THERMOSTAT AS 4973993 - Caterpillar

Illustration 6 g06051627
(7) High-pressure fuel supply line
Disconnect high-pressure fuel supply line (7) from the high-pressure fuel pump.
Illustration 7 g06051850
(6) 356-2470 Graduated Cylinder
(8) 323-8301 Pump Drain Hose
Connect pump drain hose (8) to the high-pressure fuel pump outlet.
Route the hose to graduated cylinder (6).
Crank the engine for 20 seconds and record the fuel volume.
The volume of the fuel is less than 40 mL (1.4 oz). Replace the high-pressure fuel pump. Proceed to Test Step 5.Note: Ensure that the low-pressure fuel system is providing a minimum of 210 kPa (30.5 psi) during the cranking process.
The volume of the fuel is greater than 40 mL (1.4 oz). Replace the previous fuel line that connects the high-pressure fuel pump to the fuel rail with a new line. Proceed to Test Step 3.Test Step 3: Measure the Pressure of the Fuel Rail while Cranking
Illustration 8 g06051890
(7) High-pressure fuel supply line
(9) 323-3950 Discharge Orifice AsNote: Illustration 8 shows discharge orifice assembly (9) attached to injector supply line number 3. The discharge orifice assembly can be installed to any injector supply line as long as the other 5 injectors ports are plugged on the fuel rail.
Remove the fuel lines for the injectors from the fuel rail.
Install the 323-3951 Rail Plug As on the rail for cylinders 1, 2, 4, 5, and 6.
Use the 355-8794 Gage Pin to ensure that the discharge orifice is free of any obstruction.
Illustration 9 g06051907
(9) 323-3950 Discharge Orifice As
Install discharge orifice assembly (9) on injector port 3. Route the discharge orifice assembly hose to the 356-2470 Graduated Cylinder.
Use the Cat® Electronic Technician (ET) "Injection Disable Override" to disable the fuel injectors or disconnect the fuel injectors electrical connector on the side of the cylinder head.Note: Leave the injectors disabled during the test.
Navigate in Cat ET to the "Status Parameters > Fuel Delivery" screen. Record the "Fuel Rail Pressure" and "Engine Speed" while the engine cranks for 10 seconds. Refer to Table for the minimum values for fuel rail pressure in relation to the engine speed.
Table 3
Engine Speed Range (rpm) 150-174 175-199 200-224 225-250 250-274 275-300
Minimum Cranking Pressure (Mpa/psi) 3640 kPa (528 psi) 5620 kPa (815 psi) 7600 kPa (1102 psi) 10260 kPa (1488 psi) 12910 kPa (1872 psi) 16000 kPa (2320 psi)
The fuel rail pressure remains less than the minimum fuel rail pressure rated against the engine speed listed in the table. Replace the high-pressure fuel pump. Proceed to Test Step 5.
The fuel rail pressure is greater than or equal to the minimum fuel rail pressure rated against the engine speed listed in the table. Proceed to Test Step 4.
Remove the discharge orifice assembly from the fuel rail.Test Step 4: Measure the Leakage for Individual Injectors
Illustration 10 g06052175
(10) Injector 3 fuel supply port
(11) Injector 4 fuel supply line
Connect the fuel supply line for one of the injectors (11) to the high-pressure fuel rail. Plug the other 5 injector ports using the 323-3951 Rail Plug As.Note: Leave the injectors disabled for the duration of