Plug fouling 260E
 

Evening guys.
Problem vehicle is a 1987 260E. 98,000 miles believed genuine (yeah right!)
I can put new clean spark plugs in the motor and within 3 mins of idling they are covered in black soot and the motor missfires eventually stalling.
Running rich is my guess.
I've read every thread here (and there's a couple off hundred) with regards to possible reasons. My question is before I start throwing parts at it... what's your best guess'

I will take the most popular guess and run with it:)

Michael

Don't guess, take it to a shop with the correct pressure gauges and check out the fuel distributor pressures.

A failed pressure regulator can do this (if there is gasoline in the hard plastic line going to the rubber breather hose, it's toast), so can a plugged return line, bad fuel pump (inadequate pressure), a bad EHA, or a punctured internal diaphram on the fuel distributor, and even a bad 02 sensor.

Some of this is fairly cheap to replace, some if it very expensive, so it's worth the hour's work to find out.

Peter