190e Coolant Temp Sensor - Cold Starting
 

How does the coolant temperature sensor effect cold starting?
How can it cause the engine to start hard when cold?
I have an 88 190e 2.3

The coolant temp sensor tells the ECU how cold it is, so the ECU can richen up your fuel mixture accordingly.
This replaces the " choke " of yesteryear.
If the sensor does not function properly ( indicating a warm engine ) the fuel mixture would be lean.
Hope this helps. ;)

Rather than start a new thread I'll revive this one from the dead.

My euro 2.0 ltr has this type of sensor but black not green.

http://img.eautopartscatalog.com/live/C602012903BOS.JPG

How do I measure if its working correctly? (I have starting issues and am looking to go through the system before replacing anything.)

Mike.

Time for the resistence check...
 

Properly reset your handy ohm meter to zero;

Unplug the wire plug-ins on this coolant temp sensor...

On an unheated engine ohm resistence should read approximately 2,000 ohms...

After the engine is fully warmed up new resistence readings should be around 200 ohms...

Generaly speaking the over voltage protection OVP should be considered suspect/faulty before the coolant temp device...

Just trying to help thanks.

:) Machnumber2 i have the same problem, but mine is a 300e. i have been to 3 different (MB Specialist)mechanics but they couldnt solve my cold start problem. i spend thousands changing parts that didnt solved the problem(fuel filter,OVP, cold start relay, plugs & wires. fuel pump relay....etc. they even want to change my cat and fuel pump. so iwent to my mechanic for my van(which is not an MB specialist). he said all i need is a coolant temp. sensor. iam gonna get the parts tommorow so i'll let you know. coz i know i how frustrating it is spending money on uneccessary parts.

they just put my new coolant temperature sensor, no luck i thought that would fix my cold start problem. but it help the starting a bit now the most i have to crank it is twice. sometimes i just want to give up fixing it. ill do more research.