m103 adjustments fuel economy

[JamesDean]

Hello everyone,

I have a 93 190E 2.6 m103, i am wondering if anyone knows of any adjustments that can be made to the m103 to increase the fuel economy? I adjusted the EHA up a bit ago, I will undo that as I did it under false pretense..I thought it would fix somthing that I unknowningly broke and didnt fix entirely. So aside from setting the EHA back to stock setting..what else can i do?

thanks everyone,

kris

[gmercoleza]

There's not much you can do to tweak any additional economy out of a M103 except for keeping it in perfectly maintained condition including air filter, secondary ignition components, etc. Considering the engine debuted 21 years ago, I think it does pretty well at 18 city / 24 highway (that's what I get in my 300E). A modern Camry 4-banger puts out similar numbers.

If you have the Bosch KE system rather than the later system as found on the M104 engine, you will find a rectangular shaped, plug in resistor in the wiring harness near the master cylinder. This resistor limits the ignition advance and is put in place as a fixed resistance in lieu of a dial which is placed there in Euro delivered cars. The dial changes the resistance, thus changing the maximum ignition advance. This was put there to allow easy change of the maximum ignition advance so that different fuel grades can be compensated for. Removing the resistor gives maximum advance.

You will need to listen closely though, to ensure that you have no pinging.

Good luck,

[david s poole]

worked like a charm on mine.

[rod wimmer]

About 100K miles ago my differential failed on my 103 engine and I bought used one from a google search. Engine rev's a 75 mph dropped to about 2500
and the ABS works intermittently since then but the economy went to 32 mpg highway at 80 mph. The engine has 425K miles on it now and it seems quite content. The engine is turned on for at least two hours per trip and often for 4.5 hours. I dearly love this car.