My 89 have very good acceleration in general but when it have been driven like for 1/2 hour or in city traffic which causes the engine to get normally hot,then the acceleration is like down approx. 30%.
I am going to check the o2sensor since that little thing is mentioned a lot.
Could anyone tell me at what temp. the system runs in closed loop.
temp sensor ohm = closed loop ?


Pär Jakobsson
300E 4matic 89 ,240000km

Pelle,

The Temp Sensor at the rear of the head on the drivers side is two sensors in one. Each terminal should read the same resistance to ground cold and hot. If not, it is bad. The coolant temp sensor can be the cause of your ills.

Good luck,

Is the same true for a 190E 2.6? My car will be sluggish when I have been in traffic in hot weather. In the winter the car is fine.

FWIW loss of power with a warmed up engine could be caused by a failed catalytic converter as well.

JDUB,

I expect that you will find the coolant sensor in the same place and the same configuration. It's plenty easy to check with an ohmmeter.

Harry,

Thanks for the thought. It has occurred to me that my Cat could be giving problems, but I did not know that they would flow more when cold.

Have a great day,

I only want to tell that this problem was caused by a bad Coil.

Pelle