98C43AMG

2004 C230K 6speed manual. Wanted to post here since I've read though many threads with no definitive answer, so hopefully this will serve as a future reference for searchers. Go to start the car, click through key positions 1 and 2 and everything works fine, all electronics work as usual, turn to start position and the car starts up fine, runs fine, but everything dies but the motor is running. It's exactly the same as if the key is just placed in the ignition not turned. No power anything. I've searched through many threads only to come up with no actual definitive solution to the problem, couple of the threads just die without an answer. Mostly I've read it could be battery/alternator/key related. I swapped out batteries yesterday (had a spare at full charge) and cleaned all terminals, ground. Runs at 13.6v ish at idle, 14.4v underway. Most of the time after the car has been running for a while the key will work fine, which seems like a low voltage problem. But then other times you can try to restart it after running around and it loses electrical. Both batteries are at 12.76v at rest (100% charge). This has happened on one other occasion when I swapped my key batteries out. I replaced them again Friday and it has been happening again. Not sure what the correlation could be since the ignition sensor needs no batteries to operate, but I'll buy new batteries anyways. I'll probably be ordering a new key at the end of the week. I've tried flipping the key over with no luck, taken the board out and cleaned the inside. For the most part it will fire up every time. Once and a while it will not attempt to start but all power remains on. I just want to post here so future searchers can have an answer.

samaritrey

I would bet money on the EIS as they love to cause strange havoc. I believe I have seen someone with this same/ very similar issue on here before.... no clue how long ago or who posted it though. That said a good once over with a star would be very useful but not using a parts swapper but someone who actually knows the system well and has nothing to gain by swapping 20 parts vs just 1.