1. Used fuel pump
This type of fuel pump cannot be dry tested during maintenance of a long-used vehicle fuel pump. When the fuel pump is removed, there is fuel remaining in the pump housing. In the current test, once the brush has bad contact with the commutator, a spark will be generated to ignite the fuel in the pump housing and cause an explosion, which has very serious consequences.
2. New fuel pump
No dry test is allowed on the newly replaced fuel pump. Since the oil pump motor is sealed in the pump housing, the heat generated by electrification during dry test cannot be emitted. Once the armature is overheated, the motor will be destroyed. Therefore, the fuel pump must be immersed in fuel for the test.
3. Other aspects
After the fuel pump leaves the oil tank, the oil pump should be promptly wiped clean, and should be placed near it to avoid sparks, and follow the safety principle of "wiring first, electrifying later".