PISTON AS 9T3885 - Caterpillar

The particulate trap exhaust filter will become restricted with ash and soot from the engine. The restriction will cause the back pressure of the exhaust from the DPF to increase. Testing the back pressure of the exhaust system will determine when the filter module and catalyst module needs to be cleaned.Testing Back Pressure
Table 1
Required Tools    
Part Number    Part Name    Quantity    
1U-5470
or
198-4240
or
220-3778     Engine Pressure Group
or
Digital Pressure Indicator
or
Adapter Cable As     1    
Illustration 1 g01337083
1U-5470 Engine Pressure Group
Illustration 2 g01335328
diagnostic module for the DPF (1) Mounting holes (2) "System status" (3) "Over-pressure alarm" (4) "Over-temp alarm" (5) "System problem" (6) "Alarm reset button" (7) "Pressure transducer port" (8) Wire passage (9) "Serial data comm port"Back pressure can be measured in many different ways. The diagnostic module for the DPF can be connected to a computer and port (9) with 220-3778 Adapter Cable As. You will be able to monitor the back pressure. The history of the back pressure can be downloaded. Refer to Special Instruction, REHS1342, "CRTdm Interface Software Guide".The back pressure can also be measured with 198-4240 Digital Pressure Indicator. Refer to Special Instruction, NEHS0818, "Using the 198-4240 Digital Pressure Indicator " for the instructions that are needed to use the tool.The 1U-5470 Engine Pressure Group can also be used to measure the back pressure. Refer to Special Instruction, SEHS8907, "Using the 1U-5470 Engine Pressure Group " for the instructions that are needed to use the tool.Back pressure measurements are required at the following intervals:
Amber dash light turns on.
Every 6 months
40,234 kilometers (25,000 miles)
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.
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.
Illustration 3 g01335329
Typical example (10) Inlet Module (11) Catalyst module (12) Filter module (13) Outlet Module (14) Test location (15) Tee fitting (16) Copper tubing (17) ThermocoupleNote: Do not test the exhaust back pressure if the "Over-pressure alarm" (3) has been activated. Clean the DPF. Refer to Operation and Maintenance Manual, SEBU7011, "Exhaust Filter (Particulate Trap) - Clean" for the proper procedure.
Remove Tee fitting (15) from test port (14). The test location is on the DPF.
Connect the pressure port of the differential pressure gauge to the test port.
Leave the vacuum port of the differential pressure gauge open to the atmosphere.Note: Watch the back pressure reading as the engine begins to warm up. Stop the test immediately if the back pressure goes above 25 kPa (100 inch of H2O). The filter module needs to be cleaned. Refer to Operation and Maintenance Manual, "Exhaust Filter (Particulate Trap) - Clean" for the proper cleaning procedure.
Start the engine and run the engine in the no-load condition at high idle until the engine reaches normal operating temperature.
Record the value while the engine