89 200 quattro oil Check Engine with Buzzer.

[FLORENTCAT@aol.com]

Hi.
On my 200 Quattro the oil pressure gauge stop working and the oil light at the
Check engine was coming on at 3000 RPM. 
My mechanic change the oil switch sensor, this solve the oil pressure gauge,
but I still had the problem with the oil light and Buzzer when reaching 3000
RPM. 
My mechanic said there is nothing wrong with the oil pressure, He does not
know exactly why at 3000 RPM the light and buzzer are going off, He suggested
to ground a wire from the oil sensor to stop this fault for now.
 I did it and at 3000 RPM the light and buzzer do not come on.
Does anybody know what is going on, am I going to fry the engine, although the
oil pressure gauge work correctly. I am a new subscriber to the club, do you
have this in some archives?  
Thanks
Florent

89 200 quattro
84 5000s