W124 260E runs only with EHA valve disconnected
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W124
W124 260E runs only with EHA valve disconnected
Hi! I own a '91 W124 260e (103.940) with a catalytic converter which won't run with the EHA valve connected. Everything started when I was doing some work under the hood, and noticed that the EHA wires were connected in a wrong way (the black wire was paired with pin no. 2 and the black/brown wire was paired with pin no. 1). When I switched the order (to the correct one), the car wouldn't start. It would crank but never start. As soon as I disconnect the wires, or reconnect them to the wrong pins, everything goes back to normal. I've tried to start the car with EHA wires disconnected and then to plug them in when the engine was running. As a result, the engine stalled. I've tried to restart it, but again, it would only crank. I've measured the current at the EHA with the ignition on and the wires plugged in (correctly), and it turned out it's smaller than the specified value (14.90mA instead of 20mA). Next, as the maintenance manual suggests, I've checked the ohm rating for the EHA valve and it seems it's fine (specification 19,5 +/- 1 ohm, mine 20 ohms). Also, I've checked the ohm rating for the R17 resistance plug, and it seems to be fine too. The last suspect left according to the manual was the ECU. I've replaced it with a used one, but nothing changed. Reading of the current is still the same as well as the EHA issue. Any ideas and suggestions on how to solve it will be greatly appreciated.
