To achieve optimal and continued performance from your Perkins engine, regular maintenance of your fuel injection system is highly recommended.
The high-pressure fuel lines run between the high-pressure fuel pump and the high-pressure fuel manifold, and between the fuel manifold and cylinder head. They are different from other fuel system lines because:
- When running common rail systems, high-pressure fuel lines are constantly charged with high pressure
- The internal pressures of the high-pressure fuel lines are higher than other types of fuel system
- The high-pressure fuel lines are formed to a specific shape and then strengthened by a special process
Electronic engines will have a fuel pressure sensor in the fuel manifold or fuel system which sends information to the Electronic Control Module (ECM) to enable a warning indicator to be lit to advise of a condition which could result in a reduction in engine performance. Diagnostic indicators are also used to indicate warnings such as; throttle position sensor, fuel rail pressure and high-pressure fuel pump faults. For more information on warning lamps and the codes, please see your Operation and Maintenance Manual (OMM). Fault codes are also logged in the ECM, which can assist with the diagnosis of faults.
Fuel injection pumps
The fuel injection pump is key to ensuring the engine meets local emission standards. If any adjustments to the fuel pump timing and high idle are required, you must refer to your local Perkins distributor.
How to prime
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 fuel tank is filled while the engine is running
- The low-pressure fuel lines are disconnected
- A leak exists in the low-pressure fuel system
- The fuel filter has been replaced
- After daily water drain procedure
- Replacing high pressure fuel lines or system component
For mechanical engines this basic procedure can be used to prime the fuel system in the engine.
- Loosen vent screw on fuel filter assembly
- Operate priming pump
- When fuel flow from the vent runs free from air tighten the vent screw
Note, some fuel systems use gravity to prime the fuel filter. If gravity is used, ensure that the fuel tank is full and all the stop valves in the fuel line are open.
Depending on the engine there are 4 different types of priming pump; hand priming pump, in-line hand priming, electrical or transfer pump, check the OMM for details of the correct procedure.
Priming engines with a high-pressure common rail is much easier,
400 Series electronic engines;
- Switch the engine on for 2 minutes
- Switch off
- Switch on again. The engine is primed and ready to start.
1200 Series engines;
- Turn the key switch to the run position.
- The system will enable to the electric priming pump to run
- After 2 minutes the ECM will switch the pump off
- Turn the key switch to off. The fuel should now be primed
- Switch the engine on and run for at least 5 minutes at low idle to ensure the system is fully operational.
Full information on priming your engine is available in the OMM. It is very important that you do not loosen any high-pressure fuel lines to purge air.
Checking fuel lines
Fuel system hoses and clamps are often areas of failure. Visually inspect fuel system hoses and clamps at a regular basis for damage or signs of fuel leakage, as leaks are often caused by cracking, softness or loose clamps. To inspect the high-pressure fuel line, switch off the engine and wait for the fuel pressure to be purged from the line before any inspection, service or repair is performed.
Replace hoses that are cracked or soft and tighten any loose clamps. Check for the following conditions; end fittings that are damaged or leaking, outer coverings that are chafed or cut, or ballooning locally, flexible hoses that are kinked or crushed and armouring that is embedded in the outer covering.
Tighten all connections to the recommended torque. If there is a leak do not over-tighten the connection to stop the leak. If high-pressure fuel lines are leaking the fuel lines must be replaced.
Be aware
- Do not operate the engine with a fuel leak. Leaks can cause fires.
- Do not step on the high-pressure fuel lines, bend or strike the high-pressure fuel lines. Deformed or damaged high-pressure fuel lines are a point of weakness and a potential cause of failure.
- Do not loosen the high-pressure fuel lines to remove air from the fuel system. This procedure is not required.
- Make sure that all clamps, guards, and heat shields are installed correctly. During engine operation, correct installation will help to prevent vibration, rubbing against other parts, and excessive heat.
- Drain the water and the sediment from the fuel tank weekly to ensure that only clean fuel enters the fuel system.
Depressurisation of fuel system
Before any repairs to the hoses or fuel system, the engine must be stopped, and the fuel pressure reduced, to prevent hazard or risk of fire. This allows the fuel pressure to be purged from the high-pressure fuel lines.
Before starting any work;
- High pressure fuel systems - stop the engine and leave for 60 seconds.
- Electronic 1200, 900 and 400 Series engines – stop the engine and leave for 10 minutes.
Do not loosen high-pressure fuel lines to remove air pressure from the system. The 10-minute wait will also allow static charge to dissipate from the low-pressure fuel system.
For full instructions on how to prime, change fuel filters and check the fuel system refer to your OMM.