Originally posted by ymsin
The engine was last overhauled with pistons and valves change and grind last year. But somehow, carbon still accumalates. Rapid acceleration would blow those carbon away, and after a few successions of acceleration, the carbon built-up is minimal. I only notice this "habit" of carbon building in the W124 260E and wonder if any one else might have a similar "habit".
It defintely requires a good tune-up with the new injectors. The idling has gone way up to 1.1, and thus the engine rev is a little noisy and burning excessive fuel ...
The problems listed above may have been solved with a stroke of a thorough analysis of the engine.
The throttle cable was jammed at one point, and thus the rev was stuck.
Solution: replaced cable. Now the pedal is so much smoother and lighter, and yes, the rpm is back where it should be and the engine sounds very much quieter.
The black smoke could have been due to badly-needed-to-be-replaced air hose which showed signs of extreme wear and tear.
Got that changed too.
Not, the engine performs as good as new and the response immaculate. Black smoke? Don't see that burp coming out now.
I guess, all is well.