0302871 JOHNSON SCREW,Rear

Personal injury or death can result from improperly checking for a leak.Always use a board or cardboard when checking for a leak. Escaping air or fluid under pressure, even a pin-hole size leak, can penetrate body tissue causing serious injury, and possible death.If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products.Dispose of all fluids according to local regulations and mandates.
Ensure that all adjustments and repairs that are performed on the fuel system are performed by authorized personnel. Ensure that these personnel have had the correct training.Before beginning any work on the fuel system, refer to Operation and Maintenance Manual, "General Hazard Information and High-Pressure Fuel Lines" for safety information.Refer to Systems Operation, "Cleanliness of Fuel System Components" for detailed information that is related to the standards of cleanliness that must be observed during all work on the fuel system.
Note: The fuel pressure in the fuel system must be below 1 MPa (145 psi) before the fuel system can be serviced. Refer to Systems Operation/Testing and Adjusting, "Fuel Rail Pressure - Release".Excessive bypass fuel flow by individual fuel injectors can affect engine starting, engine operation, and engine performance.Note: There are two different configurations for the injector bypass fuel line. One configuration routes the bypass line through a check valve to the fuel manifold on the back side of the high pressure fuel pump. This fuel then returns to the fuel tank. The second configuration connects to pressurised fuel on the inlet of the transfer pump.
Use the following procedure to check the fuel injectors for excessive bypass fuel flow:
Illustration 1 g06089454
(1) Fuel return line from the fuel injectors
(2) Fuel manifold
Illustration 2 g06089421
Alternate injector bypass fuel flow line of 20 cylinder engine
(3) Fuel return line from the fuel injectors
(4) Low-pressure fuel line
Illustration 3 g06089432
Alternate injector bypass fuel flow line of 16 cylinder engine
(5) Fuel return line from the fuel injectors
(6) Low-pressure fuel line
Disconnect the fuel injector fuel return line (1) from fuel manifold (2) at the high-pressure fuel pump or from the alternate line (3) or (5) on the low-pressure fuel system. Obtain a piece of plastic tubing that can be attached to the end of the return line. Connect one end of the tubing to the loose return line. Place the other end of the tube into a suitable container that can be used to measure the fuel discharge from the return line.
Plug the fitting where the injector bypass fuel flow line was connected (2), (4), or (6). Plugging will ensure no fuel sprays out when the engine is started.
Start the engine. Allow the engine to stabilize at a steady engine rpm.
Illustration 4 g02246114
Injector bypass fuel flow that is allowable for the engine
Note: During engine cranking, the flow rate should be minimal to zero. Refer to Illustration 4 to determine if the flow rate during engine cranking is excessive
Measure the flow rate that drains from the return line for one minute. Use the Illustration that is shown above to determine if the flow rate for the engine is excessive.Stop the engine.If the fuel flow rate is acceptable, clean up any fuel that may have been spilled. Reconnect the fuel return line to the fuel manifold. Return the engine to service.If the fuel flow rate is greater than the acceptable value shown in Illustration 4, leave the fuel return line disconnected from the fuel manifold. Proceed to the next Test Step to locate any problem injectors.
Use the following procedure to check the injector bypass fuel flow for each cylinder bank:
Illustration 5 g01859040
Location of the fitting for the crossover tube for the fuel return line (left rear engine view)
Disconnect the crossover tube for the fuel return line that is on the left rear side of the engine. Obtain two pieces of plastic tubing that can be used to collect the fuel drain from each fitting. Connect one of the pieces of tubing to loose return line. Connect the other piece of tubing to the fitting that is at the support of the fuel rail. Place the end of tubes into suitable containers that can be used to measure the flow rate that drains from each of the fittings.
Plug the fuel line at the fuel manifold or at the fittings for the alternative lines (4) or (6) identified in the step 1 of this procedure. Plugging will ensure that the fuel pumped into the injector bypass line is fuel from the injectors only.
Start the engine. Allow the engine to stabilize at a steady engine rpm.