3208 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. To remove the air from the fuel system, open the manual bleed valve on the fuel injection pump housing. Operate the priming pump until the flow of fuel from the manual bleed valve is free of air. Close the manual bleed valve and fasten the fuel priming pump. 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 cylinder heads, and permit the fuel to come out until it is free of air. Tighten the fuel line nuts. If air is not removed in this way, put 5 psi (35 kPa) [CAUTION do not use more than 8 psi (55 kPa)] of air pressure to the fuel tank and check for leaks at connections between the fuel tank and the fuel transfer pump. If there are no leaks at the connections, 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 as per the Operation Guide (SEBU5216). 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.

4. Low Fuel Pressure - If the constant bleed valve stays open it can cause the fuel pressure to be too low for the engine to start.

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 adjustment is .015 in. (0.38 mm) and exhaust valve adjustment is .025 in. (0.64 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 the chart Misfiring and Running Rough.

Exhaust Smoke Can Not Be Seen While Starting

9. 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.

10. No Fuel From Fuel Injection Pump - Open the manual bleed valve on the fuel injection pump housing. 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, follow Steps (a) through (d) until the problem is corrected.

a. Prime fuel system as per Operation Guide (SEBU5216).

b. Check shut-off 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. If the solenoid does not work, install a new solenoid.

c. At temperatures below 10° F (-12° C) and if you are not using a good quality fuel, 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.

d. Check for fuel supply line restriction by removing the fuel supply line from the fuel filter base. Put 5 psi (35 kPa) [CAUTION do not use more than 8 psi (55 kPa)] 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.

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

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