between ECM and PCM to
allow communication between modules.
Fig. 1: Locating Fuel System & Various Engine Components
Courtesy of Chrysler Corp.
PRELIMINARY INSPECTION & ADJUSTMENTS

VISUAL INSPECTION
1) Check Water-In-Fuel (WIF) sensor electrical connector for\
corrosion, damaged terminals or wiring and tight fit on engine wiring
harness. WIF sensor is located in bottom of fuel filter/water
separator. See Fig. 1.
2) Check for water in fuel filter/water separator by placing
drain pan below drain tube at fuel filter/water separator. See Fig. 1.
3) With engine not running, rotate handle on drain valve
forward, toward front of vehicle to OPEN position. Drain valve is
located near top of fuel filter/water separator. See Fig. 1. Drain
water from fuel filter/water separator.
4) If no water exists and a clean flow of diesel fuel exists,
rotate handle on drain valve back to CLOSE position. Go to next step.
If water exists, allow water to drain until clean flow of diesel fuel
exists. Rotate handle on drain valve back to CLOSE position. Go to
next step.
5) Verify fuel filter/water separator has been serviced
according to proper service schedule. See SERVICE & ADJUSTMENT
SPECIFICATIONS - TRUCKS article.
6) Check color of Filter Minder. Filter Minder is located on
top cover on air filter housing, just above air filter. DO NOT remove
air filter from air filter housing for inspection. If Yellow disc in
Filter Minder has reached Red zone, remove and inspect air filter. See
Fig. 2 . If air filter is dirty, replace air filter and reset Filter
Minder by pressing rubber button on top of Filter Minder.
NOTE: The Yellow disc in Filter Minder may reach Red zone if air
intake is restricted or air filter has become wet during
heavy rain or snow. If air filter has become wet, allow air
filter to dry during normal engine operation and reset Filter
Minder by pressing rubber button on top of Filter Minder.
7) Ensure intercooler inlet and outlet duct clamps are tight
and front of intercooler is not restricted with dirt. See Fig. 3.
Fig. 2: Identifying Filter Minder Components
Courtesy of Chrysler Corp.

Fig. 3: Locating Intercooler & Components
Courtesy of Chrysler Corp.
8) Ensure connections on both batteries are tight and not
corroded. Ensure the three 32-pin connectors are fully engaged on
Powertrain Control Module (PCM). PCM is located on firewall at
passenger's side rear corner of engine compartment.
9) Check for loose, defective or corroded connections at
intake manifold air temperature sensor. See Fig. 4.
10) Ensure electrical connections on intake manifold air
heater relays and intake manifold air heater are tight and not
corroded. Intake manifold air heater relays are mounted on inner
wheelwell, below driver's side battery. See Fig. 5. Intake manifold
air heater is located between air inlet housing and intake manifold
cover. See Fig. 6.

Fig. 4: Locating Intake Manifold Air Temperature Sensor
Courtesy of Chrysler Corp.

Fig. 5: Locating Intake Manifold Air Heater Relays
Courtesy of Chrysler Corp.

Fig. 6: Locating Intake Manifold Air Heater
Courtesy of Chrysler Corp.
NOTE: Restricted low-pressure fuel lines from fuel tank to fuel
transfer pump, fuel heater and fuel filter/water separator
may cause starting problems and prevent engine from
accelerating. Restricted high-pressure fuel lines from fuel
injection pump to fuel injector may cause starting problems,
poor engine performance and excessive Black smoke.
11) Check all fuel supply and returns lines for damage,
kinking or leakage. Check throttle linkage for binding. Check for a
stretched or disconnected throttle return spring.
12) Ensure all ground connections are tight and free of
corrosion. Ensure accessory drive belt is not damaged or slipping.
Check for loose or defective electrical connection on Crankshaft
Position (CKP) sensor. See Fig. 1.

13) On A/T models, ensure all electrical connectors are clean
and properly connected to electrical plugs on transmission case. On
all models, check for loose or defective electrical connections on
starter and starter solenoid.
MECHANICAL INSPECTION
Compression
Manufacturer does not provide information for checking
compression.
FUEL SYSTEM
AIR IN FUEL SYSTEM
NOTE: Air in the fuel system may cause hard starting, rough
running, excessive smoke, poor engine performance, engine
misfire, poor fuel economy and fuel knock. Air may enter fuel
system whenever fuel supply lines, fuel filter/water
separator, fuel injection pump, fuel injectors or high
-pressure fuel lines are removed or disconnected.
1) Inspect all low-pressure fuel lines from fuel tank to fuel
transfer pump, fuel heater and fuel filter/water separator for signs
of leakage. Inspect all high-pressure fuel lines for signs of leakage.
See FUEL INJECTOR & HIGH-PRESSURE FUEL LINES under FUEL SYSTEM.
2) After repairing fuel leak, bleed air from fuel system. See
FUEL LINE BLEEDING under FUEL SYSTEM in REMOVAL, OVERHAUL &
INSTALLATION - TRUCKS - DIESEL article.
FUEL HEATER
1) Fuel heater is located in fuel filter/water separator. See
Fig. 1 . Fuel heater uses a fuel heater temperature sensor for
controlling operation of the fuel heater.
2) A defective fuel heater may cause excessive wax build-up
in the fuel filter/water separator during cold ambient temperatures.
Wax build-up may cause hard starting, prevent engine from
accelerating, low power, Blue smoke or White smoke. For testing of
fuel heater and fuel heater temperature sensor, see SYSTEM & COMPONENT
TESTING - TRUCKS - DIESEL article.
FUEL HEATER RELAY
Ensure fuel heater relay, located in power distribution
center is installed correctly and that terminals are not corroded. For
fuel heater relay testing, see SYSTEM & COMPONENT TESTING - TRUCKS -
DIESEL article.
FUEL FILTER/WATER SEPARATOR
NOTE: A blocked or restricted fuel filter/water separator may cause
starting problems, prevent engine from accelerating, low
power or White smoke. If an excessive amount of water
collects in filter/separator in a short period of time, it
may be necessary to drain and clean fuel tank.
1) When ignition switch is first turned to ON position,
WATER-IN-FUEL (WIF) warning light should come on for 2 seconds to
perform bulb and wiring circuit test and then go off. WATER-IN-FUEL
(WIF) warning light is located on instrument panel, just below the

