I couldn't detect any current going to the idle valve or the EHA valve. I did that at idle. Howevr, car idles fine. I get about 300 miles before the gas light comes on. Black smoke out the muffler under hard kick down....> assumes rich mixture. Sometime I smell gas when exiting a highway (while the car is turning). I assumed my OVP is bad. Fuse on top is fine. I ordered a new OVP (new style with 2 10 Amps fuses ) and will be here next Tuesday. Any suggestions like another fuse or relay to check. Is the operation of the O2 sensor is effected by the OVP in any way?
Thank you all,

Meza

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Meza
1993 190E 2.6
Advanced Diesel Systems Test and Research Engineer

The OVP is a relay with a series fuse. Other than the fuse blowing, the only thing that can consistently cause it to be 'open circuit' is if the relay coil fails, but I think you would have your ABS light on then. If the relay contacts are poor, the symptom would be problems with idle and running. You might look for sensor inputs that have failed, e.g. O2 sensor or crank sensor, causing it to default to limp mode.

Steve