Remove the diode relay and the fuel pump relay from the mounting block.
Wire a contact «87» fuel pump relay holder with terminal «+» battery, thus driving the fuel pump.
With the fuel pump running, slowly lift the pressure plate of the air mass meter manually or with a magnet. At the same time, a uniform resistance should be felt throughout the entire stroke of the pressure disc.
Slowly lower the pressure plate of the air mass meter and immediately lift it up, you should immediately feel resistance. If the movement of the pressure disc in any area does not require effort, then this indicates a sticking of the distribution plunger of the fuel quantity distributor.
Please note that the pressure disc must drop freely.