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.
Required Tools | ||
Part Number | Part Name | Quantity |
1U-5470
or 198-4240 |
Engine Pressure Group
or Digital Pressure Indicator Gp |
1 |
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.
- Check the Air Filter Change Indicator Gp (if equipped) on the air inlet for a reading of the restriction.
- Inspect the engine air cleaner inlet and ducting in order to ensure that the passageway is not blocked or collapsed.
- 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.
- Inspect the engine air cleaner element. Replace a dirty engine air cleaner element with a clean engine air cleaner element.
Show/hide table
Hot engine components can cause injury from burns. Before performing maintenance on the engine, allow the engine and the components to cool.
Show/hide tableMaking 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.
- Use the differential pressure gauge of the 1U-5470 Engine Pressure Group or the 198-4240 Digital Pressure Indicator.
- Connect the vacuum port of the differential pressure gauge to test location (3). Test location (3) can be located anywhere along air inlet piping (2) after engine air cleaner (4) but before turbocharger (1).
Show/hide tableIllustration 2 g01176673 Air inlet system (typical example)
(1) Turbocharger
(2) Air Inlet Piping
(3) Test location
(4) Air cleaner
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 Back Pressure for Diesel Particulate Filters (If Equipped)
Illustration 3 | g01750120 |
diesel particulate filter (typical example) (5) Inlet section (6) Catalyst section (7) Filter section (8) Outlet section (9) Test location (10) Tee fitting (11) Copper tubing (12) Thermocouple |
Note: Limit the idle time of the engine to 20 minutes. If large quantities of soot are accumulated in the diesel particulate filter, running the engine can permanently damage the filter and other components. Avoid continuous idle time of the engine by using the idle shutdown timer. Refer to Troubleshooting, "Shutdown Timer (Idle) - Test " for using the idle shutdown timer.
Note: Do not test the exhaust back pressure if the red warning light has been activated. Clean the diesel particulate filter immediately.
Note: Refer to Special Instruction, REHS1807, "Installation Guide for Particulate Trap Exhaust Filters" for properly cleaning the diesel particulate filter.
- Inspect the system components for any noticeable damage that would cause a restriction.
- 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.
- Leave the vacuum port of the differential pressure gauge open to the atmosphere.
- Start the engine. Run the engine in the no-load condition at high idle until the engine reaches normal operating temperature.
- Record the value.
- Multiply the value from Step 5 by 1.8.
- Compare the test result to the value that follows.
Clean the diesel particulate filter if the back pressure exceeds the following value.
- Maximum back pressure for engines with a diesel particulate filter ...
25 kPa (100 inch of H2O)
Limit the idle time of the engine to 20 minutes. If large quantities of soot are accumulated in the diesel particulate filter, running the engine can permanently damage the filter and other components. Avoid continuous idle time of the engine by using the idle shutdown timer. Refer to Troubleshooting, "Shutdown Timer (Idle) - Test " for using the idle shutdown timer.
Note: Do not test the exhaust back pressure if the red warning light has been activated. Clean the diesel particulate filter immediately.
Note: Refer to Special Instruction, REHS1807, "Installation Guide for Particulate Trap Exhaust Filters" for properly cleaning the diesel particulate filter.
- 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.
- Measure the back pressure at full load and full speed.
- Record the results.
- The back pressure for the diesel particulate filter is at
24.9 kPa (100 inch of H2O) . - Replace any components that cannot be cleaned. Replace any components that are proven faulty.
Data Sheet for Testing Catalytic Converters or Diesel Particulate Filter
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