Introduction

NOTE: For current engines, the first two characters of the serial number stand for the engine family and type. LD stands for a naturally aspirated 4.236 Engine. LH stands for a compensated (turbocharged) 4.236 Engine. The next five characters are the parts list number. These five characters are represented by dashes "-" in this module. The next single letter is the country of origin. The next set of numbers is the production serial number, and the last letter is the year of manufacture.

Troubleshooting

Troubleshooting can be difficult. On the pages that follow is a list of possible problems. To make a repair to a problem, make reference to the problems and probable causes.

This list of problems and probable causes will only give an indication of where a possible problem can be and what repairs are needed. Sometimes more or other repair work is needed beyond the recommendations in the list. Remember that a problem is not normally caused by one part, but by the relation of one part with other parts. This list cannot give all possible problems and probable causes. The serviceman must find the problem and its source, then make the necessary repairs.

Fuel System Fault Diagnosis Chart

Fuel Injector Fault Diagnosis Chart (On Engine)

Fuel Injector Fault Diagnosis Chart (On A Nozzle Tester)

Remove Injectors: Always make sure that injectors are not damaged during removal as the valve tips can easily be damaged. Install Injectors: Make sure injector/cylinder head bore and seat are clean. See Testing And Adjusting for injector seal installation. If nozzle body or needle valve are worn or damaged, the nozzle and valve must be replaced.

Troubleshooting Problem List

1. Engine Will Not Start

2. Engine Starts, Runs For A Few Moments, Then Stops.

3. Engine Misfires or Runs Rough

4. Engine Runs Evenly But Loses Power

5. Engine Does Not Have Enough Power

6. Too Much Vibration

7. Combustion Noise

8. Valve Compartment Noise

9. Oil In Cooling System

10. Engine Knock

11. Little Rocker Arm Movement And Too Much Valve Clearance

12. Valve Spring Lock Is Free

13. Oil At The Exhaust

14. Little Or No Valve Clearance

15. Engine Has Early Wear

16. Coolant In Lubrication Oil

17. Too Much Black Or Gray Smoke

18. Too Much White Or Blue Smoke

19. Engine Has Low Oil Pressure

20. Engine Uses Too Much Lubrication Oil

21. Engine Coolant Is Too Hot

22. Exhaust Temperature Is Too High

23. Starting Motor Does Not Turn Or Turns Too Slow.

24. Armature Turns, But Pinion Does Not Engage Flywheel Ring Gear.

25. With Starting Motor On, Pinion Engages Ring Gear, But Engine Does Not Crank (Flywheel Begins To Turn).

26. Starting Motor Continues To Run After Ignition Switch Has Been Released.

27. Pinion Does Not Disengage After Engine Starts To Run.

28. Alternator Does Not Charge

29. Alternator Charge Rate Is Low Or Not Regular

30. Alternator Charges Too Much

31. Alternator Is Noisy

Troubleshooting Problems

Problem 1: Engine Will Not Start

Probable Cause:

1. Fuel Stop Control In NO FUEL Position:

Turn control to RUN position.

2. Fuel Shutoff Solenoid Is Defective:

Replace solenoid.

3. Fuel Tank Is Low, Air In Fuel System:

Fill fuel tank; bleed air from fuel system.

4. Fuel Lift Pump Is Defective:

Remove lift pump; repair or replace as necessary.

5. Fuel Filter, Water Separator Or Lines Are Restricted:

Check fuel supply line, filter and water separator.

6. Fuel Injection Pump Operation Not Correct:

Repair or replace fuel injection pump.

7. Injectors Are Defective:

Repair or replace injectors.

8. Ether Starting Aid Is Defective:

Check, repair or replace if necessary.

9. Valve Clearance And/Or Pump Timing Not Correct:

Check, adjust if necessary.

10. Weak Compression:

With weak compression, starting may be difficult in warm weather, but in cold weather the engine may refuse to start. The number of causes are great: worn liners, piston rings, leakage of valves, etc.

Problem 2: Engine Starts, Runs For A Few Moments Then Stops

Probable Cause:

1. Fuel Supply Line Or Filter Are Restricted:

Repair or replace as necessary.

2. Fuel Lift Pump Operation Not Correct:

Check output of pump, repair or replace.

3. Restriction In The Inlet Or Exhaust System:

Check and remove restrictions.

4. Air In The Fuel System:

Find the air leak in the fuel system and correct it. Bleed the air from the fuel system.

Problem 3: Engine Misfires Or Runs Rough

Probable Cause:

1. Fuel Pressure Is Low:

Make sure fuel tank has enough fuel. Look for leaks or bad bends in the fuel supply line. Check outlet pressure of the fuel lift pump. See Fuel Lift Pump in Specifications.

2. Air In The Fuel System:

Find the air leak in the fuel system and correct it. Bleed the air from the fuel system.

3. Injector Is Defective:

Run engine at the rpm that gives maximum misfiring or rough running. Then, loosen a fuel line nut on the injection line for each cylinder, one at a time. Find the cylinder where loosening the fuel line nut does not change the way the engine runs. Test the fuel injector for that cylinder. Install new parts where needed.

4. Valve Clearance And/Or Pump Timing Not Correct:

Check, adjust if necessary.

5. Fuel Injection Pump Operation Not Correct:

Repair or replace if necessary.

6. Moisture In The Fuel System:

Locate, remove and install new clean fuel.

Problem 4: Engine Runs Evenly But Loses Power

Probable Cause:

1. Injectors Need Repair:

Repair or replace as necessary.

2. Fuel Injection Pump Operation Not Correct:

Repair or replace as necessary.

3. Air Cleaner Restriction:

Clean or replace air cleaner.

4. Fuel Injection Pump Timing Not Correct:

Check and correct.

5. Fuel Lift Pump Installed With Camshaft Lobe On Maximum Lift:

Install fuel lift pump with camshaft lobe on minimum lift and tighten bolts evenly.

6. Loss Of Compression:

Engine needs repairs.

Problem 5: Engine Does Not Have Enough Power

Probable Cause:

1. Bad Quality Fuel:

Remove the fuel from the fuel tank. Install new filter element. Put a good grade of clean fuel in the fuel tank.

2. Fuel Pressure Is Low:

Make sure there is fuel in the fuel tank. Look for leaks or bad bends in the fuel line between fuel tank and fuel lift pump. Look for air in the fuel system. Check outlet pressure of the fuel lift transfer pump. See Fuel Lift Pump in Specifications.

3. Air In The Fuel System:

Refer to Problem 3.

4. Governor Control Linkage Not Adjusted Properly:

Adjust linkage for full travel. Install new parts for those that are damaged or defective.

5. Wrong Valve Clearance:

Adjust according to Specifications.

6. Fuel Injection Nozzle Is Defective:

Refer to Problem 3.

7. Fuel Injection Pump Timing Not Correct:

Check and correct.

Problem 6: Too Much Vibration

Probable Cause:

1. Loose Pulley Bolt(s):

Tighten the bolt(s).

2. Pulley Is Defective:

Install a new pulley.

3. Engine Supports Are Loose, Worn or Defective:

Tighten all mounting bolts. Install new components if necessary.

4. Misfires Or Runs Rough:

Refer to Problem 3.

Problem 7: Combustion Noise

Probable Cause:

1. Bad Quality Fuel:

Remove the fuel from the fuel tank. Install a new filter element. Put a good grade of clean fuel in the tank.

2. Fuel Injection Nozzle Is Defective:

Refer to Problem 3.

Problem 8: Valve Compartment Noise

Probable Cause:

1. Broken Valve Spring(s) Or Locks:

Install new parts as necessary. Broken locks can cause the valve to slide into the cylinder. This will cause a lot of damage.

2. Loose Bolts Holding Rocker Arm Assembly:

Tighten the bolts.

3. Too Much Valve Clearance:

Adjust according to Specifications.

Problem 9: Oil In Cooling System

Probable Cause:

1. Head Gasket Is Defective:

Install a new head gasket.

2. Engine Oil Cooler [C4.236 (Turbocharged) Engines Only] Is Defective:

Replace engine oil cooler.

3. Transmission Cooler Is Defective:

Replace transmission cooler.

Problem 10: Engine Knock

Probable Cause:

1. Main Bearing Failure:

Inspect the main bearings and bearing surface of the crankshaft. Install new parts where necessary.

2. Connecting Rod Bearing Failure:

Inspect the connecting rod bearings and the bearing surface of the crankshaft. Install new parts where necessary.

3. Crankshaft Is Damaged:

Replace the crankshaft. Clean the engine thoroughly.

4. Broken Camshaft:

Replace the camshaft. Clean the engine thoroughly.

Problem 11: Little Rocker Arm Movement And Too Much Valve Clearance

Probable Cause:

1. Not Enough Lubrication:

Check lubrication in valve compartment. There must be a strong flow of oil at engine high rpm, but only a small flow at low rpm. Oil passages must be clean, especially those sending oil to the cylinder head.

2. Rocker Arm Parts Are Worn:

If there is too much wear, install new parts or rocker arms. Adjust valve clearance according to Specifications.

3. End of Valve Stem Is Worn:

If there is too much wear, install new valves. Adjust valve clearance according to Specifications.

4. Too Much Valve Clearance:

Adjust according to Specifications.

5. Push Rods Are Worn:

If there is too much wear, install new push rods. Adjust valve clearance according to Specifications.

6. Tappets (Valve Lifters) Are Worn:

If there is too much wear, install new tappets. Adjust valve clearance according to Specifications.

7. Camshaft Lobes Are Worn:

Check valve clearance. Check for free movement of valves or bent valve stems. Check for tappet wear. Install a new camshaft. Adjust valve clearance according to Specifications.

8. Loose Bolts Holding Rocker Arm Assembly:

Tighten the bolts.

Problem 12: Valve Spring Lock Is Free

1. Broken Locks:

Broken locks can cause the valve to slide into the cylinder. This will cause a lot of damage.

