I need some suggestions from some of the experts out there. In addition to my crossfire, I also own a 1975 Mercedes 450 SL. About two months ago, one day it decided to no longer stay running and blow black soot (very rich). Obviously the plugs became quickly fouled and it became very hard to start. This was sudden and there was no deterioration in performance, along the way. This was (is) a restored, low usage vehicle. I have since replaced the cold start switch, all of the injectors, the coil, tune up including wires, replaced all of the vacuum lines I could see and replaced some regular wires that looked questionable. I can now get it to start and run but only at a very high idle. When I put it in gear, it dies. I also can not set the timing at TDC, 20-25 degrees advanced is about it without it stalling.
Does anyone have a solution or suggestion on where I might go from here? Are any of you gear heads into older Mercedes or just full of mechanical knowledge??? HELP, HELP HELP !!!

 

still getting black soot exhaust from your Mercedes after changing what you changed? how about the fuel pump, filter, MAF/MAP, etc? i'm guessing its fuel injected by you saying you did the injectors. maybe the computer? an overly rich mixture won't affect your performance that much. it will however foul up your plugs and your cat, and cause a load of black soot.

 

Strange that you can't set the timing to specs. Dual overhead cams, right?

 

Have you gone through the fuel system, including the gas tank. Sludge/shellac is a killer.