I don't know what the sensor in the middle is, mine doesn't have one & is plugged off. The blue one nearest the head is the temp sensor for fuel mixture input. The one furthest from the head is for the instrument temp gauge. The older 80's version Motronic for the big six used a cold-start injector which was basically a 7th injector plugged into the manifold to enrich the mixture. Our e32's have that function built into the new version Motronic & eliminated the cold-start injector.

The sensor should read 2.1 to 2.9 k-ohms cold (68F) and 270 to 400 ohms warm (176F), ref. Bentley's pg. 130-15. Mine reads 250 ohms warm, a little low but not enough to get excited about. There was a BMW repair bulletin with a part number as well, for the 6 series which consisted of cutting & splicing the brown/violet wire & inserting a 270 ohm resistor in series to increase the resistance to "trick" the DME into running a little richer which benefitted by smoothing the idle. I don't know if the added resistance would affect the mixture thru-out the throttle range besides idle. It would be simple enough to play with different resistor values, I would think a 1/4 or 1/2 watt resistor would be more than sufficient.

If you verify your sensor is within range, check for a vacuum leak(s).

Also, mine has another sensor near cyl. 6 on the intake manifold side. I do not know what its function is. Anybody?

gale
92 735i

Could someone explain to me what is the function of the EML
coolant temperature sensor. My car has 3 little sensors coming from the thermostat housing which by bentley are the
temp gauge sender, engine coolant temp sensor and the EML coolant temp sensor. My car is running a little rough at idle. I have read that the possible problems can be one these sensors. TIA..

'92 735I 78K