Check the fuse In the Ovp. This will cause the same symptom.

You can check your wires with a ohm meter. I do not know what the resistance should be and I will check my old ones and my new ones to see if there is any difference. The other way to check your wires is simply open the hood start the car and look at the wires at night time, in as dark of a setting as you can get. Preferably in the garage with the lights off with the garage door slightly open to let the fumes out. DON'T run for too long you don't want to get dizzy or passout from the fumes nor do you want the significant other to call the loony bin to come and take you away!

Examine the wires closely for arcing. If you see a blue arc anywhere around the wires you should replace.


(from Benz Repair World)
I smell gas in the morning under the hood…
The first place we used to look on all vehicles equipped with Bosch KE injection is the E.H.A. valve. BTW - that stands for electro hydraulic actuator. The E.H.A. valve is located on the side of the fuel distributor.

First remove the air cleaner assembly. After the air cleaner assembly is removed you will be able to see the fuel distributor. The Mercedes fuel distributor is the size of a Big Mac with a bunch of steel fuel lines coming out of the top of it. On the side of the Mercedes fuel distributor you will see a small black rectangular part, held in by 2 screws, with an electrical connector. That small black rectangular piece is the E.H.A. valve. The valve leaks not the O rings behind it. The valve cannot be repaired and must be replaced.

Also make sure you check every fuel line coming to and from the Mercedes fuel distributor to make sure there are no leaks. You must be extremely careful to take precautions when working with gasoline. Check your Mercedes service manual for the proper procedures for your chassis and Mercedes engine.

(from BenzRepair 8-2004) in this forum
EHA adjustment on older engines
Normal differential pressure on KE-jet engines w/ EHA is .4 bar (5.8PSI); adjusting it slightly higher (.45 bar/ 6.5PSI) will allow for fuel distriburor wear on high-mileage vehicles. I have found that your first time adjusting should be 1/4 turn clockwise; proper adjustment will almost always be right on or within 1/16 turn.you will likely have to readjust the CO mix to compensate.

This link should tell you everything you need to know http://www.peachparts.com/shopforum/showthread.php?t=104289&highlight=adjusting+eha