Electro-Hydraulic Actuator Valve (000 070 39 62)

Electro-Hydraulic Actuator Valve (000 070 39 62)

The EHA (Electro-Hydraulic-Actuator) is an electrical valve that controls the pressure on fuel distributor. The duty cycle of the EHA valve is determined by the O2 sensor. The EHA valve is only used on vehicles with the KE-JETRONIC fuel injection system.

Part number(s): 000 070 39 62
Used on: M102, M103, M104, M116, M117, M119

A bit of background on the EHA's function: it is an electronically controlled servo (controlled from the CIS-E main computer) that uses a variable current to make the last, minute adjustments to the fuel flowing into the fuel distributor and then into the combustion chambers. It does this by maintaining an appropriate differential pressure between the upper and lower chambers of the CIS-E fuel distributor. Essentially, depending on the current, the EHA is sort of a controlled fuel leak that can either richen or lean out the mixture based on its fixed adjustment, and the current that provides its inputs. The EHA works in conjunction with the fuel-air mixture adjustment (duty cycle) as described earlier. The EHA is sort of a final compensation in the system to try to keep it within proper operating parameters. If something else in the fuel/air system is not set or working correctly (for example, the idle air control “silde” valve, or the air/fuel mixture is not set correctly) then the EHA will do its best to try to keep things in check. If they are too far out of whack, then the EHA can only do so much given its parameters. ¹⁾