Case 1
Trouble symptoms: The starter and the engine both have normal starting speeds, but they do not catch fire; or sometimes they can catch fire after many long periods of starting.
Cause: There is air in the fuel line.
Nature of failure: mechanical failure.
Treatment method: exhaust air from the fuel line.
Failure analysis: National III vehicles use a common rail system, and it is relatively difficult to exhaust air from the oil circuit. Often, the operator feels that the air is cleaned out, but it is actually not completely exhausted. According to the actual use situation, the oil pump return bolt should be loosened to exhaust air, and if necessary, the high-pressure oil pipe can be loosened, and the starter can be used to drive the engine idling to exhaust air; if it is only to loosen the bleed screw of the fuel filter Exhausting air may not be easy to completely exhaust the air in the fuel line, which is more laborious.
Case 2
Trouble symptoms: Both the starter and the engine have normal starting speeds, but do not catch fire.
The cause of the failure: the diesel pipeline or the oil-water separator is blocked.
Nature of failure: mechanical failure.
Treatment method: clean the diesel pipeline or the oil-water separator, drain the water separator, replace it if necessary, and finally exhaust the oil circuit completely.
Failure analysis: The diesel filter or oil-water separator of the National III engine needs to be maintained frequently, and the maintenance period is much shorter than that of the previous engine. (There is also a situation, if the inner diameter of the oil inlet hose or the oil return hose is too thin and too long, the oil inlet and return are not smooth, and the more serious ones will also make the engine start difficult or unable to start. At this time, it needs to be replaced. The required oil inlet and return pipes should have an inner diameter of 12 mm or more).
Case 3
Trouble symptoms: Both the starter and the engine have normal starting speeds, but do not catch fire.
Failure reason: ECU has a failure code.
Nature of failure: electrical failure.
Solution: Clear the fault code.
Fault analysis: The car is normal from the mechanical inspection, and it is found that there are some fault displays such as “water temperature sensor”, “rail pressure sensor”, “accelerator pedal” and so on with the diagnosis instrument. After the fault code is cleared, the engine starts smoothly. In this case, it is estimated that the maintenance or operation personnel performed the operation of plugging and unplugging the connectors of the electronic control system under power. In this way, the system will generate a fault code and store it in the ECU. The protection of the system will limit some functions or even fail to start.
Case 4
Trouble symptoms: Both the starter and the engine have normal starting speeds, but do not catch fire.
The cause of the failure: the engine harness is damaged or the connector is in poor contact.
Nature of failure: electrical failure.
Treatment method: replace the engine wiring harness or re-plug the connectors (note: at this time, the power must be turned off).
Failure analysis: The engine wiring harness is not likely to be damaged, and there are more cases of poor contact. Do not easily replace the engine wiring harness until the cause of the poor contact of the connectors has not been eliminated. At this point, you can use the diagnostic tool to diagnose the approximate area where the fault occurred, and then eliminate it.
Case 5
Trouble symptoms: Both the starter and the engine have normal starting speeds, but do not catch fire.
The cause of the failure: the timing of the oil pump installation is incorrect or the flywheel does not match.
Nature of failure: mechanical failure.
Treatment method: reinstall the oil pump or replace the matching flywheel.
Failure analysis: This situation generally occurs on engines that have replaced oil pumps or flywheels. For engines with installation timing requirements for the oil pump (such as 6DL1 National III engines), the oil pump must be installed correctly; in addition, if the flywheel is replaced, the surrounding belt must be used. Original flywheel with signal sensing hole.
Case 6
Trouble symptoms: Both the starter and the engine have normal starting speeds, but do not catch fire.
The cause of the failure: The plug-in position of the oil pump pressure control valve (PCV) is installed incorrectly.
Nature of failure: electrical failure.
Solution: Re-plug and install (turn off the power first).
Failure analysis: This situation generally occurs on the 6DL1 country III engine that has removed the oil pump or PCV valve connector. It uses Denso’s oil pump. There are two PCV valves. The position of the connector is easy to be confused. You need to pay attention to the mark when installing. Generally, it is the flywheel end of the line tied with colored tape.
Case 7
Trouble symptoms: Both the starter and the engine have normal starting speeds, but do not catch fire.
Cause of failure: NE (speed) sensor and G (camshaft) sensor failed at the same time.
Nature of failure: electrical failure.
Treatment method: replace.
Failure analysis: This situation generally does not occur much. When tested with a diagnostic instrument, the NE (speed) sensor and G (camshaft) sensor are both faulty.
Case 8
Trouble symptoms: Both the starter and the engine have normal starting speeds, but do not catch fire.
Cause of failure: failure of high pressure common rail pipe.
Nature of failure: electrical failure.
Treatment method: replace.
Failure analysis: This failure is sometimes the rail pressure sensor failure, sometimes it is the rail pressure control valve failure. If the rail pressure control valve is always open, the rail pressure cannot be established and thus cannot be started.
Case 9
Fault symptom: The starter has no speed.
Cause of failure: no power supply, insufficient voltage or starter failure.
Nature of failure: electrical failure.
Treatment method: turn on the power supply or replace the starter or charge the battery.
Fault analysis: The starter current will burn out or the ring gear will not be able to mesh with the flywheel; if the voltage is insufficient, the engine cannot reach the starting speed.
Case 10
Trouble symptoms: Both the starter and the engine have normal starting speeds, but do not catch fire.
The cause of the failure: the car neutral switch or clutch switch failure
Nature of failure: electrical failure.
Treatment method: replace.
Failure analysis: This failure should belong to the entire vehicle failure.
