C13 and C15 Generator Set Engines Caterpillar

Air Inlet Restriction

There will be a reduction in the performance of the engine if there is an excess restriction in the air inlet system or the exhaust system.

Illustration 1	g00293196
1U-5470 Engine Pressure Group

Refer to Special Instruction, SEHS8907, "Using the 1U-5470 Engine Pressure Group" for the instructions that are needed to use the 1U-5470 Engine Pressure Group. Refer to Operation Manual, NEHS0818, "Using the 198-4240 Digital Pressure Indicator" for the instructions that are needed to use the 198-4240 Digital Pressure Indicator.

1. Check the Air Filter Change Indicator Group on the air inlet for a reading of the restriction.

2. Inspect the engine air cleaner inlet and ducting in order to ensure that the passageway is not blocked or collapsed.

3. Check for dirt tracks on the clean side of the engine air cleaner element, the air inlet hose, and the clamps. If dirt tracks are observed, contaminants are flowing past the engine air cleaner element, the seal for the air cleaner, and/or the air inlet hose.

4. Inspect the engine air cleaner element. Replace a dirty engine air cleaner element with a clean engine air cleaner element.
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   Hot engine components can cause injury from burns. Before performing maintenance on the engine, allow the engine and the components to cool.

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   Making contact with a running engine can cause burns from hot parts and can cause injury from rotating parts. When working on an engine that is running, avoid contact with hot parts and rotating parts.

5. Use the differential pressure gauge of the 1U-5470 Engine Pressure Group or the 198-4240 Digital Pressure Indicator.
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   Illustration 2	g01176673
   Air inlet system (typical example) (1) Turbocharger (2) Air Inlet Piping (3) Test location (4) Air cleaner

   1. Connect the vacuum port of the differential pressure gauge to the test location (3). Test location (3) can be located anywhere along air inlet piping (2) after engine air cleaner (4) but before turbocharger (1).

The air flow through a new engine air cleaner element must not have a system restriction of more than the following amount:

Maximum restriction ... 3.7 kPa (15 inch of H₂O)

The air flow through a used engine air cleaner may have an additional restriction. The air flow through a plugged engine air cleaner will be restricted to some magnitude. In either case, the restriction must not be more than the following amount:

Maximum restriction ... 6.2 kPa (25 inch of H₂O)

Exhaust Restriction

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The muffler and converter will become extremly hot during engine operation. A hot muffler and converter can cause serious burns. Allow adaquate cooling time before working on or near the muffler and converter.

Excessive idling can cause the muffler, or the catalytic converter/muffler to plug. A plugged muffler or a plugged catalytic converter/muffler will lead to an increase in exhaust back pressure. Operating the engine in extremely cold conditions may cause the muffler or the catalytic converter/muffler to plug. One indication of a plugged muffler or catalytic converter is poor engine response.

Exhaust Back Pressure for Mufflers and Catalytic Converters

Back pressure is the difference in the pressure between the exhaust and the atmospheric air.

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Hot engine components can cause injury from burns. Before performing maintenance on the engine, allow the engine and the components to cool.

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Making contact with a running engine can cause burns from hot parts and can cause injury from rotating parts. When working on an engine that is running, avoid contact with hot parts and rotating parts.

If the exhaust is not equipped with a back pressure tap, the following procedure may be use in order to install a pressure tap. Refer to Truck Engine News, SEBD6729, "Measuring Exhaust Back Pressure" for measuring the back pressure at a proper test location.

Use the differential pressure gauge of the 1U-5470 Engine Pressure Group or the 198-4240 Pressure Indicator Tool Gp in order to measure back pressure from the exhaust. Use the following procedure in order to measure back pressure from the exhaust:

High Idle Plugging Test

Note: Do not try to burn out a plugged muffler. The muffler can become severely overheated. An overheated muffler will cause other system components to fail.

1. Inspect the system components for any noticeable damage that would cause a restriction.

2. Connect the pressure port of the differential pressure gauge to test location. Refer to Truck Engine News, SEBD6729, "Measuring Exhaust Back Pressure" for measuring the back pressure at a proper test location.

3. Leave the vacuum port of the differential pressure gauge open to the atmosphere.

4. Start the engine. Run the engine in the no-load condition at high idle until the engine reaches normal operating temperature.

5. Record the value.

6. Multiply the value from Step 5 by 1.8.

7. Compare the result from Step 6 to the value that follows.

Back pressure from the exhaust must not be more than the following amount:

Maximum back pressure for engines with a standard muffler ... 10.0 kPa (40 inch of H₂O)

Maximum back pressure for engines with a catalytic converter/muffler ... 12.4 kPa (50 inch of H₂O)

If the maximum back pressure is within the allowable limits, refer to Troubleshooting, "Low/Power/Poor or No Response to Throttle".

If the back pressure exceeds 12.4 kPa (50 inch of H₂O), replace the muffler.

Illustration 3	g01403351
Exhaust system (typical example) (1) Turbocharger (5) Test location (6) Muffler (7) Exhaust piping

Full Load Test

Note: Do not try to burn out a plugged muffler. The muffler can become severely overheated. An overheated muffler will cause other system components to fail.

1. Check the arrangement number of the engine and verify that all components are correct.

   Note: Run the vehicle on a dyno up to 30 minutes in order to reach operating temperature. Monitor all of the engine components for any signs of overheating.

2. Measure the back pressure at a full load and full speed.

3. Record the results.

4. The back pressure for the catalytic converter/muffler is at 12.4 kPa (50 inch of H₂O).

5. Replace any components that have been proven damaged.

Data Sheet for Testing Catalytic Converters

S/N____________________

Miles ____________________

Date ____________________

Type of pressure gauge____________________

Mark the pressure test location with an "X" on the Illustration.

Illustration 4	g01183535

Engine speed ____________________ rpm

Engine load ____________________ percent

Back pressure ____________________ inches of water