2. Broken Valve Spring(s):

Install new valve spring(s).

Problem 13: Oil At The Exhaust

Probable Cause:

1. Too Much Oil In The Valve Compartment:

Look at both ends of the rocker arm shaft. Be sure that there is a plug in each end.

2. Valve Guides Are Worn:

Reconditioning of cylinder head is needed.

3. Piston Rings Are Worn:

Inspect and install new parts as needed.

4. Turbocharger Piston Ring Seal Broken On Turbine Shaft:

Repair turbocharger.

Problem 14: Little Or No Valve Clearance

Probable Cause:

1. Valve Seat Or Face Of Valve Is Worn:

Reconditioning of cylinder head is needed. Adjust valve clearance according to Specifications.

Problem 15: Engine Has Early Wear

Probable Cause:

1. Dirt In Lubrication Oil:

Remove dirty lubricant oil. Install a new filter element. Put clean oil in the engine.

2. Air Inlet Leaks:

Inspect all gaskets and connections. Make repairs if leaks are found.

3. Fuel Leakage Into Lubrication Oil:

This will cause high fuel consumption and low engine oil pressure. Make repairs if leaks are found. Install new parts where needed. The causes are:

a. Fuel lift pump leaks fuel into the crankcase.

b. Too much dribble leakage at injectors.

c. Injector setting pressure too high.

d. Defective seal at front of fuel injection pump.

Make repairs if leaks are found. Install new parts where needed.

Problem 16: Coolant In Lubrication Oil

Probable Cause:

1. Engine Oil Cooler [C4.236 (Turbocharged) Engines Only] Is Defective:

Replace engine oil cooler.

2. Cylinder Head Gasket Is Defective:

Install a new head gasket. Tighten the nuts and bolts holding the cylinder head, according to Specifications.

3. Crack or Defect in Cylinder Head:

Install a new cylinder head.

4. Crack or Defect in Cylinder Block:

Install a new cylinder block.

Problem 17: Too Much Black Or Dark Gray Smoke

Probable Cause:

1. Not Enough Air For Combustion:

Check air cleaner for restrictions.

2. Bad Fuel Injection Nozzle(s):

Install new fuel injection nozzle(s).

3. Wrong Fuel Injection Timing:

Make adjustment to timing.

Problem 18: Too Much White Or Blue Smoke

Probable Cause:

1. Too Much Lubrication Oil In Engine:

Remove extra oil. Find where extra oil comes from. Put correct amount of oil in engine. Do not put too much oil in engine.

2. Misfires Or Runs Rough:

Refer to Problem 3.

3. Wrong Fuel Injection Timing:

Adjust the timing.

4. Valve Guides Are Worn:

Reconditioning of cylinder head is needed.

5. Piston Rings Are Worn:

Install new parts as necessary.

6. Engine Running Too Cold, Water Temperature Regulator (Thermostat) Stuck or None At All:

Replace water temperature regulator (thermostat).

Problem 19: Engine Has Low Oil Pressure

Probable Cause:

1. Oil Pressure Indicator Or Sender Is Defective:

Install new indicator or sender unit.

2. Dirty Oil Filter:

Check the operation of bypass valve for the filter. Install new oil filter element if needed. Remove dirty oil from engine. Put clean oil in engine.

3. Diesel Fuel In Lubrication Oil:

Find the place where diesel fuel gets into the lubrication oil. See Problem 15. Make repairs as needed. Remove the lubrication oil that has diesel fuel in it. Install a new oil filter element. Put clean oil in the engine.

4. Too Much Clearance Between Rocker Arm Shaft And Rocker Arms:

Check lubrication in valve compartment. Install new parts as necessary.

5. Oil Pump Suction Pipe Is Defective:

Replace the pipe.

6. Relief Valve For Oil Pump Does Not Operate Correctly:

Clean valve and housing. Install new parts as necessary.

7. Oil Pump Is Defective:

Repair or replace the oil pump.

8. Too Much Clearance Between Crankshaft And Crankshaft Bearings:

Install new crankshaft and crankshaft bearings if necessary.

9. Too Much Clearance Between Camshaft And Camshaft Bearing:

Install new camshaft and camshaft bearing if necessary.

Problem 20: Engine Uses Too Much Lubrication Oil

Probable Cause:

1. Too Much Lubrication Oil In Engine:

Remove extra oil. Find where extra oil comes from. Put correct amount of oil in engine. Do not put too much oil in engine.

2. Oil Leaks:

Find oil leaks. Make repairs as needed.

3. Turbocharger Oil Seal Fails:

Repair turbocharger.

4. Valve Guides Are Worn:

Reconditioning of cylinder head is needed.

5. Piston Rings Are Worn:

Install new parts as necessary.

Problem 21: Engine Coolant Is Too Hot

Probable Cause:

1. Restriction To Air Flow Through Radiator:

Remove all restrictions of flow.

2. Not Enough Coolant In System:

Add coolant to cooling system.

3. Pressure Cap Is Defective:

Check operation of pressure cap.

4. Combustion Gases In Coolant:

Find out where gases get into the cooling system. Make repairs as needed.

5. Water Temperature Regulator (Thermostat), Temperature Indicator Or Sender Are Defective:

Check water temperature regulator (thermostat) for correct operation. Install new temperature indicator or sender unit.

6. Water Pump Is Defective:

Repair or replace water pump.

7. Too Much Load On The System:

Reduce the load.

8. Wrong Fuel Injection Timing:

Adjust the timing.

9. Drive Belt Is Loose:

Adjust the drive belt.

Problem 22: Exhaust Temperature Is Too High

Probable Cause:

1. Air Inlet Or Exhaust System Is Restricted:

Remove restriction.

2. Wrong Fuel Injection Timing:

Adjust the timing.

3. Turbocharger Is Restricted:

Repair or replace turbocharger.

Problem 23: Starting Motor Does Not Turn

Probable Cause:

1. Battery Has Low Output:

Check condition of battery. Charge battery or replace as necessary.

2. Wiring Or Switch Is Defective:

Make repairs or replace as necessary.

3. Starting Motor Solenoid Is Defective:

Install a new solenoid. Repair or replace the starting motor.

Problem 24: Armature Turns, But Pinion Does Not Engage Flywheel Ring Gear

Probable Cause:

1. Pinion Drive Is Defective:

Replace pinion drive clutch.

2. Damaged Flywheel Ring Gear:

Replace flywheel ring gear.

3. Damaged Or Broken Shift Lever:

Replace shift lever.

4. Damaged Or Broken Solenoid:

Replace solenoid.

Replace armature or idler gear or overrunning clutch as needed.

Problem 25: With Starting Motor On, Pinion Engages Ring Gear, But Engine Does Not Crank (Flywheel Begins To Turn)

Probable Cause:

1. Low Battery:

Charge Battery.

2. Not Enough Brush Pressure On Commutator:

Check brush spring tension. Check brushes and clean or replace them.

3. The Relay That Is Mounted Away From The Starting Motor Is Defective:

Replace relay.

4. Excessive Voltage Drop In Cables:

Check cables and their connections.

5. Clutch Section Of Pinion Drive Slips:

Replace pinion drive.

Problem 26: Starting Motor Continues To Run After Ignition Switch Has Been Released

Probable Cause:

1. Defective Ignition Switch, Solenoid Or Relay:

Replace ignition switch, solenoid or relay.

Problem 27: Pinion Does Not Disengage After Engine Starts To Run

Probable Cause:

1. Solenoid Return Spring Weak Or Broken:

Replace solenoid return spring.

2. Shift Lever Is Binding Or Broken:

Find cause of binding. Replace the shift lever if broken.

3. Defective Ignition Switch Or Relay:

Replace ignition switch of relay.

Problem 28: Alternator Does Not Charge

Probable Cause:

1. Loose Drive Belt For alternator:

Adjust the alternator drive belt.

2. Loose Alternator Drive Pulley:

Check the pulley for wear. If it is worn, install a new pulley. Tighten the pulley nut to the correct torque shown in Specifications.

3. Charging Or Ground Return Circuit Or Battery Connections Are Defective:

Inspect all cables and connections. Clean and tighten all connections. Replace defective parts.

4. Rotor Field Winding Or Regulator Is Defective:

Replace the rotor or regulator.

Problem 29: Alternator Charge Rate Is Low Or Not Regular

Probable Cause:

1. Loose Drive Belt For Alternator:

Adjust the alternator drive belt.

2. Loose Alternator Drive Pulley:

Check the pulley for wear. If it is worn, install a new pulley. Tighten the pulley nut to the correct torque shown in Specifications.

3. Charging Or Ground Return Circuit Or Battery Connections Defective:

Inspect all cables and connections. Clean and tighten all connections. Replace defective parts.

4. Regulator Is Defective:

Replace the regulator.

5. Rectifier Is Defective:

Replace the rectifier.

6. Brushes Are Worn Or Dirty:

Replace the brushes.

Problem 30: Alternator Charges Too Much

Probable Cause:

1. Alternator Or Regulator Has Loose Connections:

Tighten all connections to alternator or regulator.

2. Regulator Is Defective:

Replace the regulator.

Problem 31: Alternator Is Noisy

Probable Cause:

1. Drive Belt For Alternator Is Worn Or Defective:

Install a new drive belt for the alternator.

2. Loose Alternator Drive Pulley:

Check the pulley for wear. If it is worn, install a new pulley. Tighten the pulley nut to the correct torque shown in Specifications.

3. Drive Belt And Drive Pulley For Alternator Are Not In Alignment:

Make an adjustment to put the drive belt and drive pulley in correct alignment.

4. Alternator Bearings Are Worn:

Replace the bearings in the alternator.

Fuel System

Fuel System Bleeding Procedure

Use one of the following procedures to bleed air from the fuel system.

Priming Pump Procedure

A hand primer is also a function of the fuel lift pump. The hand primer is used to fill the fuel system and filters and to bleed air from the fuel system after filters are serviced, fuel lines have been disconnected, or after running out of fuel. Check valves in the primer body prevent fuel from draining out of the system while engine is not running.

