coolant temputure sensor
 

I swear that the coolant temp sensor was the issue for my 300TE running issue. I tried several other routes but the coolant temp sensor made all the difference....$35.....plus the good reset of the computer as ohlord prescribed. I was about to goto O2 sensor and fuel pressure but the coolant thing seemed to do it.....I think the ECM wasn't being told the operating temp of the engine and was making bad decisions.....was running way rich..not anymore...maybe keeping the cold start on too long? The old temp sensor was encrusted with white (calcium) gunk so I believe it couldn't acurately sense......what it was supposed to sense...just a guess...cliff

RE: coolant temputure sensor
 

Hey Cliff,

I have had trouble with that sensor too in the past. As it turns out, that sensor is one of the main inputs to the ECM. It's not simply an on/off switch like the aux, fan switch, it is a full range sensor with it's owntemp vs. ohm map. You can test them in hot water with a thermometer and a calibrated ohm meter; I have the map on a CD around here somewhere if you ever need it. You verify the electrical output at about five differnt temperatures, and compare them to the map. A bad one will still give a reading, fooling most people to think it is good, but if the graph sags out of the control limit, it is BAD. It is my understanding that the sensor verifies the function of fuel injection.

The white stuff is likely calcium coming from mixing the coolant with hard-water/mineral rich water. On your next coolant change, make up your coolant with distilled water or used premixed from the dealer, and it will de-calcify your cooling system to a large extent.

Blue

RE: coolant temputure sensor
 

Between this forum and mbworld.org w210 section I am 4 for 4 on the day:D now if I can just figure out that darn vacuum line issue on that guys center air conditioning vent I can rest easy and get some sleep tonight:)
ohlord
You can also back probe those coolant temp sensors and watch the voltage ramp,someplace around here are the ranges.

RE: coolant temputure sensor
 

if ohlord was a major league ball player he'd be have a 5 year $40 million contract...truth...cliff

RE: coolant temputure sensor
 

he's a pro, it shows

Blue