I guess you are talking about to remove the ignition cable from connecting with spark plugs, you just need to pull it out by hand, pls don't hold the cable but to hold the boot (end) and pull it out, same for the both end.
http://mercedesshop.com/Wikka/W201IgnitionSwitch
To remove the ignition lock from a Mercedes-Benz 190E, first, ensure the steering wheel is unlocked and the key is in the "0" position. Remove the plastic cover around the steering column by unscrewing any screws or clips. Next, locate the retaining pin or screw on the ignition lock cylinder, depress it, and gently pull the ignition lock out of the column. Always consult the vehicle’s service manual for specific instructions and safety precautions.
how remove cylinder head
To check the ignition coil on a Mercedes 190E, first, ensure the engine is off and disconnect the negative battery terminal. Remove the ignition coil connector and inspect for any visible damage or corrosion. Use a multimeter to measure the primary and secondary resistance of the coil; the primary should usually be around 0.5 to 1.5 ohms, while the secondary should be around 10,000 to 15,000 ohms. If the readings are outside these ranges, the ignition coil may need to be replaced.
To check the ignition coil on a Mercedes 190E, first ensure the engine is off and disconnect the battery for safety. Remove the ignition coil from the vehicle and use a multimeter to measure the primary and secondary resistance; the primary resistance should typically be around 0.5 to 2 ohms and the secondary resistance should be between 6,000 to 15,000 ohms. If the readings are outside these ranges, the ignition coil may be faulty and should be replaced. Reassemble everything, reconnect the battery, and test the vehicle to confirm proper operation.
A Mercedes 190e doesn't have a carburetor. They are fuel injected.
Maybe brake shift cable from brake to gear shifter?
oil filter on a Mercedes 190E 1986 is in the back of engine
On my 1984 190E, it is simple - there are a couple of tabs at the bottom of the back seat (where your heels would be if you were sittng), you have to look, the seat will pull right out!
Open the bonnet, remove the scuttle cover, wiper motor, and finally blower motor.
On the Mercedes-Benz 190E, the tachometer connections are typically found at the instrument cluster behind the dashboard. The tachometer receives its signal from the ignition system, specifically from the ignition coil or a dedicated tachometer signal wire, which is usually located near the engine compartment. For precise locations, consulting the vehicle's service manual is recommended.
The auxiliary fan on a Mercedes is located in front of the radiator. To remove it, one should remove the wiring connection from the fan first, then unscrew the bolts holding the fan in place.