1990 560SEC Runs fine when cold. When car reaches 80C it starts to run rough and smokes black from exhaust. I just changed the EHA valve and the Overload relay. Previous owner gutted the cat Converter. Could this be part of the problem. Check Engine light is not coming on.


I just went run the car again and noticed it sounded like the electric fuel pump was running continiously I gun the engine a few times and It sound like it stop running got car up to 80C and no black smoke and engine running fine. If I floored the car it will sometimes hesitate blow black smoke and all fine after that. Any help is much appreciated.