91 300ce misses when warmed up - PeachParts Mercedes-Benz Forum

ohiomike · #1 07-06-2007, 10:01 AM

My daughters above car starts missing when warm and about 2000 rpm. New plugs, wires, caps, ovp relay, etc. I wonder if it is sensor that sends water temp to fuel injection system because car feels like it is getting too much gas when this happens. Any ideas...car is nice, always maintained and has 156k on the odometer?

david s poole · #2 07-06-2007, 11:40 AM

that sounds like a good possibility,might also be a leaking eha on side of fuel distributor and finally might be fuel distributor[with those miles it's very common for them to be out of calibration due to accumulation of dirt over the years.

saumil · #3 07-06-2007, 05:01 PM

No misses when it is cold ? Can rev up the engine to high (>5500) rpm without hesitation when cold ?

ohiomike · #4 07-06-2007, 10:10 PM

Well folks, I unplugged the water temperature sensor (C6020-12373) - the 4 prong model and guess what???? no more missing...Thanks for help.

saumil · #5 07-06-2007, 11:12 PM

Two pins are for the fuel injection computer BUT the other two pins are for the auxilary fan. If you also disconnect those two then your auxilary fan will not come on when the engine temp goes high, quite a dangerous situation in summer, so make sure that the sensor is replaced soon. Also if you run without the temp sensor terminal connected, the car may go in a limp mode, will have acceleration problem and warm start problem, so watch for them also.

brabus3.6 · #6 07-08-2007, 12:45 AM

I have exactly the same problem described with my M103 engined brabus. The misfiring/hesitation occurs at 2000rpm, after it the car is fine and pulls with full power as far as I can tell. I assume that the fact that the when the CTS is disconnected there is no hesitation shows that the problem is with the KE-Jetronic system?
My CTS passed the resistance test (between 2.2kohm & 2.8kohm when cold) so could it still be faulty?
I have already replaced and calibrated the airflow potentiometer. My duty cycle measures fixed at 50% which suggests no fault as my car does not have a cat (and so no O2 sensor).