[QUOTE=Rusty Boltz;1317266]As Minnet stated, the EHA controls the mixture. This is done through the fuel distributor which rapidly switches between high and low pressure chambers to get the proper flow.
QUOTE]

I may be wrong, but as well as I know, the EHA has a blade inside, which is spring loaded and will be rotated in one or the other diriction proportional to the current flow in it.

Functionally it is in parallel with the piston inside the fuel distributor, and in this way together they will determine the pressure in the lower chamber of the differential pressure valves, thereby determining the fuel pressure to the injectors. The fuel distributor piston is mechanically controlled by the air mass sensor plate will make the coarse adjustment proportional to the airflow, and the EHA will make the fine adjustment according to the feedback from the oxygen sensor.

In open loop mode, it will just work mechanically without electronic feedback. In fact, this was basically how it worked until it got the "E".

The reason why it will rapidly change for more or less pressure is because it is continuously correcting the mixture.

If someone knows for sure, please let us know.

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1991 300SEL (W140)
1987 190E 2.3 (W201)
1987 Honda Accord 2.0