basafa

I own a 95 S420 for 7 years. About 2 years ago the car sat in the garage for about 5 weeks, when I tried to start the car, it would not start. I charged the battery, the car started but ran rough. When I stopped the car it would not restart. If it sits for a while ( 30 min ), it will restart normal. Surprisingly the check engine light is not on. I took the car to an independent shop they scoped the car and it showed problems with the cruise control actuator, but he was not sure that this was the problem. The car sat till last week. After purchasing a new battery I took the car to another shop. The mechanic tried to restart the car but it would backfired and failed to start. His diagnosis was that the throttle body actuator was bad and the distributor caps and rotors also should be changed. He suggested to also replace the camshaft position sensor. I checked with MBZ dealer and the throttle body actuator is also referred to as cruise control actuator or E-Gas actuator. I have read in the forums that there is a problem with wiring harness in these Mercedes models. How would I know if the problem is the Cruise Control Actuator or the Wiring Harness? Is there diagnostic tools that gives more information than others? Your suggestions and advice are most appreciated.



Thank you in advance,

NZ_Benz

Yea that does sound like the wiring looms/harness, The best way to check is to peel back a bit of the insulation and have a quick look at the wiring some of the stuff might be cracked and brittle that means it's gone.

basafa

Thanks for your quick reply.
How do I check to see if the cruise control actuator is still good?

basafa

Thanks to all for great advice. The mystery problem was the engine wiring harness.

As correctley mentioned by NZ BENZ, this is a common problem for this type of vehicle. In addition, I ended up doing a major tune up including replacing distributor caps, rotors and fuel injection cleaner.

All is left now is to purchase 4 new tires and the car is good to go.

Let’s see what goes wrong next? Hopefully nothing!

Thanks again