Thanks to Steve, he led me in the right direction as I was thinking I needed a tach sending unit and a reference sensor. Apparently that is for diesel cars and I didn't pick that up when reading the forums. Since I didn't need those, I found this green wire coming from the distrubuter and going to a part on the left fendor that it plugs into like an rca jack. From there there was a connector going to the coil, and some wires went to the coil, and another to another part on the left fendor. I decided to try to hook to this other part (it has a round screw on cap with a connector with 9 pins - maybe for diagnostics?) where that wires goes, and VOILA, the tach works perfectly!! Yeeeha!!

Next problem was my idle speed being too high. I read alot on this forum and people were talking about an idle valve. I looked in performance products and I can't find this guy in my car. I have a 1983 european Mercedes so it may be different than the 84 US version the catalog is talking about. What I did find was a screw that is accessable from the center of the valve cover and right below the air cleaner housing. I turned that screw 3 turns and my fast idle dropped from 1250 rpms to about 750 rpms. I set the idle so the oil pressure guage was at 2.1 or so (used to be pegged at 3) and with headlights on it drops to 2. I seem to remember years ago, when the car was hot in the summer at idle the oil pressure was at 1.5. Since it is winter and the oil is colder hence more pressure, I set it to 2.1 and with 750 rpms as I would expect to be right.

Can someone comment on if what I did was right or wrong? I mean I know you should not be turning screws and should be replacing bad parts like the idle valve or something else, but its possible that some mechanic turned this screw in the past and make the idle faster. Its been fast like this for as long as I can remember. Just happy to see it as you guys say now (750 rpms) for a 190e.

Thanks to all!!

-=>Raja.

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1983 MB 190E, bought from Germany and shipped to the US in 1986.