My 1990 300CE (I have owned it for 9 months) all of a sudden would not start. My instinct (I have worked on cars for 45+years) was no gas or no spark. I could hear the pump come on and run for 1-2 secs. with ignition on so that seemed o.k. I then removed the distributor/engine cover and checked for spark from one of the distributor cap connections - none. I then pulled the plugs and they smelled of gas. I checked the coil as per the M-B manual and it seemed o.k. but it was old so I replaced it along with the distributor cap and rotor and plugs. Still no spark. I then received the "time-honored" advice from a M-B mechanic - change the overvoltage protection relay: while waiting for the new relay to arrive I checked the old one and found it to be o.k.(this car has the 9-pin setup), but I changed it anyway. Still no spark. I suspect that the ignition module is not functioning. I would like to be able to test the module and the various inputs to the module. A replacement module, used or new, will be bery expensive.