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Always use a board or cardboard when checking for a leak. Escaping fluid under pressure, even a pinhole size leak can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your body, it must be removed surgically within a few hours by a doctor familiar with this type of injury.

Fuel Filter
(1) Banjo bolt.

1. Loosen fuel filter banjo bolt (1). Operate priming lever (5) on the fuel lift pump until fuel flows, free of air bubbles around the threads. Tighten the bolt. If the cam lobe on the camshaft that drives the fuel lift pump is on maximum lift, priming lever (5) will not work. Turn the engine until priming lever (5) can be operated.

2. Turn the key start switch ON. Loosen fuel inlet fitting (4) at the injection pump and operate priming lever (5) on the fuel lift pump. When fuel flows freely with no air around the threads, tighten fitting (4) to a torque of 13.3 N·m (120 lb in).

Fuel Injection Pump
(2) Governor vent screw. (3) Hydraulic head vent screw. (4) Fuel inlet fitting.

Fuel Lift And Priming Pump
(5) Priming lever.

3. Loosen hydraulic head vent screw (3) on the side of the pump body.

4. Loosen vent screw (2) on the front side of the governor control housing.

5. Operate priming lever (5) on fuel lift pump until fuel flows free of air bubbles from screws (2) and (3). Tighten governor vent screw (2) first and then hydraulic head vent screw (3). Tighten the screws to a torque of 4.6 N·m (40 lb in).

Fuel Lines
(6) Fuel line nuts.

6. Turn key switch OFF. Loosen nuts (6) at nozzle ends of two fuel injection lines.

7. Set the accelerator at the full open position and make sure the shutoff control is in the RUN position.

8. Turn the engine with the starting motor until fuel, free from air bubbles, flows from both nuts (6) of the fuel injection lines.

See the Starting Motor Cranking Procedure that follows.

9. Tighten nuts (6) of the fuel injection lines to a torque of 20 N·m (15 lb ft).

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NOTICE
Never close a return line of the fuel system while the engine is running. Damage can be caused to the fuel injection pump.

10. The engine should start. If it does not, repeat Steps 1-10.

Starting Motor Priming Procedure

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Always use a board or cardboard when checking for a leak. Escaping fluid under pressure, even a pinhole size leak can penetrate body tissue, causing serious injury, and possible death. If fluid is injected into your body, it must be removed surgically within a few hours by a doctor familiar with this type of injury.

1. Loosen the fuel line retaining nut at the nozzle on cylinder number 3.

2. Position the throttle lever at approximately one-half throttle.

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NOTICE
To prevent overheating of the starting motor, use only the machine's batteries for cranking the engine.

3. Turn the engine with the starting motor until fuel, free from air bubbles, flows from fuel line retaining nut at cylinder number 3.

See the Starting Motor Cranking Procedure that follows.

4. Stop the engine. Retighten the fuel line retaining nut at cylinder number 3 to a torque of 20 N·m (15 lb ft).

Starting Motor Cranking Procedure

1. Crank the engine for no more than 30 seconds.

2. Wait 2 minutes.

3. Repeat Steps 1 and 2 six times, for a total of seven 30-second cranking cycles.

4. Wait for 30 MINUTES.

5. Crank the engine for no more than 30 seconds.

6. Wait 2 minutes.

7. Repeat Steps 5 and 6 three times, for a total of four 30-second cranking cycles.

8. Wait 30 MINUTES.

9. Do Steps 5 through 8 as needed.

Fuel Injection Pump Timing

Timing Fixture Method

Engine Checking Angle

To check the timing mark on the engine timing housing, use the 6V2189 Timing Fixture and proceed as follows:

NOTE: When a new timing housing is installed, it will not have a timing mark on it and will have to be marked for correct alignment with the timing mark on the fuel injection pump.

1. Remove the valve cover from the engine.

NOTE: Direction of normal rotation of engine is counterclockwise from the flywheel end, or clockwise rotation from the front of the engine.

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Personal injury could result if the engine should start while this procedure is done. Do not turn the engine with the starting motor. Turn the key start switch OFF and disconnect the battery and turn the crankshaft by hand.

Timing Pointer Location
(1) Timing pointer. (2) Crankshaft pulley.

2. Turn the crankshaft (by hand; not the starting motor) in the direction of engine rotation until the No. 1 cylinder is at top center (TC) on the compression stroke. The engine will be at TC when the valves of the No. 4 cylinder are in the position of valve overlap (the period between the opening of the inlet valve and the closing of the exhaust valve) and also when timing pointer (1) is lined up with the single timing mark on crankshaft pulley (2).

6V2189 Timing Fixture
(3) Adapter ring. (4) Indicator. (5) Screw. (6) Screw. (7) Screw. (8) Splined shaft.

Adapter
(9) Adapter.

Fuel Pump Drive Gear
(10) Fuel pump drive gear. (11) Dowel.

Adapter Mounted To Fuel Pump Drive Gear
(9) Adapter.

3. Remove the fuel injection pump and the fuel pump drive gear cover. Install adapter (9) of the 6V2189 Timing Fixture into the back of the timing housing and put dowel (11) of fuel pump drive gear (10) in alignment with the groove in adapter (9). Tighten adapter (9) to fuel pump drive gear (10). The adapter splined shaft will point toward the back of the engine.

Fuel Injection Pump Timing Charts:

4. Loosen screw (7), and remove splined shaft (8) from the timing fixture.

5. Make sure the groove in indicator (4) points to the front of the timing fixture. Keep indicator (4) back away from the front of the tool. Make sure the flat of the washer behind screw (5) is over indicator (4).

6. Loosen screw (6) and set the bracket so the chamfered edge is in alignment with the engine checking angle that matches the code letters on the fuel injection pump nameplate. See the Fuel Injection Pump Timing Charts.

Timing Mark Check

7. Push fuel pump drive gear (10) and adapter (9) to the rear and put the splined shaft and the adapter in the matching splines of the timing fixture.

8. Move the timing fixture and adapter forward until the timing fixture is positioned in the timing housing. If indicator (4) is 180° off, the engine is not on the correct stroke. Remove the timing fixture and set the engine on the correct stroke.

9. Move indicator (4) forward to the rear face of the timing housing.

10. Remove timing gear backlash by turning the timing fixture against (opposite) fuel pump rotation (as shown by arrow on fuel injection pump nameplate). Check the location of the timing mark. It must be in alignment with indicator (4). If it is not, remove the old mark, and put a new one on the timing housing that lines up with indicator (4). (A mark will have to be put on a new timing housing.)

NOTE: Be sure to remove the old mark if a new one is put on the timing housing.

11. Remove the timing fixture and adapter (9). Install the fuel injection pump.

Fuel Pump Marking Angle

To check the fuel injection pump timing mark location, the 6V2189 Timing Fixture is again needed. Remove the fuel injection pump and do the procedure that follows.

6V2189 Timing Fixture
(3) Adapter ring. (4) Indicator. (5) Screw. (6) Screw. (7) Screw. (8) Splined shaft.

1. Loosen screw (7), and install splined shaft (8) with the smaller diameter splines to the back of the timing fixture.

2. Make sure the groove in indicator (4) points to the rear of the timing fixture. Keep indicator (4) back away from the rear of the tool. Make sure the flat of the washer behind screw (5) is over indicator (4).

3. Loosen screw (6) and set the bracket so the chamfered edge is in alignment with the fuel pump marking angle that matches the code letters on the fuel injection pump name plate. See the Fuel Injection Pump Timing Charts.

4. With adapter ring (3) in position between timing fixture and fuel injection pump, install splined shaft (8) and the timing fixture into the hub of the fuel injection pump. Push timing fixture up against the pump to lock the timing fixture in position with screw (7). The timing fixture will only fit on the fuel injection pump one way due to a missing spline of the pump and timing fixture.

Fuel Injection Pump Timing Mark Check
(14) 5P4721 Tube. (15) 5P4150 Nozzle Tester.

5. Connect 5P4150 Nozzle Tester (15), 5P4721 Tube (14) and the 5P4718 Adapter to No. 1 cylinder outlet connection on the fuel injection pump marked "W". Operate the 5P4150 Nozzle Tester to have 3030 kPa (440 psi) indication on the gauge.

6. Turn the fuel injection pump in the direction of normal rotation (shown on nameplate of pump) until it won't move (locks).

7. In this position, slide indicator (4) until it is half way over the fuel injection pump flange. The mark on the pump flange must be in alignment with the groove of indicator (4). If it is not, make a new mark on the fuel injection pump flange. Be sure to remove the old mark if a new one is put on the flange.

8. Remove the timing fixture, and install the fuel injection pump.

Valve Drop Method

The procedure that follows is another method of fuel injection pump timing.

Alignment Of Letter On Rotor To Circlip

This procedure is a check to be sure the circlip (snap-ring) is in the correct position in relation to the timing letter on the pump rotor. This must be done before the fuel injection pump timing procedure is done. The letter "C" is for this fuel injection pump.

1. Remove the fuel injection pump from the engine.

2. Connect the 5P4150 Nozzle Tester, 5P4721 Tube and a 5P4718 Adapter to No. 1 cylinder outlet connection (marked "W") on the fuel injection pump.

3. Operate the 5P4150 Nozzle Tester to have 3030 kPa (440 psi) indication on the gauge.

4. Turn the injection pump by hand in direction of normal rotation (arrow indication is on the pump) until it will not turn (locks up).

5. Remove the cover to give access to the letter on the rotor.

Rotor To Circlip Alignment

6. Check the location of the scribed line on the pump rotor with the letter "C" in relation to the square end of the circlip. They must both be in alignment. If not, carefully move the circlip until they are in alignment. The pump is now at the beginning of injection for the No. 1 cylinder (static timing point).

