1100 SERIES DIESEL TRUCK ENGINE Difficult Starting Caterpillar


Difficult Starting
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1.1. Crankshaft Turns Free Exhaust Smoke Can Be Seen While Starting
2.1. Exhaust Smoke Cannot Be Seen While Starting
3.1. Crankshaft Will Not Turn
4.1. Crankshaft Turns Too Slowly

Crankshaft Turns Free Exhaust Smoke Can Be Seen While Starting

Cold Outside Temperatures ... It may be necessary to use starting aids, or warm engine oil or coolant, at temperatures below 10°F (-12°C).

Air in Fuel System ... See PRIMING THE FUEL SYSTEM.

Low Quality Fuel ... Drain a small amount of fuel from the tank and check for water in the fuel. If there is water in the fuel, drain the tank and fill with a good quality fuel. Change the fuel filter and "prime". If there is no water in the fuel, using an outside supply of fuel, prime and start the engine. If engine starts correctly using different fuel, remove all fuel from the tank and fill with good quality fuel and prime the fuel system.

Fuel Injection Timing Not Correct. *

Valve Adjustment Not Correct ... Check and make necessary adjustment. See VALVE LASH ADJUSTMENT.

Defective Fuel Nozzle(s) ... Replace the fuel nozzles.

Low Compression ... See the topic MISFIRING AND RUNNING ROUGH.

Exhaust Smoke Cannot Be Seen While Starting

No Fuel in Tank ... 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.

No Fuel From Fuel Injection Pump ... Loosen one or more of the fuel injection line nuts at the cylinder heads. With ignition switch on 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, see the following information.

Prime fuel system.

Check solenoid by turning on ignition switch. You must hear a sound when the plunger opens. If no sound is heard, make sure there is battery voltage at the solenoid and that the voltage is no less than 8 volts (terminal voltage while cranking). If voltage is less than 8 volts, the problem is low charge in battery or defective wiring. If voltage is 8 or more volts, loosen the cap on the tee at the fuel filter and release the fuel pressure at the solenoid. If the solenoid now works, the fuel transfer pump is holding fuel pressure at the solenoid. Clean or install a new fuel transfer pump. If solenoid does not work when pressure is released, install a new solenoid.

Check for a dirty fuel filter by checking fuel pressure at the fuel filter outlet while turning the engine with the starter. If fuel pressure is less than 13 psi (0,9 kg/cm2) check fuel pressure at the outlet of the fuel transfer pump. If fuel pressure at the outlet of the transfer pump is more than the fuel pressure at the fuel filter outlet, install a new fuel filter.

Check for a defective fuel transfer pump by checking fuel pressure at the outlet of the fuel transfer pump while turning the engine with the starter. If fuel pressure is less than 13 psi (0,9 kg/cm2), clean the primary fuel filter (if truck is so equipped). If fuel pressure is still low, connect a vacuum gauge to the inlet side of the fuel transfer pump and turn the engine with the starter. If the inlet vacuum is less than 9 inches (228,6 mm) of mercury, install a new fuel transfer pump. If the inlet vacuum is more than 9 inches (228,6 mm) of mercury, there is a restriction in the fuel supply line and/or the fuel tank.

Check for fuel supply line restriction by removing the fuel supply line from the fuel transfer pump. Put 5 psi (0,35 kg/cm2) [CAUTION: Do not use more than 8 psi (0,56 kg/cm2)] of air pressure to the fuel tank. 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.

No Air to Engine ... Loosen the air inlet at the engine. If engine will start, check air inlet system for damage and/or restrictions.

Exhaust System Not Open ... Loosen the exhaust pipes from the exhaust manifolds. If engine will start, check the exhaust system for damage and/or restrictions.

Crankshaft Will Not Turn

Low or No Battery Voltage...Check battery voltage. If battery voltage is less than 8 volts (terminal voltage while cranking) put a charge to the battery. If battery will not hold a charge, install a new battery.

Defective Switch, Wiring or Connection in Switch Circuit ... With starter 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, starter switch, and magnetic switch (if used).

Defective Cable or Connection; Battery to Starter ... With starter 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 defective cable or connection between the battery and the starter.

Defective Starter Solenoid ... Remove and repair a solenoid which does not work when voltage is correct at both the battery and starter switch connections.

Defective Starting Motor ... If the solenoid works and the starting motor does not turn the crankshaft, the starting motor is defective. Before removing the starting 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 starting motor again. If the starting motor still will not work, remove the starting motor and repair or install a new starting motor.

Transmission or Power Take-off Problem Prevents Crankshaft From Turning ... If the crankshaft can not be turned by hand, disconnect the transmission and power take-off. If crankshaft will now turn, find cause of the problem in the transmission or power take-off and make necessary corrections.

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, wrong pistons installed in the engine, and valves making contact with pistons. *

Crankshaft Turns Too Slowly

Low Battery Voltage ... Check battery voltage. If battery voltage is less than 8 volts (terminal voltage while cranking), put a charge to the battery. If battery will not hold a charge, install a new battery.

Defective Cable or Connection; Battery to Starter ... With switch in START position, check voltage at battery cable connection to starter. If voltage is less than 8 volts (terminal voltage while cranking) check the cables and connections.

Oil Too Thick For Free Crankshaft Rotation ... Use SAE 10W/30, 10W/40, or SAE 30 grade oils for temperatures above 32°F (0°C). Use SAE 10W, 10W/30, or 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.

Defective Starting Motor ... Remove and test. Make repairs as necessary or install a new starting motor.

Extra Outside Loads ...Damage to the power take-off equipment 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.

Mechanical Problem Inside Engine ... Take the engine apart and check all components for damage. *


*Authorized dealers are equipped with the necessary tools and personnel familiar with disassembly and assembly procedures to perform these services.