VALVE GROUP (R.H.) 7J8283 - Caterpillar

Table 4
Troubleshooting Test Steps    Values    Results    
2. Inspect the NRS for Leakage
A. Inspect the following components of the NRS for leakage:
1. Exhaust manifold
2. Connections for NRS cooler inlet and NRS cooler outlet
3. NRS venturi inlet and outlet connections
4. Port locations for NRS differential pressure sensor and NRS absolute pressure sensor
5. Connections for NRS inlet valve and NRS outlet valve
Common signs of a leak in the NRS are loose connections, damaged lines, or components and exhaust soot buildup around the area that is leaking.
   
Leakage    
Result: Leaks were found in the system.
Repair the leaks.
Reset all active codes and clear all logged codes. Use Cat ET to perform an "EGR System Test" in order to verify that the problem is resolved.
Result: Leaks were not found in the system.
Proceed to Test Step 3.
   
3. Use Cat ET to Perform an "EGR System Test"
A. Start the engine.
B.Use Cat ET to perform an "EGR System Test".
   
Test failed
   
Result: The "EGR System Test" fails due to "Delivered Fuel Volume Not Responding".
When the NRS gas flow is being commanded to change, no change in fuel delivery was measured. Increasing or decreasing the NRS gas flow will impact the amount of fuel needed to maintain the desired engine speed.
Proceed to Test Step 4.
Result: The "EGR System Test" fails due to "EGR Delta Pressure Not Responding".
The fault indicates that when the NRS valve moves from open to closed, no change in NRS delta pressure is measured.
Proceed to Test Step 5.
Result: The "EGR System Test" fails due to "EGR Absolute Pressure Not Responding".
The fault indicates that when the NRS valve moves from open to closed, no change in the NRS absolute pressure is measured.
Proceed to Test Step 6.
Result: The "EGR System Test" fails due to "EGR Mass Flow Rate Incorrect".
The fault indicates when the NRS valve moves from open to closed, the desired NRS mass flow is different from the actual mass flow rate.
Proceed to Test Step 4.
   
Illustration 3 g02259015
NRS valve (7) NRS actuator assembly (8) NRS valve body
Illustration 4 g01988657
NRS valve (9) Point of rotation
Table 5
Troubleshooting Test Steps    Values    Results    
4. Inspect the NRS Valve
A. Remove actuator assembly from NRS valve body.
B. Use a straight screwdriver to rotate the valve inside the NRS valve body. The valve should freely rotate from the open to close positions for 90 degrees of rotation.
   
Valve rotates freely    
Result: NRS valve does not rotate at all, or the valve is difficult to rotate.
Replace the NRS valve body and install the actuator assembly that was previously removed.
Reset all active codes and clear all logged codes by cycling the keyswitch to the Off position. Use Cat ET to perform an "EGR System Test" in order to verify that the problem is resolved.
Result: NRS valve does rotate freely from open to close.
Install new actuator assembly.
Reset all active codes and clear all logged codes by cycling the keyswitch to the Off position. Use Cat ET to perform an "EGR System Test" in order to verify that the