7. Install the access cover.

8. Remove the Nozzle Tester from the pump. Install the fuel injection pump on the engine.

Timing Procedure

1. Be sure the fuel injection pump is correctly installed with the mark on the timing gear housing in alignment with the mark on the flange of fuel injection pump housing.

NOTE: Direction of normal rotation of engine is counterclockwise from flywheel end, or clockwise rotation from front of engine.

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Personal injury could result if the engine should start while this procedure is done. Do not turn the engine with the starting motor. Turn the key start switch OFF and disconnect the battery and turn the crankshaft by hand.

Timing Pointer Location
(1) Timing pointer. (2) Crankshaft pulley.

2. Remove the valve cover. Turn the crankshaft (by hand; not the starting motor) in the direction of engine rotation until the No. 1 cylinder is at top center (TC) on the compression stroke. The engine will be at TC when the valves of the No. 4 cylinder are in position of valve overlap (the period between the opening of inlet valve and closing of exhaust valve) and also when timing pointer (1) is lined up with the single timing mark on the crankshaft pulley (2).

3. Remove the rocker shaft assembly from the cylinder head.

Valve Spring Compression

4. Make a compression of the inlet valve springs for the No. 1 cylinder with the 7F4292 Valve Spring Compressor Group.

5. Remove the collets, spring cap and springs from the inlet valve of No. 1 cylinder and let the valve be on top of the piston.

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NOTICE
Be sure No. 1 piston is at TC on compression stroke. If piston is not in this position, the valve can drop into the chamber and the cylinder head has to be removed to get the valve.

Piston Displacement Check
(3) Dial indicator.

6. Fasten 8T5096 Dial Indicator Group (3) so it is in contact with the end of the No. 1 inlet valve as shown. Adjust the dial indicator so it has "zero" indication.

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NOTICE
Do not turn the crankshaft too quickly or too far because the valve could drop into the piston chamber.

7. To remove backlash from the timing gears, very slowly, turn the crankshaft by hand opposite the direction of rotation approximately 1/8 of a turn.

8. Now, slowly turn the crankshaft in normal rotation to the proper piston displacement as shown in the Fuel Injection Pump Timing Charts. The fuel injection pump code letters are on the pump nameplate.

Fuel Injection Inspection Cover
(4) Inspection cover.

9. Remove the wire and seal and slowly remove inspection cover (4) on the side of the fuel injection pump to have visible access to the rotor.

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NOTICE
The fuel injection pump is full of fuel. Have a container ready to hold the fuel when the inspection cover is removed.

10. The scribed line on the pump rotor with the letter "C" must be in alignment with the square end of circlip (5). If they are not in alignment, loosen the three nuts that fasten the pump housing to the timing gear housing.

Timing Marks Location In Pump Housing
(5) Circlip (snap ring).

11. Turn the pump housing until the scribed line with the letter "C" and straight edge of circlip are in alignment. Tighten the three nuts that hold the pump housing. If the pump has been turned, remove the old timing mark on the timing gear housing, and put a new one on the housing that will be in alignment with the mark on the fuel injection pump flange.

12. Install inspection cover (4) on the pump housing. Install a new wire and seal with the 5P1660 Governor Sealing Tool Group.

13. Remove the dial indicator. Compress the valve springs with the 7F4292 Valve Spring Compressor Group. Install the valve springs (damper coils of springs toward cylinder head), spring cap and collets on the inlet valve. Be sure the spring cap is in correct position on the springs.

14. Install the rocker shaft assembly. Tighten the bolts to a torque of 43 N·m (32 lb ft). Adjust the valves. See Valve Lash (Clearance) Adjustment in Testing and Adjusting.

15. Bleed the air from the fuel system.

See Fuel System Bleeding Procedure in Testing and Adjusting.

Fuel Injection Pump Installation

1. Install the fuel injection pump in its location on back of the timing gear housing. Be sure the slot in the pump hub is in alignment with dowel (1) in the gear.

Alignment Of Marks

2. Put the pump in position so the scribed line on the pump flange is in alignment with the mark on the timing gear housing.

Fuel Injection Pump Installation
(1) Dowel. (2) Setscrew.

3. Fasten the drive gear to the pump shaft with three setscrews (2) and washers. Be sure dowel (1) is in correct location in its slot.

4. Install the inspection cover on the timing gear housing.

5. Connect the fuel lines to the pump.

6. Connect the governor lever control linkage and the fuel shutoff solenoid wire connector.

7. Bleed the fuel system.

See Fuel System Bleeding Procedure in Testing and Adjusting.

High And Low Idle Speed Adjustments

The wire seal for the high idle speed screw of the original fuel injection pump must not be broken or moved in any way unless factory approved. Failure to do so may result in the warranty becoming void.

High And Low Idle Adjustment
(1) Low idle screw. (2) Accelerator lever. (3) High idle screw sleeve.

When a replacement fuel injection pump is installed or if the high idle speed adjustment screw was moved, the high idle speed must be checked and set again as necessary in vehicle.

1. Put the transmission in NEUTRAL. Activate the parking brake.

2. Be sure the accelerator lever nut is tightened to a torque of 3.4 ± 0.2 N·m (30 ± 2 lb in).

Use the 6V3121 Multitach Group to check the low and high idle speeds. Special Instruction Form No. SEHS7807 is included with the group. Do the procedure that follows to check and adjust the idle speeds.

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To prevent personal injury, be sure there is good ventilation for the exhaust. Keep hands away from moving parts of the engine during this procedure.

6V3121 Multitach Group

3. Connect the 6V3121 Multitach Group as follows:

a. Put one piece of 6V0093 Reflective Tape 19.1 mm (.75 in) long on the outer circumference of the crankshaft pulley.

b. Connect the power cable and photohead cable to the multitach.

c. Connect either clip of the power cable to the chassis. Connect the other clip to the positive (+) post of the battery.

d. Fasten the photohead (with the magnetic base) close to the engine so the light beam hits the tape on the crankshaft pulley. Start the engine.

e. Push the PH key so the PHOTO INPUT light goes on.

f. Push the P/REV key to show pulses per revolution. This number will show on the display, off and on. The pulses per revolution should be the same as the number of pieces of tape on the crankshaft pulley, which is one.

g. If 1 does not show on the display, push the CLR key, then push the 1 key.

h. Push the R/MIN key and read revolutions per minute.

4. Run the engine at fast idle speed until the temperature of normal operation is reached.

5. Let the engine go back to low idle. The low idle speed should be 750 ± 30 rpm. Adjust screw (1) if necessary to get the correct low idle speed in vehicle.

6. Run the engine at high idle speed. The high idle speed should be 2600 ± 100 rpm. If an adjustment is necessary, remove the wire, seal and sleeve (3). Adjust the screw to get the correct high idle speed in vehicle.

7. Install the sleeve and a new wire and seal with the 5P1660 Governor Sealing Tool Group.

Governor Control Adjustment

Governor Control Adjustment
(1) Hand control lever. (2) Rod end at fuel injection pump. (3) Fuel injection pump lever. (4) Nuts. (5) Hand control override lever. (6) Shaft lever. (7) Locknut. (8) Rod end at override lever. (9) Pedal lever. (10) Stop bolt. (11) Pedal.

Do the procedure that follows to adjust the governor control linkage.

1. Put hand control lever (1) against the low idle stop.

2. Adjust hand override lever (5), using rod end (8), until the clearance between lever (5) and shaft lever (6) is 0 to 1 mm (0 to .04 in). Pedal lever (9) must contact cab floor to make the above adjustment.

3. Adjust rod end (2) until it fits easily into the hole of throttle lever (3) of the fuel injection pump. Then turn rod end (2) counterclockwise one turn from the front of the machine to put a preload on the low idle stop. Attach the rod end of the fuel injection pump.

4. Push pedal (11) down until fuel pump lever (3) contacts the high idle stop and overtravel of rod end (2) begins. Turn stop bolt (10) until it contacts pedal lever (9), and tighten the locknut. The fuel injection pump rod end overtravel should be 2 to 6 mm (.08 to .24 in).

5. Put hand control lever (1) in the high idle position. It should stay in the selected position. If it does not, tighte locknut (7) until it does.

6. Check to see if low and high idle are obtained with hand control lever (1) and pedal (11).

7. Pedal height may be adjusted by loosening nuts (4), repositioning them and tightening them again.

Fuel Injector Problems

Problem: Fuel Injector Nozzle Does Not Make Vibration Sound While Injecting

Probable Cause:

1. Needle Too Tight, In A Bind, Or Needle Seat Leaks: Clean nozzle. Inspect nozzle cap nut. Replace parts as necessary.

Problem: Too Much "Leak-Off"

Probable Cause:

1. Nozzle Needle Loose:

Replace parts are necessary.

2. Nozzle Nut Not Tight:

Tighten nut to correct torque.

3. Foreign Material Between Contact Faces Of Nozzle And Holder:

Clean.

Problem: Nozzle "Blueing"

Probable Cause:

1. Installation Not Correct, Tightened Too Tight Or Not Cooled Correctly:

Replace parts as necessary. Find cause of failure.

Problem: Nozzle Opening Pressure Too High Or Too Low

Probable Cause:

1. Correct Shims Need To Be Installed:

Adjust nozzle to correct pressure.

2. Needle Stuck (Seized) Or Dirty:

Clean nozzle.

3. Nozzle Openings Are Restricted:

Clean nozzle.

Problem: Nozzle Pressure Too Low

Probable Cause:

1. Nozzle Spring Broken:

Replace parts and adjust pressure.

Problem: Nozzle Drips (Leaks)

Probable Cause:

1. Nozzle Leak Because Of Carbon Deposit; Needle Stuck:

Clean nozzle. If this does not correct problem, replace parts as necessary.

Problem: Spray Pattern Has Distortion

Probable Cause:

1. Nozzle Has Dirt, Carbon Deposit:

Clean nozzle.

2. Nozzle Needle Is Damaged:

Replace nozzle.

