An 84 190E would have the Standard Version of the K-Jetronic Fuel Injection System. You can make all the adjustments you want on this.
There is a Tower which takes a 3mm Allen Key inside the air filter housing, this is where you adjust the fuel mixture.
While you're adjusting that, you may also want to check the Ignition Timing.
The best way to make the fuel mixture adjustment is by using an analog meter, and hook it up between pin 3 and 6, that way you can watch the ossilations of the 02 sensor and make the adjustments accordingly