The reasons why the air pump cannot be suppressed are as follows: 1. Motor lack of phase: the motor can't output rated power due to motor lack of phase, which limits the maximum output pressure of the air pump (when the air pump pressure rises, the motor load gradually increases and the power gradually increases). At this point, you can check the circuit. 2. Air pump seal damage: especially the piston head seal damage leads to air leakage between high and low pressure chambers. The common air pump is a piston air pump similar to a hydraulic cylinder. There is a seal on the piston head for a long time, and the seal is likely to fail due to normal wear or aging, resulting in air leakage between the high-pressure chamber and the low-pressure chamber, leading to pressurization failure. At this point, it is necessary to disassemble the air pump compressor and then replace the seal. This is the biggest possible reason why the air pump is not pressurized. 3. The pressure limiting valve is set too low: for safety reasons, a pressure limiting valve will be set at the outlet to avoid the danger of explosion caused by excessive pressure. The set pressure of the valve is too low. Every time the pressure reaches the limit value, the air pump will automatically stop, reflecting that the air pump cannot boost the pressure. But the air pump can always work normally at this time. Million car purchase subsidy