Why should a broken nozzle be completely replaced?

The damaged nozzle does not need to be completely replaced. Generally speaking, only the broken nozzles need to be replaced, not all of them.

If the nozzle is worn, it must be replaced. It is recommended to use high-quality original nozzles instead of calibrated nozzles in the market.

But from another point of view, a repair is not easy. If the price is not unacceptable, it is ok to replace all the injectors, because one is broken and the others will be fine.

Therefore, replacing one nozzle with four is only a sales promotion method of the repair shop, and it has no special significance.

Brief introduction of fuel injector:

As the supply terminal of the engine fuel supply system, the fuel nozzle plays an important role in injecting fuel into the cylinder at a certain pressure and time.

How to check the injector without signal? Generally, each injector has a power line controlled by the main relay or oil pump and a signal line controlled by the engine computer ECU. There must be power supply and ECU control signal to work. If there is no control signal on the signal line controlled by ECU, it is necessary to check whether the ignition system is abnormal, otherwise ECU will not give the fuel injection signal.

Of course, some people may say that at present, the engine adopts high-pressure common rail technology, and the precise control of injection time and injection quantity is mainly realized by electronically controlled injectors. However, in the long-term use process, the accuracy and efficiency of the injector will gradually decline.

If only one injector is replaced, the performance of the new injector is better than that of the old injector in all aspects, and the power of each cylinder will be uneven when the engine works, resulting in engine jitter and power reduction. But this is often a set of rhetoric in theory, and we don't have to follow this criterion completely in the practical application process.