Dodge dakota 2002 Service Manual page 1253

9 - 4 ENGINE - 3.7L
ENGINE - 3.7L (Continued)
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - ENGINE
DIAGNOSIS - INTRODUCTION
Engine diagnosis is helpful in determining the
causes of malfunctions not detected and remedied by
routine maintenance.
These malfunctions may be classified as either per-
formance (e.g., engine idles rough and stalls) or
mechanical (e.g., a strange noise).
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING)—PERFORMANCE and (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)—MECHANICAL for
possible causes and corrections of malfunctions.
(Refer to 14 - FUEL SYSTEM/FUEL DELIVERY -
DIAGNOSIS AND TESTING) and (Refer to 14 -
FUEL SYSTEM/FUEL INJECTION - DIAGNOSIS
AND TESTING) for the fuel system diagnosis.
DIAGNOSIS AND TESTING - ENGINE DIAGNOSIS - PERFORMANCE
CONDITION
ENGINE WILL NOT START
ENGINE STALLS OR ROUGH IDLE
Additional tests and diagnostic procedures may be
necessary for specific engine malfunctions that can
not be isolated with the Service Diagnosis charts.
Information concerning additional tests and diagno-
sis is provided within the following diagnosis:
• Cylinder Compression Pressure Test (Refer to 9 -
ENGINE - DIAGNOSIS AND TESTING).
• Cylinder Combustion Pressure Leakage Test
(Refer to 9 - ENGINE - DIAGNOSIS AND TEST-
ING).
• Engine Cylinder Head Gasket Failure Diagnosis
(Refer to 9 - ENGINE/CYLINDER HEAD - DIAGNO-
SIS AND TESTING).
• Intake Manifold Leakage Diagnosis (Refer to 9 -
ENGINE/MANIFOLDS/INTAKE
DIAGNOSIS AND TESTING).
POSSIBLE CAUSE
1. Weak battery
2. Corroded or loose battery
connections.
3. Faulty starter.
4. Faulty coil or control unit.
5. Incorrect spark plug gap.
6. Incorrect right bank cam timing.
7. Dirt or water in fuel system.
8.Faulty fuel pump, relay or wiring.
9. Faulty cam or crank sensor
1. Vacuum leak.
2. Faulty crank position sensor
3. Faulty coil.
MANIFOLD
CORRECTION
1. Charge or replace as necessary.
2. Clean and tighten battery
connections. Apply a coat of light
mineral grease to the terminals.
3. (Refer to 8 - ELECTRICAL/
STARTING - DIAGNOSIS AND
TESTING).
4. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
5. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/SPARK PLUG
- CLEANING).
6. Refer to engine timing in this
section.
7. Clean system and replace fuel
filter.
8.Repair or replace as necessary.
9. Refer to Ignition system.
1. Inspect intake manifold and
vacuum hoses, repair or replace as
necessary.
2. Replace crank position sensor.
3. (Refer to 8 - ELECTRICAL/
IGNITION CONTROL/IGNITION
COIL - REMOVAL).
DR
-