Fuel Injector Tests

To find out which fuel injectors do not work correctly, do the procedure as follows:

1. Start the engine and run it at low idle speed.

Fuel Injection Lines
(1) Fuel injection line nut.

2. Loosen fuel injection line nut (1) at each fuel injector and listen for the idle to become rough (not smooth) at each cylinder.

3. If the idle does not decrease or become rough when fuel injection line nut (1) is loosened, then that injector has a defect and must be removed for more tests.

Clean Fuel Injectors

Before an injector is tested, remove any loose carbon from the tip of the nozzle.

1. Fasten the fuel injector in a holder or a vise with brass jaws. Remove the nozzle cap nut and nozzle with the correct size wrench.

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NOTICE
Do not use the brush enough to cause damage to the body of the nozzle.

2. Remove the needle from the nozzle body. Use the 8S2258 Brass Wire Brush and remove any carbon that may be on the nozzle body.

3. Clean nozzle body seat and the fuel reservoir with an 8S2255 Scraper.

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NOTICE
Use extra care not to break a cleaning wire off in a hole because removal is almost impossible.

4. Clean the holes in the nozzle tip with a cleaning wire. If the size is not known, carefully try different sizes to find the correct one.

5. The cleaning wire must be installed into the hole and slowly rotated to clean.

NOTE: It is important that extra care be used with the nozzle needle to prevent damage because a scratch or burr could cause needle leakage or spray distortion.

Pressure Adjustment

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When testing a fuel injection nozzle, keep the tip of the nozzle pointed away from the operator and into the 8S2270 Fuel Collector. Fuel (spray) from the orifices in the tip of the nozzle is under high pressure can can cause injury to the operator. Keep hands away from the nozzle.

Nozzle Tester
(1) Fuel injector (atomiser). (2) 5P4721 Tube. (3) FT1384 Extension. (4) 5P4718 Adapter. (5) 8S2270 Fuel Collector. (6) 5P4150 Nozzle Tester.

1. Connect fuel injector (1) to 5P4150 Nozzle Tester (6), 5P4721 Tube (2) and 5P4718 Adapter (4). Put the fuel injector in position so the fuel spray will be directed into FT1384 Extension (3) and 8S2270 Fuel Collector (5).

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NOTICE
Be sure to use clean SAE J-967 oil or Kent-Moore J-26400-5 when testing. Dirty test oil will damage components of the fuel injection nozzle.

Reference: Kent-Moore J-26400-5 calibration oil can be purchased from Kent-Moore Tool Division, 28635 Mound Road, Warren, Michigan 48066, Attn: Diesel Products Order Desk.

2. Close the gauge protector valve. Close the on-off valve. Open the pump isolator valve. Flush the fuel injection nozzle by operating the nozzle tester for 10 to 15 strokes at a rate of 60 strokes per minute.

3. Open the gauge protector valve. Make a slow increase to the pressure (operate the pump lever) until the valve in the fuel injection nozzle opens. Make note of the highest pressure indication on the gauge before the pointer (flicks) has a fast movement. This indication is the pressure at which the needle is lifting from its nozzle seat or opening pressure.

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NOTICE
Before the injector is removed from the tester, be sure the gauge protector valve is closed to prevent damage to the pressure gauge.

4. The injector identification code is HL. The correct opening pressure is 23 335 kPa (3380 psi). If the opening pressure is not correct, remove the fuel injector from the nozzle tester.

Fuel Injector
(7) Fuel injector body. (8) Shims. (9) Spring. (10) Spring seat. (11). Adapter plate. (12) Nozzle valve. (13) Nozzle cap nut.

5. Remove nozzle cap nut (13), spring seat (10), spring (9) and shims (8) from injector body (7). Make sure that adapter plate (11) and nozzle valve (12) do not fall out of nut (13).

6. Add or remove shims (8) to get the correct opening pressure as shown in the shim adjustment chart. The shim part numbers and corresponding codes are shown in the chart that follows.

Example: If the opening pressure is 610 kPa (88 psi) too high (above nominal), then remove all the shims and install shim packs B&H. If the opening pressure is 610 kPa (88 psi) too low (below nominal), then remove all shims and install shim packs B&L.

7. Assemble the injector. Tighten nozzle cap nut (13) to a torque of 47.5 N·m (420 lb in).

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NOTICE
Before the injector is removed from the tester, be sure the gauge protector valve is closed to prevent damage to the pressure gauge.

8. Check opening pressure again on the nozzle tester. If the pressure is correct, remove the injector from the nozzle tester.

Back Leakage Test

1. Connect the injector to the 5P4150 Nozzle Tester as shown earlier.

2. Pump the pressure to about 1030 kPa (150 psi) below the opening pressure. Release the handle and, with the pressure falling off naturally, note the time required for the pressure to drop from between 10 135 to 15 200 kPa (1470 to 2200 psi). If the nozzle is in good condition, the time will not be less than 6 seconds, or more than 45 seconds.

While a performance of the above test is done, look for any leakage from the lapped pressure faces of the nozzle holder and injector body. If leakage is visible or if the test takes less than 6 seconds, do not over tighten the nozzle cap in an effort to stop the leakage. Instead, remove the nozzle and inspect the pressure faces for foreign particles and surface for damage. Clean thoroughly and if the faces are in good condition, test again as in Steps 1 and 2.

If the pressure drop time is still less than 6 to 10 seconds, too much fuel is leaking around the nozzle needle stem. The nozzle and needle or injector must be replaced with a new assembly to correct the problem.

Nozzle And Seat Test

1. Connect the injector (nozzle tip dry) to the 5P4150 Nozzle Tester as shown earlier.

2. Pump the pressure to about 1030 kPa (150 psi) below the opening pressure. Drops of fuel must not collect or drip from the nozzle bottom face for at least 10 seconds. A light dampness is acceptable. If test results are not acceptable it may be possible to correct the problem by cleaning it. If not, a new assembly must be installed.

Spray Pattern Check

The pressure adjustment must be correct before checking the spray pattern.

Nozzle Spray Pattern Check (Typical Example)

1. Connect the injector to the 5P4150 Nozzle Tester as shown earlier.

2. Close the gauge protector valve and the on-off valve. Open the pump isolator valve.

3. Be sure the tip of the fuel injection nozzle is in the FT1384 Extension and the 8S2270 Fuel Collector.

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The spray fuel of an injector under pressure will puncture the skin. Keep hands away from the nozzle.

4. Make a rapid increase in pressure and look at the spray pattern when fluid begins to flow through the fuel injection nozzle. The spray must be the same through all four orifices. Any change, either vertically or horizontally, is an indication of a bad nozzle. See the different spray patterns in the illustration.

Fuel Injector Installation

Fuel Injector Washer And Seal Arrangement
(1) Rigid spacer. (2) Seal. (3) Copper washer.

1. Each time a fuel injector is removed from the cylinder head, replace copper washer (3) and dust seal (2).

2. Dust seal (2) should be positioned under spacer (1) and against the cylinder head.

3. Always install injectors with the return line fitting to the fuel injection pump side of the engine. The LRB top inlet injectors can be installed 180° out of position. In this position the nozzle holes will not spray fuel into the combustion chamber correctly. This will cause engine power loss and increased smoke.

Cooling System

These engines have a pressure type cooling system. A pressure type cooling system gives two advantages. The first advantage is that the cooling system can have safe operation at a temperature that is higher than the normal boiling (steam) point of water. The second advantage is this type of system prevents cavitation (the sudden making of low pressure bubbles in liquids by mechanical forces) in the water pump. With this type system, it is more difficult for an air or steam pocket to be made in the cooling system.

The reason an engine gets too hot is generally because regular inspections of the cooling system were not made. Make a visual inspection of the cooling system before tests are made.

Cooling System Visual Inspection

1. Check coolant level in the cooling system.

2. Look for leaks in the system.

3. Look for bent radiator fins. Be sure that air flow through the radiator does not have a restriction.

4. Inspect the drive belt for the fan.

5. Check for damage to the fan blades.

6. Look for air or combustion gas in the cooling system.

7. Inspect the pressure cap and the sealing surface for the cap. The sealing surface must be clean.

8. Look for large amounts of dirt in the radiator core and on the engine.

9. Loose or missing fan shrouds that cause poor air flow for cooling.

Cooling System Tests

Remember that temperature and pressure work together. When a diagnosis of a cooling system problem is made, temperature and pressure must both be checked. Cooling system pressure will have an effect on cooling system temperatures. For an example, look at the chart to see the effect of pressure and height above sea level on the boiling (steam) point of water.

Pressure Cap

Pressure Cap Schematic
(A) Seal.

One cause for a pressure loss in the cooling system can be a bad seal on the pressure cap of the system. Inspect the pressure cap carefully. Look for damage to seal (A) or the sealing surface. Any foreign material or deposits on the cap, seal or sealing surface must be removed.

To check the pressure cap for the pressure that makes the pressure cap open, use the following procedure:

1. Remove the pressure cap from the radiator.

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If the engine has been in operation and the coolant is hot, slowly loosen the pressure cap to the first stop and let the pressure out of the cooling system, then remove the pressure cap.

9S8140 Cooling System Pressurizing Pump Group

2. Put the pressure cap on 9S8140 Cooling System Pressurizing Pump Group.

3. Look at the gauge for the exact pressure that makes the pressure cap open. It must be 45 to 55 kPa (6.5 to 8.0 psi).

4. If the pressure cap is bad, install a new pressure cap.

Radiator And Cooling System Leak Check

To test the radiator and cooling system for leaks, use the following procedure.

1. Remove the pressure cap from the radiator.

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If the engine has been running and the coolant is hot, slowly loosen the pressure cap to the first stop and let the pressure out of the cooling system, then remove the pressure cap.

