Transistor electric gasoline pump in use, there may be insufficient pump oil or not pumping phenomenon. If you turn on the power, you can hear a slight "嘣, jumped" sound, hand touching the shell can feel slight vibration, but the hydraulic pressure is insufficient, the circuit part of the normal, may be out of the valve, into the valve or Back to the oil valve and its seat between the dirt, damaged the seal may also be blocked oil, return spring lack of elasticity, the plunger worn even with the gap between the pump cylinder is too large, should open the pump oil part of the inspection And clean. If you find a small bubble in the oil cup, then the failure of gaskets leak or inlet pipe leaks, should be ruled out. If the power is turned on, the pump does not pump oil, you should first determine the fault is in the circuit part or in the mechanical part. The method is as follows: Use small test light to check the power is on (for the sake of safety, do not use the scratch method), such as power connected, and then with an ammeter (O-5A) into the circuit, if the ammeter pointer around 1A Jitter, indicating part of the circuit is normal, the failure is in the mechanical part, the pump cover should be disassembled, check whether the plunger in the cylinder is stuck by dirt, and the position of the valve, the inlet valve and other parts are normal. If the ammeter does not move or the current exceeds 2A, then the control circuit is faulty.