1987 300e, Stalls when Hot
 

1987 300e, engine will quit suddenly when temp gauge reaches 100C. The tach needle drops immediatly as if you turned off the key. Recently replaced the following: Fuel pumps ( 2) plus filter, Cap & rotor, all plug wires and new plugs. New coil, replaced fuel relay. This problem usually occurs in stop and go traffic, once on the open road at speed, the temp gauge rarley rises above 80C. I do notice that when the engine is at temp, when I step on the gas hard, the engine will stumble until I back off, not consistantly though.
If I let the car sit with the hood open for approx 10-15 min, it will start fine. No problem with cold starts. Engine runs fine otherwise, no missing, good power.

HELP!!

It might be one of the coolant temperature sensors located near the valve cover.

I've read several times that a bad crankshaft position sensor gives such symptons.
Good luck, Bruno

Is this a DIY job...to check and or replace the sensor?

Thanks

Problem Solved
 

Thanks to Bruno_300TE, my problem is solved. The crankshaft position sensor was the culprit. Relativley easy, but dirty to replace. Car runs smooth and starts crisply.

You learn something every day it seems.

Thanks again to Bruno.

Charles K

300E surges then quits
 

Help!!! I have a german 1985 300 E. They say its the same as 1986 US. Its a 6 cylinder fuel injected. It runs about 20 minutes then starts surging real bad upon acceleration, then it dies, completely everytime you just barely touch the accelerator. It will start right back up but will not move much if you have to press the accelerator. I live in Costa Rica and parts are VERY EXPENSIVE. I have replaced fuel filter, cleaned injectors, replaced fuel pump, and today the (Dosificadora) which is I think the fuel pressure regulator. Its the part that the fuel lines come out of to the injectors. New this part costs here $2000. Rebuilt $1000. I found a used one for $350. but when installed ...nothing ...no change. the mercedes mechanic feels real bad. But ???? I have read here about oxygin sensors, catalytic clogs and crankshaft sensors as being maybe the problem. I can't keep buying parts so really need help on what to do now. Its Friday night and I have an appoinment with my Baby and the mechanix Tuesday. I love this car.
Bill

did you ever find out what the problem was ?

1986 300E crank sensor
 

I found your posts and I have similar symptoms

Which sensor is the culprit Front or rear??

Thank You,
Rich

The diagnostic sign that it is indeed the crankshaft sensor is that revs drop to zero despite the engine still turning. The cable goes from the bell housing at the transmission to the ignition module at the left fender.
Another option could be faulty O2 sensor. It starts to operate with the coolant above a threshold temperature. If it provides false information, the mixture adjustment is screwed up. Or faulty coolant temperature sensor.
Or, the first thing to always check: Rotor, distributor and ignition wires.