Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
I have a 1983 Mercedes 500 SEC V8 where the ignition rotor keeps melting. It is melting according to the picture but not more than that, so I can still drive the car and it runs good. It happened again when I changed to a new rotor. I guess it should not be like this and I would like to troubleshoot. All pictures are in this link:
The ignition system is a traditional rotor distributor and a coil. The ignition trigger is transistorized. See picture from the engine workshop manual. The rotor, distributor and spark plugs are new and the coil seems to be in good condition. I have measured resistance on everything in the ignition system and it is within spec acc to workshop manual. Wires, coil, distributor, spark plugs etc. I have a suspicioun that it could be old ignition cables that is causing the problem. Maybe the spark takes a different route sometimes or build too high energy before release which creates heat that melts the rotor? Maybe too high inductance or shorting to ground?
I have measured on the ignition cable between the coil and distributor with an oscilloscope (picoscope 2204A) with a hantek HT-25 pickup. See the snapshots where the first seems quite normal(?) but the other ones looks like something is wrong.
Topic Author
