Plugs fouling on MB 450SLC: help!

[Steve P.]

There are a lot of folks here that pull their own wrenches,
so I thought I'd ask for advice here.

My everyday ride (a '73 Mercedes 450 SLC) has started
fouling spark plugs. The strange thing is that they are
being fouled by granular carbon with little or no oil.
Also, its happened on only 3 of the 8 cylenders and the
other plugs look fine (light grey colored insulator).
I've had many LBC's in the past that will foul plugs, but
its usually with a mixture of oil and carbon. Usually
caused by worn rings or valve guides. Thats not the case
with this car.

This car does not have an EGR valve or any smog stuff
(which is one of the reasons I bought it). It is a fuel
injected engine. Could a leaking injector cause this?
How about bad gas? Any suggestions would be greatly
appreciated!

BTW: I do realize there is a Mercedes newsgroup, and have
asked similar technical questions there....the answer is
usually to take it to the dealer. Mercedes owners seem
to have a different mindset! /ubbthreads/images/graemlins/pukeface.gif

 

[sammyb]

I can't remember exactly how that specific Bosch system is set up, but there are a lot of things that can cause that, but I'd isolate the cheap and easy side of the too much fuel, not enough spark mix: bad distributor cap might contribute, bad wires, timing, spark plug gap, weak coil...then go onto FI system parts.