Won't start
 

I have a 1986 300e that had been running perfectly. Several weeks ago I would have problems with it starting after driving it for 5 to 10 minutes then turning it off. Now it is doing it all of the time. The engine cranks over and over and over. It would eventually start prior to this after sitting for a while. Now it just cranks and does not start. Any Ideas what to look for?

Thanks

Temp sensors, idle control valve....crankshaft position sensor.....air meter potentiometer....fuel pumps....fuel pump relay, fuel pressure regulator. Also check the OVP relay.

Its probably one or more of those things.


Based on your specific issues though, I'd suspect fuel pressure regulator or the fuel accumulator....it prevents the fuel from vaporlocking on a hot engine, and preventing starts. Then when it cools it will start again....sounds like your issue. Could also be a fuel pump or pump relay issue.

Does it have spark? If it has spark while cranking its a fuel issue. If no spark then its a sensor issue or a weak coil or bad ignition control unit.