The Carter 320BL excavator engine cannot start and an oil pressure alarm appears after turning on the KEY for a few seconds. What is going on ?
Fault cause: Trem-A cab wiring harness pins 1# and 3# (terminal A) are shorted.
Troubleshooting method: repair wiring harness
Carter 320BL excavator engine cannot start, oil pressure alarm fault detection:
1. See the above after the KEY-ON. The phenomenon is considered to be an abnormal power supply at the L terminal of the generator. Use a multimeter to measure the voltage of the L terminal and it is 24 V - abnormal.
2. Disconnect connector 1 inside and outside the cabin and use a multimeter to measure continuity between 1-36# (generator terminal L) and the other connector terminals.
3. After measuring the cab exterior wiring harness connector, no neckrt-circuit was found with other wires.
4. After measuring the cabin wiring harness connector, it was found that there was a short between this terminal and terminal 1-35#, indicating that the short occurred at the interior of the cabin.
5. According to the analysis of the system diagram, inside the cabin, both terminals enter the monitor and ICF at the same time. In order to distinguish “component” or “wire harness” shorts, disconnect them. the ICF, then monitor and measure again, is still shorted, this is an internal short in the wiring harness.
6. Check the wiring harness carefully and finally find that there is a short circuit between terminals 1# and 3# in TremA.
Notes:
1. Terminal 1# of the TremA connector in the cab wiring harness is connected to the power-on signal via fuse 18#.
2. Connect terminal 3#from the TremA connector in the cab wiring harness to terminal L of the generator, and at the same time to terminal R of the starting safety relay and to terminal C7 of the monitor.
3. When both terminals are shorted, power flows from the 18# fuse to the R terminal of the starter safety relay when KEY-ON is activated. Therefore, the starter safety relay remains. unplugged and will not close, and the engine cannot start.
4. When monitor terminal C7 is energized, the monitor thinks the engine has started running and begins monitoring oil pressure. If the oil pressure is still low after a few seconds, a message appears. An oil pressure alarm will be issued.
5. This fault occurs on a machine that uses a 5-pin safety start relay. The phenomenon may be different on machines using a 4-pin start relay, please confirm.
The motorcycle generator has three wires, which is a three-phase magneto. To measure its voltage, you need to remove these three wires from the wiring harness, start the engine and use it. Multimeter AC voltage setting, measure the voltage between each of the two lines respectively. When you increase the throttle, the output voltage is around 50 to 80 volts.
The alternator output voltage should be measured when increasing the throttle. For motor models equipped with AC lighting circuits, the AC output must be greater than 25 volts. For motors equipped with DC lighting circuits, the AC output must be greater than 50 volts, otherwise the electricity production will not be sufficient.
The output voltage of the motorcycle alternator should be measured when increasing the throttle. For motor models equipped with AC lighting circuits, the AC output must be greater than 25 volts. For engines equippedFor DC lighting circuits, the AC output must be greater than 50 volts, otherwise the electricity production will not be sufficient.
Detailed information:
Motorcycle engine characteristics
1 The engine is a two- or four-stroke gasoline engine.
2. It adopts air cooling, including natural air cooling and forced air cooling. General models use natural air cooling, which relies on air blowing through the cylinder head and radiator on the cylinder liner to carry away heat while driving.
In order to ensure engine cooling at low vehicle speeds and before starting, high-power motorcycle engines adopt a forced air cooling method that installs fans and air ducts and uses forced air to blow the cooling fins.
3. The diet mThe motor is high, usually above 5,000 rpm. Power per liter (effective power emitted per liter of engine displacement) is important, generally around 60 kW/liter. This shows that the motorcycle engine has a high degree of reinforcement and the engine has a small overall size.
4. The crankcase, clutch and gearbox are designed to be integrated into a compact structure.
Specific method:
Set the DC mA setting of the multimeter to the smallest setting, connect the test leads to both ends of a certain group of three-phase windings, and then Connect the positive and negative terminals of the battery. Connect to the two wires of the other phase. As shown in the figure, when the switch is closed, if the needle swings to a value greater than zero, it means that the wire connected to the negative terminal of the battery and the wire connected to the multimeter probe are the same terminals (thetwo can be considered heads).
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