Mechanics

MERCEDES

1989 Mercedes Benz 300se • 6 cylinder 2WD Automatic • 155,000 miles

Engine turns over but will not start all the time. Sometimes it will start right away. May drive 1/4 of a mile then stop and then it is hard to start again. After driving for 7or8 miles will usually start the rest of the day. Help?
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Woodford
January 8, 2011.



Next time it refuses to start don't wait for it to make up its mind-do below immediately to determine if its fuel or spark problem

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if okay-check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs, coil's resistances, cap and rotor, distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it and keep testing.

Rasmataz
Mar 14, 2011.