Mercedes-Benz Forum banner

16v high idle problem and microswitch

1K views 2 replies 3 participants last post by  JimSmith 
#1 ·
Ive been trying to diagnose a high idle problem on my 16v. It idles fine when cold but when it reaches normal operating temp, the idle rises to 1400 rpm.
Ive tried replacing the idle valve, air temp sensor with no luck fixing it.
This morning, I tried disconnecting the microswitch and it lowered the idle to normal! Reconnecting the microswitch would cause the idle to rise up again.
It idles better with the microswitch unplugged.
What do you guys think it is?
 
#3 ·
Or spray the microswitch with electrical parts cleaner. Yours is not working. There is a water temperature sensor that also feeds the system that can go bad - one of the items bristling from the thermostat housing blister at the front of the engine. Check the wiring and, if you can find a manual, the resistance readings.

Jim
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top