ENGINE—PERFORMANCE
CONDITION
POSSIBLE CAUSES
CORRECTION
ENGINE WILL NOT
START
1. Weak battery.
1. Test battery specific gravity. Charge or replace as necessary.
2. Corroded or looose battery connections.
2. Clean and tighten battery connections. Apply a coat of light mineral
grease to the terminals.
3. Faulty starter.
3. Refer to Group 8A, Battery/Starter/Charging System Diagnostics.
4. Moisture on ignition wires and distributor
cap.
4. Wipe wires and cap clean and dry.
5. Faulty ignition cables.
5. Replace any cracked or shorted cables.
6. Faulty coil or control unit.
6. Test and replace, if necessary (refer to Group 8D, Ignition System).
7. Incorrect spark plug gap.
7. Set gap (refer to Group 8D, Ignition System).
8. Incorrect ignition timing.
8. Refer to Group 8D, Ignition System.
9. Dirt or water in fuel system.
9. Clean system and replace fuel filter.
10. Faulty fuel pump, relay or wiring.
10. Refer to Group 14, Fuel System.
ENGINE STALLS OR
ROUGH IDLE
1. Idle speed set too low.
1. Refer to Group 14, Fuel System.
2. Idle mixture too lean or too rich.
2. Refer to Group 14, Fuel System.
3. Leak in intake manifold.
3. Inspect intake manifold gasket and vacuum hoses. Replace, if
necessary (refer to Group 11, Exhaust System & Intake Manifold).
4. Worn or burned distributor rotor.
4. Install new distributor rotor.
5. Incorrect ignition wiring.
5. Install correct wiring.
6. Faulty coil.
6. Test and replace, if necessary (refer to Group 8D, Ignition System).
7. EGR valve leaking.
7. Test and replace, if necessary (refer to Group 25, Emissions Control
System).
8. Incorrect cam timing.
8. Refer to Timing Belt Service.
ENGINE LOSS OF
POWER
1. Incorrect ignition timing.
1. Refer to Group 8D, Ignition System.
2. Worn or burned distributor rotor.
2. Install new distributor rotor.
3. Worn distributor shaft.
3. Remove and repair distributor (refer to Group 8D, Ignition System).
4. Dirty or incorrectly gapped spark plugs.
4. Clean plugs and set gap (refer to Group 8D, Ignition System).
5. Dirt or water in fuel system.
5. Clean system and repalce fuel filter.
6. Faulty fuel pump.
6. Install new fuel pump.
7. Incorrect valve timing.
7. Correct valve timing.
8. Blown cylinder head gasket.
8. Install new cylinder head gasket.
9. Low compression.
9. Test compression of each cylinder.
10. Burned, warped or pitted valves.
10. Install new valves.
11. Plugged or restricted exhaust system.
11. Install new parts, as necessary.
12. Faulty ignition cables.
12. Replace any cracked or shorted cables.
13. Faulty coil.
13. Test and replace, as necessary (refer to Group 8D, Ignition System.)
14. Incorrect cam timing.
14. Refer to Timing Belt Service.
ENGINE MISSES ON
ACCELERATION
1. Dirty or gap sets too wide in spark plug.
1. Clean spark plugs and set gap (refer to Group 8D, Ignition System).
2. Incorrect ignition timing.
2. Refer to Group 8D, Ignition System.
3. Dirt in fuel system.
3. Clean fuel system.
4. Burned, warped or pitted valves.
4. Install new valves.
5. Faulty coil.
5. Test and replace, if necessary, (refer to Group 8D, Ignition System).
6. Incorrect cam timing.
6. Refer to Timing Belt Service.
ENGINE MISSES AT
HIGH SPEED
1. Dirty or gap set too wide in spark plug.
1. Clean spark plugs and set gap (refer to Group 8D, Ignition System).
2. Worn distributor shaft.
2. Remove and repair distributor (refer to Group 8D, Ignition System).
3. Worn or burned distributor rotor.
3. Install new distributor rotor.
4. Faulty coil.
4. Test and replace, as necessary (refer to Group 8D, Ignition System).
5. Incorrect ignition timing.
5. Refer to Group 8D, Ignition System.
6. Dirty injector in throttle body.
6. Clean injector.
7. Dirt or water in fuel system.
7. Clean system and replace fuel filter.
8. Incorrect cam timing.
8. Refer to Timing Belt Service.
9 - 12
ENGINE
ZG
DIAGNOSIS AND TESTING (Continued)
Summary of Contents for 1997 Grand Cherokee
Page 6: ...FASTENER IDENTIFICATION 4 INTRODUCTION ZG GENERAL INFORMATION Continued ...
Page 9: ...METRIC CONVERSION ZG INTRODUCTION 7 GENERAL INFORMATION Continued ...
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Page 282: ...COOLING SYSTEM DIAGNOSIS DIESEL ENGINE 7 8 COOLING SYSTEM ZG DIAGNOSIS AND TESTING Continued ...
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Page 284: ...7 10 COOLING SYSTEM ZG DIAGNOSIS AND TESTING Continued ...
Page 285: ...ZG COOLING SYSTEM 7 11 DIAGNOSIS AND TESTING Continued ...
Page 286: ...7 12 COOLING SYSTEM ZG DIAGNOSIS AND TESTING Continued ...
Page 290: ...SERPENTINE DRIVE BELT DIAGNOSIS 7 16 COOLING SYSTEM ZG DIAGNOSIS AND TESTING Continued ...
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Page 423: ...VIC Initial Set Up ZG INSTRUMENT PANEL SYSTEMS 8E 21 SERVICE PROCEDURES Continued ...
Page 424: ...VIC Reset 8E 22 INSTRUMENT PANEL SYSTEMS ZG SERVICE PROCEDURES Continued ...
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Page 1655: ...Fig 3 Oil Lubrication System ZG 5 2L ENGINE 9 57 DESCRIPTION AND OPERATION Continued ...
Page 1684: ...TORQUE 9 86 5 2L ENGINE ZG SPECIFICATIONS Continued ...
Page 1689: ...Fig 3 Oil Lubrication System ZG 5 9L ENGINE 9 91 DESCRIPTION AND OPERATION Continued ...
Page 1723: ...DIAGNOSIS AND TESTING SERVICE DIAGNOSIS DIESEL PERFORMANCE ZG ENGINE 9 3 ...
Page 1724: ...9 4 ENGINE ZG DIAGNOSIS AND TESTING Continued ...
Page 1725: ...ZG ENGINE 9 5 DIAGNOSIS AND TESTING Continued ...
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Page 1729: ...SERVICE DIAGNOSIS DIESEL MECHANICAL ZG ENGINE 9 9 DIAGNOSIS AND TESTING Continued ...
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Page 1731: ...ZG ENGINE 9 11 DIAGNOSIS AND TESTING Continued ...
Page 1762: ...SPECIFICATIONS ENGINE SPECIFICATIONS 9 42 ENGINE ZG ...
Page 1763: ...ZG ENGINE 9 43 SPECIFICATIONS Continued ...
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Page 2122: ...DIAGNOSIS AND TESTING NV231 DIAGNOSIS 21 8 TRANSMISSION AND TRANSFER CASE ZG ...