2. Make sure the radiator is full (hot) or nearly full (cold) of coolant.

3. Put the 9S8140 Cooling System Pressurizing Pump Group on the radiator.

4. Pump the pressure to 20 kPa (3 psi) more than the rated pressure of the cap.

5. Check the radiator for outside leakage.

6. Check all connections and hoses of the cooling system for outside leakage.

7. If no outside leakage is seen and the pressure reading on the gauge is still the same after 5 minutes, the radiator and cooling system do not have leakage. If the reading on the gauges goes down and no outside leakage is seen, there is leakage on the inside of the cooling system. Make repairs as necessary.

Water Temperature Regulator (Thermostat) Test

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A burn or personal injury will result if the water temperature regulator (thermostat), pan or the water is touched by hand during this test. Be sure either or all are cool before they are touched.

1. Remove the water temperature regulator (thermostat) from the engine.

2. Hang the regulator in a pan of water. Put a thermometer in the water. Put the regulator completely under water. Do not let the regulator make contact with the pan.

3. Put heat to the pan of water. Make the water in the pan move around. This keeps all of the water at the same temperature.

4. The regulator must open as follows:

Opening temperature ... 77 to 85°C (171 to 185°F)

Full open temperature ... 92 to 98°C (198 to 208°F)

5. Replace the regulator if the above temperatures are not correct.

Belt Adjustment

Belt Adjustment

Fan belt tension should be adjusted so there is 9.53 mm (.375 in) movement (deflection) under a force of 110 N (25 lb). The tension should be checked between the crankshaft and alternator pulleys and the crankshaft and air conditioner compressor (if equipped) pulleys.

Engine And Cooling System Heat Problem Checks

To check if there is a good reason for heat problems do the checks that follow:

1. What are the indications for the heat problems.

a. Temperature gauge is in the hot range and the temperature light is on.

b. Coolant boils out (comes out because of too much heat) of the cooling system during operations.

c. Coolant boils out on the floor when the engine is stopped.

d. Coolant must be added at the end of each day but Steps b and c are not present.

2. If indication in Step 1a is only present, it is possible the problem is only a damaged gauge, light or sender. Make a replacement of the damaged part.

3. If indication in Step 1b is present, do the procedure that follows:

a. Run the engine at medium idle (1200 rpm) for three minutes after high idle operation to cool off the hottest parts of the engine before it is stopped.

4. If indications in Step 1b, 1c, or 1d, are present, but Step 1a is not and the temperature gauge or light does work, the problem can be a damaged radiator cap seal or there can be a leak in the cooling system. Complete the procedure that follows:

a. Do the steps in Cooling System Visual Inspection, Cooling System Tests and Belt Adjustment in Testing and Adjusting of this module.

b. Clean the radiator with hot water (steam clean) at low water pressure and use detergent or air according to the different types of debris that caused the radiator to be dirty (plugged).

c. Check the engine high idle setting.

See High and Low Idle Speed Adjustments in Testing and Adjusting).

Another condition that can cause heat problems is the timing. Retarted (late) timing causes the engine to send more heat to the cooling system. Advanced (early) timing causes the engine to send less heat to the cooling system.

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NOTICE
If the timing is advanced too much, it will cause burnt exhaust valves and could cause damage to the exhaust manifold.

Cooling System Conditioner Recommendation

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The conditioner can cause damage to the eyes so take caution. Do not let it contact the skin. If contact is made, immediately wash the skin with soap and water. For the eyes, flush eyes with water for several minutes.

Caterpillar Cooling System Conditioner can be used with or without an ethylene glycol base antifreeze in the coolant. It is important to use the conditioner all through the year to prevent corrosion, cavitation and erosion in the cooling system. Use a .5 liters (1 pt) of conditioner for every 15 liters (4 gal) of coolant for the first 500 service hours. Then, and after every 500 additional hours or quarterly (whichever comes first) add .5 liters (1 pt) of conditioner for every 61 liters (16 gals) of existing conditioner/coolant mixture in the cooling system.

NOTE: Before first addition of conditioner to the coolant, the cooling system must be flushed and cleaned with chemicals if necessary.

Lubrication System

Lubrication System Problems

Any of the problems in the list below can be an indication of a problem in the engine lubrication system.

1. Too much oil consumption.

2. Low oil pressure.

3. High oil pressure.

4. Pressure relief valve setting.

5. Too much component wear.

Too Much Oil Consumption

Engine Outside Oil Leakage

Check for leakage at the seal at the rear main bearing. Also check for leakage at the seals at each end of the oil pan. Look for leakage at the gasket for the oil pan and at all lubrication system connections.

Combustion Area Oil Leakage

Oil leakage in the combustion area of the cylinders can be the cause of the blue smoke. There are three possible ways for oil leakage into the combustion area of the cylinders.

1. Oil leakage between worn valve bores or guides and valve stems.

2. Worn or damaged piston rings.

3. Compression rings not installed correctly.

Too much oil consumption can also be the result of the use of oil with the wrong viscosity. Oil with a thin (low) viscosity can be caused from dirt or fuel that gets in the crankcase, or by the engine that gets too hot.

Low Oil Pressure

Oil Pressure Light

If the oil light comes on, check for the causes that follow:

1. Low oil level in the crankcase.

2. Defective oil pressure light. Defective sender or restricted main oil gallery.

3. Restricted oil pump screen.

4. Leakage at the oil line connections.

5. Worn connecting rod or main bearings. Worn gears in the oil pump.

6. Oil pressure relief valve worn or it causes a restriction to the oil flow.

When the engine is running at normal temperature for operation and at high idle, the oil pressure is to be 205 to 415 kPa (30 to 60 psi).

A lower pressure indication is normal at low idle speeds. A 4C4890 Fittings Group can be used for a pressure check of the system.

High Oil Pressure

Oil pressure can be high if the spring for the oil pressure relief valve is not correct. The oil pressure will be high if the oil pressure relief valve cannot move from the closed position.

Too Much Component Wear

When some components of the engine show bearing wear in a short time, the cause can be a restriction in an oil passage. A broken oil passage can also be the cause.

If the oil pressure check shows the correct oil pressure, but a component is worn because it does not get enough lubrication, look at the passage for oil supply to that component. A restriction in a supply passage will not let enough lubrication get to a component and will cause early wear.

Pressure Relief Valve Setting

Oil Pressure Relief Valve
(1) Retaining cap. (2) Spring. (3) Plunger. (4) Body. (5) Cotter pin.

The relief valve for the oil pressure is a housing fastened to the bottom face of the cylinder block, inside the oil pan. Adjustment can be made to the oil pressure by installation of new spring (2). Check plunger (3) for wear. Replace if necessary.

To check and adjust the relief valve for the oil pressure, use the procedure that follows:

Oil Pressure Switch Location
(6) Switch.

1. Remove oil pressure switch (6) from the top of the oil filter head.

2. Install the 4000 kPa (600 psi) gauge from the 4C4890 Fittings Group in the hole from which switch (6) was removed.

3. Start the engine. Run the engine until it is at the normal temperature for operation.

4. Check the oil pressure with engine at low idle. The pressure should be 35 to 105 kPa (5 to 15 psi).

5. Raise the engine speed to high idle and check the oil pressure again. The pressure should be 205 to 415 kPa (30 to 60 psi).

6. If the oil pressure is not correct, the oil pump will have to be removed and tested.

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NOTICE
Do not put more than 415 kPa (60 psi) of air into the oil pump or the internal components could be damaged.

7. After removal of the oil pump, block the outlet port and put 345 to 415 kPa (50 to 60 psi) of air into the inlet port.

8. If the relief valve does not lift at 345 to 415 kPa (50 to 60 psi), the relief valve components will have to be replaced.

9. Remove cotter pin (5) from body (4), and remove cap (1), spring (2) and plunger (3).

10. Thoroughly clean all parts and inspect for wear or damage.

11. Install new spring (2) and necessary parts. Install valve assembly, oil pan and oil. Then do Steps 3 through 6 again.

12. If pressure is correct, remove the gauge, and install the oil pressure switch again.

Air Inlet And Exhaust System

Cylinder Compression

An engine that runs rough can have a leak at the valves or valves that need adjustment. Run the engine at the speed that gives rough running. To find a cylinder that has low compression or does not have good fuel ignition, loosen a pressure fuel line nut at the fuel injection pump or fuel injector. This will stop the flow of fuel to that cylinder. Do this for each cylinder until a loosened fuel line is found that makes not difference in engine rough running. Be sure to tighten each fuel line nut after the test before the next fuel line is loosened. This test can also be an indication that the fuel injection is wrong, so more checks of the cylinder will be necessary.

An analysis of the engine cylinder condition can be done with controlled pressure air through the cylinder head. Special Instruction GMG00694 explains the procedure.

1. Remove the fuel injector.

2. Adapt an air hose to 1P5564 Adapter. Install the 1P5564 Adapter in the fuel injector opening in the cylinder head.

3. Start crankshaft rotation by hand until the piston at the cylinder being inspected is at TC on the compression stroke. In this position, the valves of this cylinder will be against their seats.

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To prevent personal injury, do not turn the engine with the starting motor. Turn the key start switch OFF and disconnect the battery. Turn the crankshaft by hand, in direction of normal rotation.

4. Force the air into the cylinder and then check for air leakage. An air leak from the exhaust opening is an indication of exhaust valve leakage and an air leak from the air cleaner inlet is an indication of intake valve leakage. If there is air leakage in the crankcase during this test, the piston or piston rings can be the cause. The maximum leakage allowed is 205 kPa (30 psi). The oil pan can be removed to determine if there is air leakage in the crankcase during the test.

Valve Lash (Clearance) Adjustment

1. Do the procedure that follows to adjust valve clearance.

2. Remove the valve cover from the cylinder head.

Valve Location Schematic

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Always adjust valves with engine stopped to avoid personal injury. Turn the engine by hand and not by use of the starting motor. Disconnect the battery.

Valve Clearance Setting With Engine Stopped (Cold):

Intake ... 0.30 mm (.012 in)

Exhaust ... 0.30 mm (.012 in)

Timing Pointer Location
(1) Timing pointer. (2) Crankshaft pulley.

