Brian McL

I have a 92 400E that acts up when it gets hot. Won't idle smoothly, misses and generally runs rough. I have fixed all the usual problems with this engine ( and few that aren't) like wiring harness, electronic throttle actuator re-build, distributor caps and rotors replaced but can't make the problem go away. I have a snap-on scanner that only gives me one code relating to the crank case postion sensor OR magnets on fly wheel.......both items are fine. I replaced the sensor, but the magnets on the fly wheel are defintely OK. Any ideas?
It only happens when the car is hot......and not all the time. If I stay at highway speed it is fine, but as soon as I slow down it starts to miss. Sometimes if I rev it up in neutral the missing goes away....sometimes it doesn't.
This car has ASR ( and I really wish it didn't) but could that be part of the problem? When I turn the ASR off inside it only stays off (with the little red light on) until 60KPH (36MPH) the turns itself off. Is that normal? Can you only disable the ASR below 35MPH or is there a problem there? Thanks

Brian McL

Problem solved, with a little help from other members. It appears as though the Crankshaft Position Sensor was the culprit after all. The first replacement part by Hella was also defective. Switched it for a MB O.E. part and all is well. The car runs like a dream.
Moral is. when in doubt get it scanned and belive the scanner result.
Oh, and replace the wiring harness anyway.

Brian McL

Oh...and one coil was shot. Very hard to trace.