3412E and C30 Marine Engines Caterpillar

Either too much fuel for combustion or not enough fuel for combustion can be the cause of a problem in the fuel system. The source of the problem is difficult to find.

When noticeable smoke rises from the exhaust, the problem can be caused by the following reasons:

• a defective unit injector

• not enough air for good combustion

• an overload at high altitude

• oil leakage into combustion chamber

• altitude

• air inlet and exhaust leaks

Note: Refer to Troubleshooting for more information on the fuel system.

Fuel System Inspection

A problem with the components that send fuel to the engine can cause low fuel pressure. This can decrease engine performance.

Illustration 1	g00550906
(1) Electronic Control Module (ECM). (2) Fuel filter. (3) The fuel gallery that is located within the fluid manifold. (4) Fuel tank. (5) Fuel transfer pump. (6) Fuel pressure regulating valve.

1. Check the fuel level in the fuel tank. Inspect the cap for the fuel tank. Make sure that the vent is not filled with dirt.

2. Clean the screen that is inside the inlet fitting of the fuel transfer pump.

3. Install a new fuel filter. Clean the primary fuel filter.

4. Remove any air that may be in the fuel system.

   If there is air in the fuel system, use the priming pump to open the drain valve on the fuel injection pump housing. Drain the fuel system until fuel without air flows from the drain line.

Checking Engine Cylinders Separately

Low temperature at an exhaust manifold port is an indication of no fuel to the cylinder. This can possibly be an indication of an injector with a defect. An extra high temperature at an exhaust manifold port can be an indication of too much fuel to the cylinder. High temperatures may also be caused by an injector with a defect.

Refer to Testing And Adjusting, "Measurement of Exhaust Temperature" for the procedure for checking the temperatures in the exhaust manifold port.

Start Up Procedure

Note: Refer to Operation and Maintenance Manual, "Engine Starting" in the Operation Section.

If the fuel system has been worked on, use this starting procedure to start the engine:

1. Disconnect the air inlet system from the turbocharger.

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Be careful when placing the steel plate against the opening on the turbocharger air inlet. To avoid crushed fingers, do not position fingers between the steel plate and the opening on the turbocharger air inlet. Due to excessive suction, the plate can be forcefully pulled against the opening on the turbocharger air inlet.

2. Another person will need to help as a precautionary step. This person should be ready to use the steel plate to cover the turbocharger air inlet if a problem occurs.

   Note: Make sure that the steel plate is large enough to cover the entire turbocharger air inlet.

3. Start the engine.

   Immediately place the steel plate against the opening on the turbocharger air inlet if the engine operates in one of the following ways:

   • The engine runs too fast.

   • The engine runs out of control.

   Covering the opening will stop the air supply to the engine. This will cause the engine to stop.

Fuel Pressure

Table 1

Tools Needed
Part Number	Part Name	Quantity
1U-5470	Engine Pressure Group	1
3Y-2888	Connector	1
3J-1907	O-Ring Seal	1

Note: Both the 5P-2720 Probe Adapter and the 5P-2718 Pressure Probe can be used with these tools. Use these additional tools to allow the future installation of pressure probes.

The 1U-5470 Engine Pressure Group can be used in order to check the engine's fuel pressures.

Illustration 2	g00284796
1U-5470 Engine Pressure Group (1) Pressure indicators. (2) Zero adjustment screw. (3) Pressure indicator. (4) Pressure tap. (5) Pressure indicator.

This tool group has a gauge that is used to register the pressure in the fuel manifolds. The Special Instruction, SEHS8907 is with the tool group.

During normal operating conditions and during load conditions, the fuel pressure should register within the following range:

• 310 to 415 kPa (45 to 60 psi)

Fuel pressure to the fluid manifold should be as above, minus the delta P across the secondary fuel filter.

The pressure drop across the secondary fuel filter is typically at least 35 kPa (5 psi) with a new filter. The pressure differential will increase as the filter accumulates deposits. If fuel pressure in the fuel gallery within the fluid manifold at the injectors decreases to approximately 69 kPa (10 psi), misfiring may occur.

