My 1986 300E has a fuel problem. I bought it recently with a fried fuel pump relay ( the connectors were melted ) and some nasty old gas in the tank.
I replaced the fuel pump and the relay after soldering a new connector plug for the relay. I also installed a new fuel filter and put fresh gas in the tank after draining out the old. The car ran fine for about two weeks then all of a sudden the car would stall out and not restart. i pulled a spark plug to check condition and spark, the plugs were black indicating a possible too rich fuel mixture ?, I changed out the plugs and the car started and idled fine for about 10 minutes then began to sputter and stall out. I tried to start the car again, it started and idled fine but when I went to give it some gas it cut out quick.
Any suggestions?

Hi

just solved a stalling problem on a 190E(very similar car with the same systems).

I checked all the electricial components in the engine compartment related to the fuel system. Then I checked the wiring harness and connection to control module. After those checked out I tested both fuel pumps and they checked out. I took a closer look at the plastic cover and noticed that there was a leak at the hoses at the fuel pump assembly. I bought all new hoses, replaced the in line filter in the gas tank, cheked the suge bowl in the tank, the OVP and mas( your model year wont have it).

The problem was still present until I replaced the hoses at the fuel pump assembly and the car has been running fine since.

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1986 300SDL, 211K,Dealership serviced its whole life
1991 190E 2.6(120k)
1983 300D(300k)
1977 300D(211k)

I will check the hoses out first thing to eliminate that possibility.
Thanks!

I checked the hoses out (the ones around the fuel pump and filter) and they seem to be fine, no leaks or cracks or loose connections.