tachometer.
2) If WATER-IN-FUEL (WIF) warning light stays on, water
should be drained from fuel filter/water separator. To drain water
from fuel filter/water separator, ensure engine is not running. Place
drain pan below drain tube at fuel filter/water separator. See Fig. 1.
3) Rotate handle on drain valve forward, toward front of
vehicle to OPEN position. Drain valve is located near top of fuel
filter/water separator. See Fig. 1.
4) Allow water to drain until clean flow of diesel fuel
exists. Rotate handle on drain valve back to CLOSE position.
FUEL TRANSFER PUMP
NOTE: A defective fuel transfer pump may cause low power, hard
starting and White smoke. Check fuel transfer pump output
pressure (cranking and starting), pressure drop and fuel
supply.
Fuel Transfer Pump Preliminary Inspection
1) Check for restricted or leaking fuel supply line to fuel
transfer pump or fuel return line located on driver's side of engine.
See Fig. 1 . Repair fuel supply line or fuel return line if restricted
or leaking.
2) Check for fuel leaking from fuel transfer pump. Replace
fuel transfer pump if fuel is leaking. Check fuel transfer pump output
pressure.
Fuel Transfer Pump Output Pressure
1) Clean area around filter fitting plugs, then remove plugs.
See Fig. 7 . Install Test Fittings (AVU1-2). Install Fuel Pressure Test
Gauge (6828) at inlet port. See Fig. 7. To prevent engine starting,
remove fuel injection pump relay, located in power distribution
center.
2) Turn ignition switch to START position. Inlet pressure
should be 5-7 psi. Install fuel injection pump relay. Start engine.
Inlet pressure should be 10 psi. Using a scan tool, clear FTC. FTC may
set when relay is removed. Check pressure drop.
Fig. 7: Checking Fuel Transfer Pump Output Pressure
Courtesy of Chrysler Corp.
Pressure Drop Test
Turn engine off. Move pressure gauge from inlet port to

outlet port. See Fig. 7. Start engine. Outlet pressure should not be
more 5 psi (0.4 kg/cm) less than inlet pressure. If pressure drop is
more than 5 psi (0.4 kg/cm), replace fuel filter and retest pressure.
If pressure drop is less than 5 psi (0.4 kg/cm), check for fuel
supply restriction.
NOTE: Due to very small vacuum specifications, use a scan tool and
Periphal Expansion Port (PEP) module with 0-15 psi transducer\
to perform following test.
Fuel Supply Restriction Test
Ensure transfer pump pressure is okay. Disconnect fuel supply
line at fuel transfer pump inlet. Remove plastic clip from pump inlet
and install in end of fuel supply line. Install 3/8" Adapter Hose
(6631) between fuel supply line and pump inlet. Install transducer
from PEP module to "T" fitting on adapter. Connect scan tool to
module. Start engine. Check vacuum reading with engine at full
throttle with no load. If vacuum reading is less than 6 in. Hg, check
for fuel supply air leaks. If vacuum reading is 6 in. Hg or more,
check fuel line for damage, dents and kinks. Repair as necessary. If
no problem is found, remove fuel module from fuel tank and check for
obstructions. Repair as necessary.
NOTE: A 3' section of 1/4" I.D. clear tubing and a 1/8" NPT fitting
are required for the following test.
Fuel Supply Air Leak Test
Clean area around filter inlet fitting plug, then remove
plug. See Fig. 7. Install 1/8" NPT fitting with 1/4" nipple fitting in
test port. Attach clear hose with a clamp to fitting. Place other end
of hose in a fuel container. Turn ignition switch to START position,
then release to RUN position without starting engine. Fuel transfer
pump should run for 25 seconds. After hose has been purged, watch for
any air bubbles in hose. If no bubbles exist, system is okay. If
bubbles exist, check fuel line, fittings and fuel module in tank.
Repair as necessary.
OVERFLOW VALVE
1) Fuel transfer pump delivers more fuel to fuel injection
pump than needed. Surplus fuel is routed back to fuel tank by overflow
valve. Overflow valve is used to secure fuel return line to side of
fuel injection pump. See Fig. 1. A sticking check valve in the
overflow valve may result in low power. Pressure release is set at 14
psi. (1.0 kg/cm
). If outlet valve is stuck closed, a FTC may set.
2) Clean area around outlet valve and fuel return line.
Remove valve from pump and fitting. Using regulated air pressure, test
valve by blowing into valve inlet. Valve should open at 14-16 psi. (1.
0-1.1 kg/cm
). If valve does not open, replace valve. Reduce air
pressure to 10 psi. (0.7 kg/cm). Valve should close. If valve does
not close, replace valve. Using NEW gaskets, install valve through
banjo fitting into fuel injection pump. Tighten valve to 24 ft. lbs.
(30 N.m).
FUEL INJECTOR & HIGH-PRESSURE FUEL LINES
WARNING: DO NOT allow diesel fuel to contact hot engine when checking
fuel injector, as high exhaust temperatures could cause fire.
Use care when working around high-pressure fuel lines, as
fuel is under extreme pressure and could penetrate skin,
causing personal injury. Wear safety goggles and protective
clothing when checking fuel injectors.