3406 DIESEL TRUCK ENGINE Caterpillar


Difficult Starting

Usage:



Engine Crankshaft Turns Freely

Exhaust Smoke Can Be Seen While Starting Recommended Procedure

1. Cold Outside Temperatures ... It can be necessary to use starting aids, or to heat engine oil or coolant at temperatures below 10°F (-12°C).
2. Air in Fuel System ... With air in the fuel system, the engine will normally be difficult to start, run rough, and release a large amount of white smoke. If the engine will not start, loosen a fuel injection line nut at the valve cover base. With the governor lever in the shutoff position, operate the fuel priming pump until the flow of fuel from the loosened fuel injection line is free of air. Tighten the fuel line nut. Fasten the priming pump and start the engine. If the engine still does not run smooth or releases a large amount of white smoke, loosen the fuel line nuts one at a time at the valve cover base until the fuel that comes out is free of air. Tighten the fuel line nuts. If the air can not be removed in this way, put 5 psi (35 kPa) of air pressure to the fuel tank.


NOTICE

Do not use more than 8 psi (55 kPa) of air pressure in the fuel tank or damage to the tank may result.


Check for leakage at the connections between the fuel tank and the fuel transfer pump. If leaks are found, tighten the connections or replace the lines. If there are no visual leaks, remove the fuel supply line from the tank and connect it to an outside fuel supply. If this corrects the problem, the suction line (standpipe) inside the fuel tank has a leak.

3. Low Quality Fuel ... Remove a small amount of fuel from the tank and check for water in the fuel. If there is water in the fuel, remove fuel from the tank until it is free of water and fill with a good quality fuel. Change the fuel filter and "prime" (remove the air and/or low quality fuel from the fuel system) the fuel system with the fuel priming pump. If there is no water in the fuel, prime and start the engine by using an outside source of fuel. If engine starts correctly using different fuel, remove all fuel from the tank and fill with good quality fuel. Prime the fuel system if necessary.
4. Low Fuel Pressure ... Change the fuel filter. If the pressure is still low, check the bypass valve in the fuel transfer pump. Debris in the system can make the valve become stationary in the open position.
5. Fuel Injection Timing Not Correct ... Check and make necessary adjustments as per Testing and Adjusting section of this Service Manual.
6. Valve Adjustment Not Correct ... Check and make necessary adjustments as per Testing and Adjusting section of this Service Manual. Intake valve clearance is .015 in. (0.38 mm) and exhaust valve clearance is .030 in. (0.76 mm).
7. Bad Fuel Nozzle(s) ... Remove the fuel nozzles and test as per Testing and Adjusting section of this Service Manual.
8. Low Compression ... See Misfiring and Running Rough.

Exhaust Smoke Can Not Be Seen While Starting

9. No Fuel in Tank(s) ... Check fuel level visually (do not use the fuel gauge only). Be sure tank selection valve is open to the tank with fuel in it. Be sure valve in fuel line between the tanks is open.
10. No Fuel From Fuel Injection Pump ... Loosen a fuel injection line nut at the camshaft base. With ignition switch in the ON position and accelerator in the FUEL ON position, turn the engine with the starter to be sure there is no fuel from the fuel injection pump. To find the cause for no fuel, follow Steps (a) through (d) until the problem is corrected.

a. Prime the fuel system as shown in Procedure No. 2.

b. Check the shut-off solenoid. Remove the cover on the governor and check the plunger. The plunger should be fully extended to allow full rack travel. If rack travel is restricted, adjust the plunger or replace the solenoid.

c. If you are not using a good quality of fuel at temperatures below 10°F (- 12°C), it is possible that the fuel in the system can "wax" (not have correct flow characteristics) and cause a restriction in the fuel system. Install a new fuel filter. It may be necessary to drain the complete fuel system and replace with a No. 1 grade of fuel.

d. Check for fuel supply line restriction by removing the fuel supply line for the fuel filter base. Put 5 psi (35 kPa) of air pressure to the fuel tank.


NOTICE

Do not use more than 8 psi (55 kPa) of air pressure in the fuel tank or damage to the tank may result.


If there is no fuel, or only a weak flow of fuel from the fuel supply line, there is a restriction in the fuel supply line and/or the fuel tank.

11. Exhaust System Not Open ... Loosen the exhaust pipe from the exhaust manifold. If engine will now start, check the exhaust system for damage and/or restrictions.

Engine Crankshaft Will Not Turn Recommended Procedure

1. Low or No Battery Voltage ... Check battery voltage. If battery voltage is less than 8 volts for a 12 volt system, or 16 volts for a 24 volt system, put a charge to the battery. If battery will not hold a charge, load test the battery as shown in the ELECTRICAL SYSTEM of the Testing and Adjusting section of this Service Manual.
2. Bad Switch, Bad Wiring or Connection in Switch Circuit ... With ignition switch in START position, check voltage at switch connection on starter solenoid. If there is no voltage, or if the voltage is low at this connection, check wiring, connections, ignition switch, and magnetic switch (if used).
3. Bad Cable or Connection; Battery to Starter ... With ignition switch in the START position, check voltage at connection of battery cable to starter. If there is no voltage, or if the voltage is low at this connection and there is good voltage at the battery, check for bad cable or connection between the battery and the starter.
4. Bad Starter Solenoid ... Remove and repair a solenoid which does not work when voltage is correct at both the battery and ignition switch connections.
5. Bad Starter Motor ... If the solenoid works and the starter motor does not turn the crankshaft, the starter motor is bad. Before removing the starter motor, turn the crankshaft by hand to be sure a mechanical failure inside the engine, transmission, or power take-off is not preventing the crankshaft from turning. If crankshaft turns freely by hand, engage the starter motor again. If the starter motor still will not work, remove the starter motor and repair it, or install a new starter motor.
6. Transmission or Power Take-off (if so equipped) Problem Prevents Crankshaft From Turning ... If crankshaft can not be turned by hand, disconnect the transmission and power take-off. If crankshaft will now turn, find the cause of the problem in the transmission or power take-off and make necessary corrections.
7. Inside Problem Prevents Engine Crankshaft From Turning ... If the crankshaft can not be turned after disconnecting the transmission and power take-off, remove the fuel nozzles and check for fluid in the cylinders while turning the crankshaft. If fluid in the cylinders is not the problem, the engine must be disassembled to check for other inside problems. Some of these inside problems are bearing seizure, piston seizure, and valves making contact with pistons.

Engine Crankshaft Turns Too Slowly

8. Low Battery Voltage ... Check battery voltage. If battery voltage is less than 8 volts for a 12 volt system, or 16 volts for a 24 volt system, put a charge to the battery. If the battery will not hold a charge, load test the battery as shown in the ELECTRICAL SYSTEM of the Testing and Adjusting section of this Service Manual.
9. Bad Cable or Connection; Battery to Starter ... With switch in START position, check voltage at battery cable connection to starter. If voltage is low at this connection and there is good voltae at the battery, check for bad cable or connection between the battery and the starter.
10. Oil Too Thick for Free Crankshaft Rotation ... Use SAE 10W/30, 10W/40 grade oils for temperatures below 32°F (0°C). At temperatures below -10°F (-23°C) it may be necessary to warm the oil for free crankshaft rotation.
11. Bad Starter Motor ... Remove and test. Make repairs as necessary or install a new starter motor.
12. Extra Outside Loads ... Damage to the power take-off equipment (if so equipped) and/or transmission can put extra load on the engine. This prevents free rotation of the crankshaft. To check, disconnect the transmission and power take-off, and start the engine.
13. Mechanical Problem Inside Engine ... Take the engine apart and check all components for damage.
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