A check valve is mounted at the junction of the fuel lines. These fuel lines are located at the rear end of the fuel gallery that is located within the fluid manifold. The valve maintains fuel pressure at low engine speeds. The spring loaded check valve prevents the fuel from draining from the head after engine shutdown.

To check the unfiltered fuel pressure, remove the plug from the fuel filter base. Install the connector, the seal and 1U-5470 Engine Pressure Group onto the fuel pressure tap. This will check transfer pump pressure. Operate the engine. To check the pressure within the main gallery, remove the plug from the fuel relief valve. Install the adapter, the seal and 1U-5470 Engine Pressure Group onto the fuel pressure tap. Operate the engine.

Note: Make sure that the fuel filter is clean before you check fuel pressure. A restricted fuel filter will cause a lower fuel pressure at the fuel filter tap than the fuel pressure at the fuel relief valve.

Finding The Top Center Position For The No. 1 Piston

Table 2

Tools Needed	Quantity
9S-9082 Engine Turning Tool	1

Note: The starting position for all timing procedures is with the No. 1 piston at the top center position on the compression stroke.

Illustration 3	g00361852
Locating the top center position (typical example) (1) The storage location for the timing bolt. (2) Plug. (3) Bolt. (4) Cover.

1. Remove the timing bolt (1), the bolt (3), and the cover (4) .

2. Remove the plug (2) .

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Illustration 4	g00361853
The location for 9S-9082 Engine Turning Tool (1) The installed timing bolt. (5) 9S-9082 Engine Turning Tool .

3. Install 9S-9082 Engine Turning Tool (5) in the housing.

4. Once plug (2) has been removed, insert the timing bolt (1) through the hole. Hold the timing bolt (1) against the flywheel.

5. Turn the flywheel in the direction of normal engine rotation until the timing bolt engages with the threaded hole. The No. 1 piston is at the top center position on the engine.

   Note: If the flywheel is turned beyond the point of engagement, the flywheel must be turned in the direction that is opposite of normal engine rotation. Turn the flywheel by approximately 30 degrees. Then turn the flywheel in the direction of normal engine rotation until the timing bolt engages with the threaded hole. When the No. 1 piston is at the top center position, this procedure will remove the play from the gears.

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Illustration 5	g00495276
Cylinder and valve location (A) Inlet. (B) Exhaust.

6. Remove the left front valve cover. Look at the valves of No. 1 cylinder. The valves will be closed if the No. 1 piston is on the compression stroke. You can move rocker arms up and down with your hand. If the No. 1 piston is not on the compression stroke, perform the following steps.

7. Remove the timing bolt from the flywheel.

8. Rotate the crankshaft counterclockwise by 360 degrees. Install the timing bolt.

Note: If the flywheel is turned beyond the point of engagement, the flywheel must be turned in the direction that is opposite of normal engine rotation. Turn the flywheel by approximately 30 degrees. Then turn the flywheel in the direction of normal engine rotation until the timing bolt engages with the threaded hole. When the No. 1 piston is at the top center position, this procedure will remove the play from the gears.

Engine Speed Measurement

Table 3

Tools Needed
Part Number	Part Name	Quantity
1U-6602 or 9U-7400	Tachometer Group (1) or Multitach	1

( 1 )

This unit is hand held.

Note: The Electronic Service Tools can also be used.

Observation of the electronic service tool display status screen gives the engine speed.

Illustration 6	g00286276
9U-7400 Multitach

The 9U-7400 Multitach can measure engine speed from a magnetic pickup. This magnetic pickup is located in the flywheel housing. The multitach also uses the ability to measure engine speed from visual engine parts that are rotating.

Note: Refer to Special Instruction, NEHS0605 that is with the 9U-7400 Multitach. This manual gives instructions for the test procedure.

The 1U-6602 Multi-Tachometer Group is a phototach for general use. This multi-tachometer group can only register the basic input frequency on any rotating part that is visible. The basic input frequency is 1 pulse per revolution per piece of reflective tape.

Note: Refer to Special Instruction, SEHS8854 that is with this group. This manual provides instructions for using this tool.

Note: The measurement of engine rpm can be set with the Electronic Service Tool. Refer to Electronic Troubleshooting.