3. Turn the crankshaft in the direction of engine rotation until the No. 1 cylinder is at top center (TC) on the compression stroke. The engine will be at TC when the valves of the No. 4 cylinder are in the position of valve overlap (the period between the opening of inlet valve and closing of exhaust valve), and also when timing pointer (1) is lined up with the single timing mark on crankshaft pulley (2).

4. Measure the intake valve clearance for No. 1 and No. 2 cylinders and the exhaust valve clearance for No. 1 and No. 3 cylinders.

Valve Lash Adjustment Of No. 1 Exhaust

5. To adjust the valve clearance, loosen the locknut and turn the adjustment screw as needed to get the correct clearance. Then, hold the adjustment screw with a screwdriver and tighten the locknut. Check the valve clearance again.

6. Turn the crankshaft in the direction of engine rotation 360°.

Valve Lash Adjustment Of No. 4 Intake

7. Measure the intake valve clearance for No. 3 and No. 4 cylinders, and the exhaust valve clearance for No. 2 and No. 4 cylinders. Adjust when necessary, as explained in Step 5.

When the adjustment of the valve lash needs to be done several times in a short period of time, it can be an indication of wear in a different part of the engine. Find the problem and make necessary repairs to prevent more damage to the engine.

Not enough valve lash, if not corrected, can be the cause of rapid wear of the camshaft and tappets (valve lifters). Not enough valve lash can also be an indication of the seats for the valves being bad. Some reasons for the seats for the valves becoming bad are fuel injection nozzles with defects, restrictions to the inlet air or dirty air filters, wrong fuel setting or using the engine on loads that are too large for the engine.

Too much valve lash, if not corrected, can be the cause for broken valve stems or spring retainers. A fast increase in valve lash can be an indication of any of the items that follow:

a. Camshaft and tappets (valve lifters) worn.

b. Rocker arms worn.

c. Push rods that are bent.

d. Loose adjustment screw for the valve lash.

e. Broken socket on the upper end of a push rod.

If the camshaft and tappets (valve lifters) show signs of rapid wear, look for fuel in the lubrication oil or dirty lubrication oil as a possible cause when the necessary repairs are made.

Camshaft Lobe Measurement Procedure

Camshaft Lobe
(A) Lobe lift. (B) Lobe height. (C) Base circle.

To find lobe lift (A) of the camshaft, use the following procedure:

1. Measure lobe height (B) of one exhaust and one intake lobe.

2. Measure base circle (C) of one exhaust and one intake lobe.

3. Subtract base circle (C) dimension (Step 2) from lobe height (B) dimension (Step 1). The difference is actual lobe lift (A).

4. The specified (new) lobe lift (A) is 7.62 to 7.70 mm (.300 to .303 in).

5. The maximum permissible difference between actual lobe lift (Step 3) and specified lobe lift (Step 4) is 0.25 mm (.010 in)

Cylinder Head Check

Cylinder Head Check
(A) 8S6691 Cylinder Head Stand Set.

End to End Check
(1) Straight edge. (2) Feeler gauge.

Side to Side Check
(1) Straight edge. (2) Feeler gauge.

1. Remove the cylinder head from the engine and put it on 8S6691 Cylinder Head Stand Set (A).

2. Clean the cylinder head thoroughly. Make sure the contact surfaces of the cylinder head and cylinder block are clean, smooth and flat.

3. To check the cylinder head for being flat, use a straight edge (1) and feeler gauge (2).

4. Check the cylinder head from end to end and then side to side.

5. The cylinder head must not be out of flat more than 0.08 mm (.003 in) for the total width. The maximum permissible out of flat for the total length is 0.15 mm (.006 in). The out of flat condition must be gradual from end to end and side to side.

Skimming The Cylinder Head

If the cylinder head face is out of flat more than the limits shown, or if it is damaged, the head can be skimmed (material removed from the face).

The maximum amount the head can be skimmed is 0.30 mm (.012 in) as long as the injector does not project beyond the face of the cylinder head more than 4.45 mm (.175 in).

Valve Depth Check

1. Use 8T0455 Liner Projection Tool Group to check intake and exhaust valve depth below the cylinder head face.

Liner Projection Tool
(1) 1P2402 Gauge Body. (2) 1P2403 Dial Indicator. (3) 1P5507 Gauge.

2. Use gauge (3) to zero dial indicator (2).

Valve Depth Check
(1) 1P2420 Gauge Body. (2) 1P2403 Dial indicator.

3. Use body (1) and dial indicator (2) assembly to check intake and exhaust valve depth below the cylinder head face. The indication should be as follows:

Intake:

Minimum ... 0.89 mm (.035 in)

Maximum ... 1.14 mm (.045 in)

Exhaust:

Minimum ... 1.19 mm (.047 in)

Maximum ... 1.45 mm (.057 in)

4. The above limits are production limits. If the valve depth below the cylinder head face on a used engine is more than the maximum figures that follow, the valves, exhaust valve seats and possibly the cylinder head will have to be replaced.

Intake (Wear Limit):

Maximum ... 1.55 mm (.061 in)

Exhaust (Wear Limit):

Maximum ... 1.85 mm (.073 in)

Basic Block

Cylinder Liner Projection

NOTE: New cylinder blocks and liners have been introduced. See Cylinder Block in Specifications for the differences between earlier and current engines.

The liners in these engines are flanged. Earlier production thin wall liners are a 0.05 to 0.10 mm (.002 to .004 in), and current production thick wall liners are 0.03 to 0.08 mm (.001 to .003 in) interference fit in the block. They are also bored and finished to a diameter of 98.48 to 98.50 mm (3.877 to 3.878 in).

The maximum permissible worn inside diameter for production or service liners is 98.70 mm (3.886 in). The liners cannot be bored oversize.

For service, a prefinished liner is available having a transition fit of ± 0.03 mm (± .001 in) in the block (for all engines). The inside diameter is also 98.48 to 98.50 mm (3.877 to 3.878 in). Check liner projection above the block as follows:

1. Use the 8T0455 Liner Projection Tool Group to measure liner (flange) projection. Special Instruction Form No. SMHS7727 is with the tool.

Liner Projection Tool
(1) 1P2402 Gauge Body. (2) 1P2403 Dial Indicator. (3) 1P5507 Gauge.

2. Use gauge (3) to zero the dial indication (2) as shown.

Liner Projection Check
(1) 1P2402 Gauge Body. (2) 1P2403 Dial Indicator.

3. Use body (1) and dial indicator (2) assembly to measure the cylinder liner (flange) projection in four locations around the liner. Do not measure projection from the flame ring (if equipped). Projection must be 0.10 mm (.004 in) above to 0.10 mm (.004 in) below the cylinder block face. The four measurements should not vary more than 0.03 mm (.001 in). The average projection between adjacent cylinders must not vary more than 0.03 mm (.001 in).

Connecting Rods And Pistons

1. Put a liberal amount of clean engine oil on the crankshaft journals, main bearings and thrust washers. Put the upper half of the main bearings and the crankshaft in position in the cylinder block.

2. Slide the upper thrust washer halves into the recesses provided on either side of the center main bearing housing.

3. Install the lower half of the main bearings into the main bearing caps. Install the main bearing caps to their respective positions. Position the lower thrust washer halves on either side of the center main bearing cap.

4. The main bearing caps are numbered 1 through 5, beginning at the front of the block. Each cap is also marked with a serial number which is also stamped on the cylinder block bottom face. They all should read the same way.

5. Install and tighten the main bearing bolts and tighten them to a torque of 247 N·m (180 lb ft).

Use the 1U6684 Piston Ring Compressor to remove or install piston rings.

6. Put a liberal amount of clean engine oil in the bore of each cylinder and on the pistons before they are installed.

7. Install the piston and connecting rod assemblies using the piston ring compressor as a guide. Be sure the piston and rod number are the same as for the cylinder bore each is installed in. The rod identification number must be opposite the camshaft. The word "Front" or arrow marked on the piston crown must be toward the front of the engine. If the piston crown is not marked, put the offset (narrowest distance between hole and edge of piston) of the piston toward the fuel injection pump side of the block.

The connecting rod bearings must fit tightly in the bore of the rod. If bearing joints or backs are worn (fretted), check for bore size as this is an indication of wear because of looseness. Install the bearing cap with the numbers on the same side of the rod and cap.

8. Install the connecting rod bolts so the flat on the bolt head is against the shoulder of the rod. Install new rod nuts. Tighten rod nuts to the torque that follows:

Cadmium plated nuts (silver color) ... 100 N·m (75 lb ft)

Phosphated nuts (dull black color) ... 130 N·m (95 lb ft)

9. Check the piston height with the 8T0455 Liner Projection Tool Group.

Liner Projection Tool
(1) 1P2402 Gauge Body. (2) 1P2403 Dial Indicator. (3) 1P5507 Gauge.

Piston Height Check
(1) 1P2402 Gauge Body. (2) 1P2403 Dial Indicator.

10. Use gauge (3) to zero dial indicator (2) as shown.

11. Use body (1) and dial indicator (2) assembly to make a measurement of piston height. Check the piston height in four locations around the piston. The piston height must be 0.28 to 0.48 mm (.011 to .019 in) for the 4.236 engines or 0.36 to 0.58 mm (.014 to .023 in) for the C4.236 engines.

Crankshaft Rear Seal Installation

The crankshaft rear seal has a dust lip that protrudes from the rear face of the seal which can be damaged by using a regular seal driver. The 6V2186 Seal Driver can be reworked as shown in the following drawing to prevent damaging the dust lip.

Modified 6V2186 Seal Driver

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NOTICE
The seal is easily damaged and extreme care should be taken when handling and installing it. Any visual damage across the lip of the seal will cause leakage of the seal.

Crankshaft Rear Seal
(A) 2.3 mm (.09 in) position. (B) 4.6 mm (.18 in) position. (C) 6.9 mm (.27 in) position.

