The most common problem in engine failure is failure to start. There are many causes of this problem such as oil, electrical, fuel line and mechanical failures. It is impossible to summarize the idea of investigating this problem in a single sentence. Therefore, troubleshooting should be done in a step-by-step, methodical manner, from the outermost to the innermost components, and from shallow to deeper problems, depending on the specific type of failure. Today, we will discuss troubleshooting methods for the different fault types that cause an engine not to start.
This is a new car with a distance of 0 km. In case of the above situation, the diagnostic instrument drops during the taxi, and the oil output of the oil pump is abnormal. Sometimes it is accompanied by some fault codes. Generally, the diagnostic instrument drops during the taxi, and these fault codes are basically caused by the virtual connection of ECU power supply and grounding or T15. When troubleshooting, focus on troubleshooting the harness.
If the starter does not turn, the rail pressure and synchronization must be abnormal. When you see such problems, you should not pay attention to synchronization and rail pressure, but focus on why the starter does not turn? The common reasons why the starter does not run are as follows:
The most common components that cause the engine to fail to meet the starting conditions are neutral switch and clutch switch. There are three strategies for neutral switch and clutch switch to participate in starting control:
If the starting signal meets the starting conditions, turn the key to st gear, and the state of “control signal of starting relay” changes, but the starter does not turn. At this time, we should check the following points:
The above points are all routine methods, which are easier to check. There are often such problems reported by the master: when the metering unit is normally open, pull out the harness, the oil pump will discharge oil, and the oil will not be discharged when it is plugged in; Or the normally closed metering unit, remove the rubber ring for oil discharge, and install it without oil discharge.
When you encounter the problem that the fuel injector is not powered on in the future, you should pay attention to the above points, especially remember to ask the driver if he owes money. Whether the ECU energizes the fuel injector can be seen from the actual fuel injection quantity. At the same time, it can also be detected with a test lamp. Connect a diode test lamp to the fuel injector harness. If the test lamp flashes, it indicates that the fuel injector has been powered on, otherwise it is not powered on.
If the fuel injector has been powered on, but the engine still cannot be started, what needs to be checked?
A. First, check whether there are problems with the fuel injector itself.
How to evaluate whether the performance of an injector is normal? How many criteria are there?
B. Is the fresh air volume, intake air temperature and engine temperature normal
If the exhaust gas in the cylinder is too much and the temperature is too low, it will not work even if the fuel is injected.
C. Cylinder itself
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