HOSE AS 8W4342 - Caterpillar

3408E (7PR),
3412E (4CR) Industrial EnginesThere are several possible causes for 3408E and 3412E Engines that are difficult to start or will not start, or engines that will start but will not continue to run. Refer to the service manual for mechanical and electronic troubleshooting information and procedures.
Perform the following checks:
1. Visually check the fuel level and oil level. Verify minimum fuel and oil pressures.2. Check for correct installation of the Electronic Control Module (ECM) connectors, speed/timing sensor connector, and the unit injector connectors. Verify that the ECM is receiving the correct voltage.3. Check the injection actuation pressure control valve seals.4. Use Electronic Technician (ET) to check for faults and logged events. While the engine is cranking, observe the engine speed to verify that the speed/timing sensor circuit is operating correctly. Verify that actual injection actuation pressure and current are normal.Also refer to Power Connection Broadcast video and handouts for January 1999 (LEVN4568).
Since the 3408E and 3412E Fuel Injectors are actuated by oil pressure, the Injection Actuation Pressure System could be one possible cause. To begin troubleshooting a 3408E or 3412E Engine that is hard to start or starts and dies, compare the actual and desired injection actuation pressures while the engine is cranking. The actual and the desired injection actuation pressures should be approximately the same value. Some fluctuation in the actual injection actuation pressure is normal. If the fluctuation is extreme, there may be a possible problem with the compensator control valve or the hydraulic pump. A customized ET screen like this one is helpful for checking the Injection Actuation Pressure System.
An optional parameter for this screen would be the engine oil temperature.
Here are four possible situations that would not allow the engine to start or to start but not run properly:
Injection Actuation Current is 100% and Actual Injection Actuation Pressure is Low
If the injection actuation current is at 100% and the actual injection actuation pressure is low, there is possibly a leak in the injector or the jumper tube that provides the oil to the injector. The minimum pressure required to enable the injector is approximately 4500 kPa (650 psi) and the normal operating range is 5000 kPa to 21 000 kPa (725 to 3100 psi). The pressure must be 5000 kPa (725 psi) for the engine to start. 1800 kPa (260 psi) is the default value for the sensor.
When inspecting the engine for oil leaks, first check the engine when it is cold by just cranking and not allowing the engine to start. If there are no visible leaks, then run the engine (if it will start) until it reaches operating temperature. Leaks will be much more visible when the oil is warm and under pressure.
Hot oil and hot components can cause personal injury. Do not allow hot oil and hot components to contact the skin.
First remove the valve covers and disable all unit injectors using an ET service tool, ground level shutdown switch, or by disconnecting the injector wiring in the valve cover base.