Cold Engine Problems
 

1. I have a cold start problem, to overcome it I use to keep my key in ON postion for 5-10 seconds (right before cranking) and it gets started with no problems. WHY IS THIS BEHAVIOUR, what could be faulty??

2. When driving a cold engine (20degrees celcius), the engine doesn't seem to produce a good power and the car is somewhat sluggish until it reaches the operating temprature. WHY???

Thanks
Shams
W124 230E 89

Whats an "W124 230E 89"?
http://catalog.eautopartscatalog.com/mercedesshop/sophio/model.jsp?header=header.jsp&footer=&partner=mercedesshop&baseurl=http://catalog.peachparts.com/&year=1989&make=MB&clientid=mercedesshop&cookieid=1FX0MB1RS1G7186XMP
I guess euro?
Is your ABS light on?
Did you test your Water Temp sensor?

Do a search for the M102 engine, also use 190E as this is the same engine that is in the 190E 2.3 in the US. It is most likely the Water Temp Sensor. That is what tells the CIS-E ECU what the engine temp is so it can en-richen or lean the mixture. Easy to test, do a search as there is lots of info and I have posted the temperature to Ohm readings of that sensor quite a few times. Good Luck.

Yes it is Euro Model: M102
ABS light is not On.
Checked the Temp Sensor, looks bad as it showed 500 Ohms when cold (15-20 degree celcius).

But correct me if I am wrong, water temprature sensor works only at starting the engine but once the engine gets running (even cold) it does not function anymore or does it???

Water temp sensor for KE injection system
Temperature °C........Resistance kΩ
-20........................15.7
-10.........................9.2
0............................5.9
10...........................3.7
20...........................2.5
30...........................1.7
40...........................1.18
50...........................0.84
60...........................0.60
70...........................0.435
80...........................0.325
90...........................0.247
Same resistance values apply to KE intake air temp sensor.
I think this chart applies to these 2 sensors for all KE systems but don't know for sure.

The water temp sensor impells the KE injection to enrich fuel and increase rpm's until opperating temp is reached, to accelerate engine warm up, pervent stalling and increase driveability, so this is likley your problem.
The "cold start valve" is a seperate fuel injector that adds additional fuel on cold starts and does not continue after that.

Marty