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How to Check and Install the Fuel Injector

If possible, the fuel injector can be directly installed on the fuel injector test bench for test and inspection according to the specified requirements. If there is no fuel injector test bench, it can be directly checked and adjusted on the diesel engine according to the following two methods provided by Yatong electromechanical:

(1) first prepare a standard injector (the injector) that meets the requirements of the injection pressure and the spray quality after checking and adjusting, and a three way connector, and install it on the oil outlet valve joint of the fuel injection pump (the fuel injection pump must supply normal).Put the throttle at the maximum oil supply position, reduce the pressure of the diesel engine, rotate the crankshaft at the speed of 100-200 R / min, and compare the standard injector with the inspected injector.

If the standard injector and the tested injector are injected at the same time, the atomization is good, the injection sound is clear and there is no oil dripping, it means that the injection pressure and atomization quality of the tested injector are qualified. If the tested injector injects fuel first or later than the standard injector, it means that the injection pressure of the tested injector is low or high. Adjust it, screw in or back off the pressure regulating screw until the tested injector is the same as the standard injector. If the two injectors inject oil at the same time, and the fuel atomization of the detected injector is poor, there is oil beam or oil drop, it means that there is a problem with the detected needle valve coupling, which needs to be repaired or replaced.

(2) If there is no standard injector and tee joint on hand, it can also be directly checked and adjusted on the diesel engine. The specific methods are as follows:

A. Remove the high-pressure oil pipe on the diesel engine, install one end of the high-pressure oil pipe on the oil inlet connector of the tested injector, one end on the oil outlet valve connector of the injection pump, and tighten the joint nuts at both ends of the high-pressure oil pipe;

B. Place the throttle handle at the maximum oil supply position. Under the normal oil supply condition of the fuel injection pump, rotate the crankshaft to make the diesel engine rotate within 100-200 R / min. at this time, the detected fuel injector injects fuel outside the cylinder to observe its atomization;

C. Turn the pressure regulating screw with a screw driver to make the injection pressure from low to high and the injection pressure from high to low. Repeat for 2 to 3 times. Select a place with good atomization quality, no oil beam, simple oil cut-off and no oil dripping. Fix the pressure regulating screw and continue to use. If the injector atomizes poorly all the time in the process of screwing the pressure regulating screw, there is oil spray, no injection sound and oil dripping, it means that the needle valve coupling of the injector cannot be used, and it should be replaced with a new one.

Before assembling the fuel injector, all parts must be cleaned thoroughly, especially the antirust oil on the new needle valve coupling parts. Precision parts must be washed in clean diesel and cannot be wiped with cotton. When installing, first install the parts on the upper part of the fuel injector body, i.e. ejector pin, spring, pressure regulating screw and other components. Note: do not tighten the pressure regulating screw at this time. After the upper part is installed, install the parts of the lower part of the fuel injector, the needle valve coupling and the fuel injector tightening cap. During installation, the pressure adjusting screw must be loosened first, and then the pressure screw can be adjusted after the fuel injection nozzle is installed and the combination nut is tightened. When correcting the injection pressure, it must be done on the injector calibrator. It is not allowed to test the injection pressure with the palm of your hand, which will be easily injured by the oil beam.

When the fuel injector is installed on the diesel engine, it is necessary to check in advance that the support shoulder of the mounting hole of the fuel injector shall be free of any nicks or cracks. Check again whether there are carbon deposits and stains left in the seat hole. If there is any, it must be cleaned thoroughly. Otherwise, the pressure of the fuel injector will not be tight, and the high-temperature and high-pressure gas will be ejected from the gap to burn the fuel injector, thus greatly reducing the service life of the fuel injector.

When installing the fuel injector on the engine, carefully check the height of the fuel injector protruding from the bottom of the cylinder head. If it is found that the installation height does not meet the specified requirements, the conical washer can be removed, and the appropriate gasket can be added between the fuel injector fastening screw sleeve and the conical washer body for adjustment, or the conical washer can be replaced. If it is found that the contact between the conical washer and the installation hole of the cylinder head is not tight, the conical washer can be removed by heating first and then cooling, so that its hardness can be reduced before installation. Before installation, use a special reamer to carefully remove the carbon deposit in the seat hole, so as to ensure that it is firmly fixed during installation. When tightening the two bolts of the fuel injector, make sure to use even force, otherwise it will easily cause the fuel injector to be skewed and incorrect, which will cause the engine to leak air or inject fuel outwards during operation.

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