How to test your coolant temperature sensors

Another off the cuff video on testing your coolant temperature sensors in your e30 and other models

[ammefan]

This might be a long shot, but.... My 1992 OBD1 E36 325i has had this idle and fuel consumtion issue for years. Idle sounds and feels perfect when cold, but when it gets just a little warm the idle seems... off. My brother couldn't notice it but there definitely is a difference. Erratic engine vibrations, slight audible rpm fluctuations. And also consumes a ton of fuel, like 18 mpg pure city driving on a good week. 38 mpg is the best I've gotten on highway.
Replaced 2 O2 sensors in the last 5 years, tried another mass airflow sensor, replaced the throttle position sensor, ignition coils, spark plugs, valve cover gasket, intake manifold gaskets, cam + crank position sensors, tried cleaning idle control valve. I hoped the coils would do the trick as all 6 were expensive, but nothing changed the rough idle and high fuel consumption (Though I suspect the transmission needs an oil change) Also, probably no vacuum leaks, I fixed one leak that did nothing to the idle and poor mileage.

The car seems to have plenty of power, though.
I really want to make it idle as perfectly when it's warm as it does when cold. Also the exhaust smells rich.

Tons of reading have lead me to believe that the blue coolant temp sensor (the ECU one, I think) might be the problem. Maybe knock sensor? I even bought INPA/Ediabas and an old laptop with native serial port, but couldn't get that to work. Hoping someone can help.

[IntuitiveJohn]

Could you please tell me the name of the gauge rebuilder is...couldn't hear it clearly...Many Thanks Very useful

[LifeWideOpen]

Love the videos, keep up the good work. Ps you look like a Disney character

[monster]

I recently bought a 1985 325e 2.7 i6
And it doesn’t start. It only turns on with starter fluid. Once the cars on and warms up it’ll turn on on it’s own. Both fuel pumps have been replaced, spark plug wires, coolant temp sensor, fuel filter, I also did a oil change plug oil filter change, the injectors are 42lb injectors not sure when they were replaced . I also did a compression test and all cylinders were 150-160 other then 1 which was at 135 .. I have fuel and I have spark. Not sure why it won’t start on its own. It’s also turbo charged. Any help?

[thomasposeyunknownhero]

Hey question for you, I found a big vacuum leak with the tps o-ring. Switched that out and car now has steady 800rpm idle. But shakes and idles harsh. Had a walking idle before vacuum fix, and always felt like a misfire. Still feels like a misfire but I don’t know what to test next

[farhadhoseinpour]

Hello, this could be a nice and useful video, but would you please show the item and engin and workstation table instead of fix camera on your face???