300e cuts out intermittently
 

This car runs very very smoothly, one cannot hear or feel it idling and power is perfect. Starts fast and clean.
On occasions it will just stall suddenly and cleanly. These events are rare enough, maybe once in three days of normal driving. Most technicians balk at these intermittent faults that seem never to show up when you'd like them to.

What seems a sensible approach to these things. Maybe Merc' diagnostics will show nothing.

Right now I have added 2 cans of fuel line cleaner and will give it a hard run--hoping this may clear a bit of dirt or something transitory.

Would determined servicing of all electrical connections and earth points be useful?

help appreciated

RE: 300e cuts out intermittently
 

Hi, i have a 190e 2.6 auto that started intermittent stalling as if the ignition was switched off. After much testing fault turned out to be Overvoltage Protection Relay.This relay supplies 12v to all the cold start devices and the idle control valve. when the idle control valve looses its supply it does not control tickover and the motor stops. It got continiously worse. I tested for a 12v supply on the red/blue cable onto the idle control valve.On the 190e the relay is situated hid away behind plastic cover behind battery. It is a tall relay with a clear plastic cover and a 10amp fuse in the top of it. Hope this might be of help for you. Mark.

RE: 300e cuts out intermittently
 

hi Mark

Thank you for your response. It will be part of future checks.

Only a week or two after my appeal to Merc' Forum the car stopped after a normal run and would not restart--showing all the symptoms of a flat battery. Tuned out the battery had died suddenly (coincided with our first cooler weather too!)

The battery would not take a charge and the case was bulged longitudinally. The battery had been scrupulously maintained, yet on removal, the 'pregnant' end faces showed that something had gone wrong. It had been in the car 5 years.
Since a new battery was fitted this cutting out has stopped completely.

Following your own observations and experience I was wondering if quite a few intermittent effects are not a consequence of battery deficiencies. It's a subject I'd like to read about more---for example can a working (yet imperfect) battery short or bridge internally to give electrical faults. Maybe its a wise thing to renew a battery that is more than (say) 3 years old if a car is throwing up odd intermittent running problems---so much electronics in modern cars is reliant on this primary power source.

Anyway, your help is appreciated and adds to my roster of possible future solutions.

best

ed

RE: 300e cuts out intermittently
 

Wire short somewhere or a weak ing. coil?