COUPLING 3H3387 - Caterpillar

Note: Refer to Systems Operation, Testing, and Adjusting, "Cleanliness of Fuel System Components" for detailed information on the standards of cleanliness that must be observed during ALL work on the fuel system.Ensure that all adjustments and repairs are performed by authorized personnel that have had the correct training. Adhere to proper safety guidelines for unit operation and fuel management practices.If air enters the fuel system, the air must be purged from the fuel system before the engine can be started. Air can enter the fuel system when the following events occur:
The fuel tank is empty or the fuel tank has been partially drained.
The low-pressure fuel lines are disconnected.
A leak exists in the low-pressure fuel system.
The fuel filter has been replaced.Use the following procedures to remove air from the fuel system:
Illustration 1 g03891128
Typical example
Ensure that the fuel tank is full and any fuel valve (if equipped) is in the "ON" position.
If the application has a gravity feed fuel system, then loosen vent screw (1) and allow fuel to flow. When fuel free from air comes from the vent screw, tighten the vent screw (1) by hand . If the fuel system is not a gravity feed fuel system, then go to Step 3.
Illustration 2 g03891159
Typical example
Loosen the vent screw (2) on the secondary fuel filter.
Turn the battery disconnect switch to the "ON" position.
On the EMCP, configure relay output 5 to "Auto Mode" from "Fuel Control Relay".
Push "AUTO" on the EMCP display. This will allow the electric priming pump to operate. When fuel free from air comes from the vent screw (2), tighten the vent screw securely. Then, operate the electric priming pump for an extra 2 minutes.
Push "STOP" on the EMCP display. The fuel system should now be primed.
The configuration of relay output 5 MUST be changed back to "Fuel Control Relay" from "Auto Mode". Now the engine is ready to start.
Push "START" on the EMCP to crank the engine. After the engine has started, operate the engine at low idle for a minimum of 5 minutes. For constant speed engines do not apply load for 5 minutes.Note: Operating the engine for this period will help ensure that the fuel system is free of air.DO NOT loosen the high-pressure fuel lines to purge air from the fuel system. This procedure is not required.
Ensure that the fuel system is free of leaks.
After verifying that the system is free of leaks, push "STOP" on the EMCP.
Turn the battery disconnect switch of the "OFF" position.After the engine has stopped, you must wait for 10 minutes to allow the fuel pressure to be purged from the high-pressure fuel lines before any service or repair is performed on the engine fuel lines. The 10 minute wait will also allow static charge to dissipate from the low-pressure fuel system. If necessary, perform minor adjustments. Repair any leaks from the low-pressure fuel system and from the cooling, lubrication, or air systems. Replace any high-pressure fuel line that has leaked. Refer to Disassembly and Assembly Manual, "Fuel Injection Lines