4TNV98 & 4TNE98 Diesel Engine
Section 8. Troubleshooting
236
Troubleshooting By Measuring
Compression Pressure
Compression pressure drop is one of the major
causes of increasing blow-by gas (engine oil
contamination or increased engine oil consumption
as a resultant phenomenon) or starting failure. The
compression pressure is affected by the following
factors:
1.
Degree of clearance between the piston and
cylinder
2.
Degree of clearance at the intake / exhaust valve
seat
3.
Gas leak from the nozzle gasket or cylinder head
gasket
The pressure will drop due to increased parts wear.
Pressure drop reduces the durability of the engine.
A pressure drop may also be caused by a scratched
cylinder or piston, dust entrance from the dirty air
cleaner element or a worn or broken piston ring.
Measure the compression pressure to determine the
condition of the engine.
Compression Pressure Measurement
Method
1.
Warm up the engine.
2.
Stop the engine. Remove the high-pressure fuel
injection lines as an assembly from the engine.
Remove the fuel injector from the cylinder to be
measured. See Removal of Fuel Injectors on
page 147.
CAUTION
Remove or install the high-pressure fuel
injection lines as an assembly whenever
possible.
Disassembling the high-pressure fuel injection
lines from the retainers or bending any of the
fuel lines will make it difficult to reinstall the fuel
lines.
3.
Turn off the fuel supply valve in the fuel supply
line. Disconnect the fuel injection pump stop
solenoid at the connector. This prevents the fuel
injection pump from injecting fuel during
4.
Before installing the compression gauge
(Figure
14-1, (1))
adapter, crank the engine with the stop
solenoid disconnected for a few seconds to clear
the cylinder of any residual fuel.
5.
Install a nozzle seat at the tip end of the
compression gauge adapter. Install the
compression gauge and the compression gauge
adapter at the cylinder to be measured.
6.
Crank the engine until the compression gauge
reading is stabilized.
Figure 14-1
7.
After performing the compression check remove
the compression gauge and compression gauge
adapter from the cylinder. Reinstall the fuel
injector, high-pressure fuel injection lines, and
reconnect the stop solenoid.
See Reassembly of
Fuel Injectors on page 165.
8.
Turn on the fuel supply valve and reconnect the
injection pump stop solenoid.
9.
Prime the fuel system. Check for leaks. Test the
engine. compression testing.
Summary of Contents for D20G
Page 2: ......
Page 5: ...Specifications TORQUE SPECIFICATIONS SB2004E00 D e c 1 9 9 8 ...
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Page 138: ...Diesel Engine Engine System 124 NOTE The crankshaft must rotate freely by hand 02900058 ...
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Page 341: ...4TNV98 4TNE98 Diesel Engine Section 3 Engine 87 4TNE98 Engine Figure 6 1 ...
Page 423: ...4TNV98 4TNE98 Diesel Engine Section 4 Fuel System 169 Fuel System Components Figure 7 1 ...
Page 477: ...4TNV98 4TNE98 Diesel Engine Section 7 Starter Motor 223 Starter Motor Troubleshooting ...
Page 494: ...4TNV98 4TNE98 Diesel Engine Section 8 Troubleshooting 240 Troubleshooting Charts ...
Page 495: ...4TNV98 4TNE98 Diesel Engine Section 8 Troubleshooting 241 ...
Page 496: ...4TNV98 4TNE98 Diesel Engine Section 8 Troubleshooting 242 ...
Page 498: ...4TNV98 4TNE98 Diesel Engine Section 8 Troubleshooting 244 4TNE98 Engine ...
Page 499: ...Service Manual G424FE LP Engine G424F LP Gasoline Engine G20G G25G G30G SB4320E00 Jan 2008 ...
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Page 529: ...G424F FE Service Manual Chapter 2 Recommended Maintenance 29 ...
Page 534: ...G424F FE Service Manual Chapter 3 Engine Mechanical System 34 MAIN BEARINGS 0 50 UNDERSIZE ...
Page 584: ...G424F FE Service Manual Chapter 3 Engine Mechanical System 84 ...
Page 729: ...G424F FE Service Manual 229 Chapter 8 Basic Troubleshooting ...
Page 731: ...G424F FE Service Manual 231 Chapter 8 Basic Troubleshooting ...
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Page 820: ...Power Train System Operation 14 Hydraulic System ...
Page 822: ...Power Train System Operation 16 Hydraulic System ...
Page 824: ...Power Train System Operation 18 Hydraulic System ...
Page 826: ...Power Train System Operation 20 Hydraulic System ...
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Page 1023: ...A374081 01 ELECTRIC SCHEMATIC MODEL D20 25 30G EM0K2 EM0K3 Cummins B3 3 ...
Page 1024: ...A654030 00 ELECTRIC SCHEMATIC MODEL D20 25 30G EM0QM EM0QN Yanmar 4TNE98 Tier 3 ...
Page 1025: ...A604500 00 ELECTRIC SCHEMATIC MODEL G20 25 30G EM0QF EM0QG GM G424F Non Certi LP ...
Page 1026: ...A604510 00 ELECTRIC SCHEMATIC MODEL G20 25 30G EM0QH EM0QJ GM G424F Non Certi GAS ...
Page 1027: ...A604516 00 ELECTRIC SCHEMATIC MODEL G20 25 30G EM0QY EM0QZ GM G424FE Tier 3 LP ...
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Page 1059: ...Safety Section 29 Lean away from the direction of fall Lean forward ...
Page 1071: ...General Section 41 Typical Example Side Shifter Serial Number If Equipped ...