1. On production engines the seal is at position (A), 2.3 mm (.09 in) from the face of the rear housing. If the seal leaks oil, use the modified seal driver shown above and move the seal to position (B), 4.6 mm (.18 in) from the rear housing face.

2. If the seal is at position (B) and is leaking, use the modified seal driver to move the seal to position (C), 6.9 mm (.27 in) from the rear housing face.

3. If all three seal positions have been used and the seal is leaking, the sealing area of the crankshaft flange can be reground to a minimum diameter of 133.17 mm (5.243 in). Leave an unmachined diameter a distance of 4.78 mm (.188 in) from the rear end of the crankshaft. If a crankshaft is reground, it must be rehardened after the grinding operation.

Crankshaft Rear Seal Surface

Flywheel

Heat the ring gear to install it. Do not heat to more than 246°C (475°F). Install the ring gear so the chamber on the gear teeth is next to the starting motor pinion when the flywheel is installed.

Flywheel Checks

Face Runout Check

Flywheel Face Runout Check

1. Install the dial indicator as shown. Force the crankshaft to the rear to remove the main bearing clearance before the measurement is taken at each point.

2. Set the dial indicator at 0.0 mm (.00 in).

3. Turn the flywheel and read the indicator every 90°.

4. The difference between the lower and higher measurements taken at all four points must not be more than 0.20 mm (.008 in), which is the maximum permissible face runout of the flywheel.

Outside Diameter Check

Flywheel Outside Diameter Runout Check

1. Install the dial indicator at the top dead center of the flywheel as shown. Mount the dial indicator to the engine block.

2. Set the dial indicator at 0.0 mm (.00 in).

3. Turn the flywheel and read the indicator every 90°.

4. The difference between the lower and higher measurements taken at all four points must not be more than 0.30 mm (.012 in), which is the maximum permissible outside diameter runout of the flywheel.

Electrical System

Battery

Reference: Refer to Special Instruction Form No. SEHS8268 for the use of the battery load tester with the use of the other above tools.

6V4930 Battery Load Tester

The battery circuit is an electrical load on the charging unit. The load is variable because of the condition of the charge in the battery. Damage to the charging unit will result, if the connections, (either positive or negative) between the battery and charging unit are broken while the charging unit is charging. This is because the battery load is lost and there is an increase in charging voltage.

High voltage will damage, not only the charging unit but also the regulator and other electrical components.

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NOTICE
To prevent damage to the charging circuit components, never disconnect any charging unit circuit or battery circuit cable from the battery while the charging unit is in operation.

Load test a battery that does not hold a charge when in use. To do this, put a resistance across the battery main connections (terminals). Refer to Special Instruction, Form No. SEHS7633 for the complete battery test procedure.

Starting Motor

For detailed Testing & Adjusting and Disassembly & Assembly information refer to the Bosch JF Series Starting Motors Module, Form No. SENR3550.

On Machine Starting Motor Diagnosis Procedure

The following simplified procedure is intended to help the serviceman determine if a starting motor needs to be removed and replaced or repaired. It is not intended to cover all possible problems and conditions, but to serve only as a guide. The most common 12 volt circuit is shown and discussed.

Typical 12 Volt Starting Circuit
(1) Test point. (2) Test point. (3) Test Point. (4) Test Point. (5) Test Point. (X) Hold-in coil. (W) Pull-in coil.

General Information

All starting systems are made up of four elements. They are the ignition switch, start relay, the starting motor solenoid and starting motor. The only exception to this is that on some small engines the start relay may not be required. In this case, the start switch powers the starting motor solenoid directly.

Start switches are relatively low current devices. They are rated to switch approximately 5 to 20 amps. Because the coil of a start relay [between test point (1) and (2)] draws about 1 amp, the start switch can easily turn on the start relay and have long life.

The switch contacts of a typical start relay are rated to switch between 100 and 300 amps. Because the solenoid requires 5 to 50 amps, the start relay can easily switch this load.

The starting motor solenoid has two functions: 1) it engages the pinion with the flywheel, and 2) it is a high current switch rated about 1000 amps that actually turns on the starting motor.

The starting motor solenoid has two coils. Pull-in coil (W) draws about 40 amps and hold-in coil (X) requires about 5 amps. The instant the start relay closes, both coils (W) and (X) receive power. Battery voltage is applied to the high end of both coils, at test point (3) which is the start (S) terminal. The low end of hold-in coil (X) is permanently grounded to the ground post or motor housing of the starting motor. Grounding for the low end, test point (4), of pull-in coil (W) is momentary, and takes place through the DC resistance of the starting motor. As soon as magnetic force builds in both coils, the pinion moves toward the flywheel ring gear. The pinion will stop short of engagement of the flywheel ring gear. Only then will the solenoid contacts close to power the starting motor. This temporarily removes the ground from pull-in coil (W), and puts battery voltage on both ends of it while the starting motor cranks. During this period, the pull-in coil is out of the circuit. Cranking continues until power to the solenoid is broken by releasing the ignition switch.

The result of these switches and relays is to permit a 5 amp dash-mounted switch to turn on a 500 to 1000 amp motor used to crank an engine.

Battery voltage (power) available during cranking varies according to the temperature of the batteries. The following chart is a guide as to what to expect from a normal system.

The next chart shows maximum acceptable voltage loss in the high current battery circuit feeding the starting motor. These values are maximums for machines of approximately 2000 SMH and up. Newer machines would be less than those shown.

Voltages greater than those shown are most often caused by loose and/or corroded connections or defective switch contacts.

Diagnosis Procedure

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NOTICE
Do not operate the starting motor for more than 30 seconds at a time. After 30 seconds, the cranking must be stopped for two minutes to allow the starting motor to cool. This will prevent damage to the starting motor due to excessive heat buildup.

If the starting motor cranks real slow or does not crank at all, do the following procedure:

1. Measure battery voltage at the battery posts with the multimeter while cranking or attempting to crank the engine. Make sure to measure the battery posts. Do not measure the cable post clamps.

2. Is battery voltage equal to or greater than shown in Figure 1?

a. If the battery voltage is OK, go to Step 3.

b. If the battery voltage is too low, test the battery as shown in Special Instruction Form No. SEHS7633.

NOTE: A low battery can be caused by battery condition or a shorted starting motor.

3. Measure current draw on the (+) battery cable between the battery and the starting motor solenoid with the clamp-on ammeter. The maximum current draw allowed is shown in Specifications under Load Test. The figures shown in Specifications are taken at temperature of 27°C (80°F). At temperatures below 27°C (80°F), the voltage will be less and the current draw will be higher. If current draw is too much, the starting motor has a problem and must be removed for repair or replacement.

NOTE: If voltage at the battery post is within approximately 2 volts of the lowest value in the applicable temperature range of Figure 1 and if the large starting motor cables get hot, then the starting motor has a problem and the 8T0900 Ammeter test is not needed.

4. Measure starting motor voltage from test point (4) to (5) with the multimeter while cranking or attempting to crank the engine.

5. Is voltage equal to or greater than shown in Figure 1?

a. If the starting motor voltage is OK, the battery and starting motor cables down to the motor are within specifications. Go to Step 8.

b. If the starting motor voltage is low, the voltage drop between the battery and the starting motor is too great. Go to Step 6.

6. Measure the voltage drops in the cranking circuits with the multimeter. Compare the results with maximum voltage drops allowed in Figure 2.

7. Are all the voltages within specifications?

a. If the voltage drops are OK, go to Step 8, to check the engine.

b. If the voltage drops are too high, repair and/or replace the faulty electrical component.

8. Rotate the crankshaft by hand to make sure it is not locked up. Check oil viscosity and any external loads that would affect engine rotation.

9. Is the engine locked up or hard to turn?

a. If it is, repair the engine as required.

b. If the engine is not hard to turn, go to Step 10.

10. Does the starting motor crank?

a. If it does crank, remove the starting motor for repair and/or replacement.

b. If it does not crank, check for blocked engagement of the pinion and flywheel ring gear.

NOTE: Blocked engagement and open solenoid contacts will give the same electrical symptoms.

For off machine and internal component tests of the starting motor, refer to the Bosch JF Series Starting Motors Module, Form No. SENR3550.

Alternator

For detailed Testing & Adjusting and Disassembly & Assembly information refer to the Bosch K1/N1 Series Alternators Module, Form No. SENR3685.

On Machine Alternator Output Test

1. Put the multimeter positive (+) lead on the Bat terminal of the alternator. Put the negative (-) lead on the ground terminal or the frame of the alternator. Put the clamp-on ammeter around the positive output wire of the alternator.

2. Turn off all electrical accessories. With the fuel off, crank the engine for 30 seconds. Wait two minutes to let the starting motor cool. If the system appears to be up to specifications, crank the engine again for 30 seconds.

NOTE: Cranking the engine for 30 seconds partially discharges the batteries in order to do a charging test. If the battery is already low in charge, skip this step. Jump-start engine or charge as required.

3. Start the engine and run at full throttle.

4. Immediately check output current. This initial charging current should be equal to or greater than the full output current of 55A.

5. Within approximately 10 minutes at full throttle (possibly longer, depending upon battery size, condition and alternator rating), the alternator output voltage should be 14.0 ± 0.5V to indicate the alternator is performing within specification. See the Fault Conditions And Possible Causes Chart.

6. The charging current during this period should taper off to less than approximately 10 Amps, depending again upon battery and alternator capacities. See the Fault Conditions And Possible Causes Chart.

7T2876 Alternator Charging Circuit

7. The K1/N1 alternators are self-excited at high speeds. For this reason, they are turned on by the battery, through the key start switch, to start the charging process at low speed. They are turned on any time the key start switch is either in the ON or START position. If there is low or no alternator output, check the circuit between the key start switch and the alternator for an open. Also check the resistor and diode (if equipped). The resistance of the resistor should be 22 ± 4 Ohms.

8. If a machine is jump started because the battery is too low, the alternator may not have any output. This is because the battery may be too low to send current to the alternator. The alternator needs current to start the charging process.