Aight i got this off of www.benzsport.com so i am not to credit for this...This DOES work, i did it as soon as i got home, my car screams now, the pickup is amazing.

Free HP!

Yes, its true, for all the W201 and W124 owners (should be applicable up to at least model year 1993), here is a simple modification that will yield you better throttle response and more power. While researching some other options for upgrading the ignition, I came across some interesting data on the MB service CD. On the Euro spec MB's ignition, there is a item called a reference resistor or R16/1, it is a manually adjustable dial that allows you to retard your ignition timing. On our US spec cars we don't get this wonderful option, but we do have a fixed ohm resister to set out ignition timing. It is a 750 ohm resister which gives us a 6 degree retard in timing. This is standard on all US spec W201's and W124's, its MB answer to the poor, low octane gasoline we have in the US. Now if you are like me and only run high octane 92+ in your car, you can pretty much eliminate the 6 degree of retard altogether. My removing the R16/1 resistor, you in effect end up with no retard. This may be borderline for 92 octane gas, so another option (if you end up experiencing pinging) is to order from MB a R16/1 resistor in 2.4 kohm. This will give you 2 degrees of retard.
So far with no R16/1 resister and 92 octane gas, my 190 is running great with no pinging. The improvement is very noticeable (by my seat of the pants meter). Anyway, if you want to try this on your car I can save you a bit of a headache and tell you where the R16/1 resister is located. On my 1992 190E 2.6, (not sure where its located on the W124 though) it was located by the battery behind the black plastic panel (which is directly behind the battery and hides your ECU and OVP). You should be able to spot it rather easy since it is wrapped in black electrical tape. Once you locate it, just unwrap it and remove the R16/1 resistor, its a small black plastic plug like item with two contacts sticking out of it (MB part number 000 540 24 81). Once removed, you should tape up the wire harness and hide it back behind the black panel. Fill your car up with 92+ octane and enjoy. If you experience pinging or any other strange behavior, you should put the resistor back and see if MB can order you the 2.4 kohm R16/1. Also, on the 16 valve 190Es, the R16/1 is connected to a wire harness coming from the firewall toward the #3 and #4 intake manifold runners, it should be dangling out from the harness and its also wrapped in black electrical tape. Below is the complete chart of values (16 Valve info from the 1986 Service manual and another MB forum).

No resistor = no retard
2.4Kohm resistor = 2 degree retard
1.3Kohm resistor = 4 degree retard
750 ohm resistor = 6 degree retard (standard in US car)
470 ohm resistor = 8 degree retard
220 ohm resistor = 10 degree retard
(part number 000 540 22 81)
0 ohm resistor = 12 degree retard
(part number 000 540 21 81)


Try this at your own risk, I am not responsible for any mishaps or problems you may experience.

I have added some pics of the location on my 201. The harness wrapped in tape is circled in red. The last pic shows what the R16/1 resistor looks like and the part number. Be carefull, on some 190's (the 16 valve) there is a R17 resistor located in this location, make sure you check the number on the resistor before you pull it, the 16 valves R16 is located in another area.

I found the w124 one, look to the left of the brake resivor...It should say 24.81 on it...Might be covered in black tape