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Discussion Starter #1
Ok, getting a little frustrated here. I replaced my starter a few months ago because it had the typical failure signs. . . click, click, and the car starts, but keeps getting worse. I actually assumed it was the starter solinoid, but thought it best to replace the whole starter while I was at it. The car started fine after that.

Anyways, it is a few months later now and I am havig the same exact problems! Why is my car going through starters? I live in Washington and weather is very mild so no hard starts. Could I have really had a brand new starter fail in the same way as the original? Or, do I potentially have some other problem that is causing my starters to fail or appear to fail?

I remember reading somewhere that these car can have low voltage issues with the ignition system, but I could be wrong. The battery voltage is 12.3+/- which so seems to be ok there.

Any help would be appreciated since I really like this car, but if keeps leaving me stranded I am going to have to get rid of it.
 

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1984 300D
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Connect your Voltmeter to the Battery and have someone else Start the Car and see how far down the Battery Voltage drops.
 

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1984 300D
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Often when people have repeated problems with the Charging (there is other threads; I have replace several alternators and they have all gone bad) or Starting System the poblem is due to corroded wiring or bad connections or grounds.

On Battery Cables if you cut a slit in the insulation by the Terminal Clamps you may find several inches of the Cable is corroded.
On the regular Wiring where the Eyes are crimped onto the wiring Oxidation and corrosion can develop unseen.

There is a way to test for this but I am not sure I can describe it.
I am going to pick the Battery Cable that goes down to the Starter as an example.

It basically as to do with resistance. If there is no resistance in the Cable all of the Electrical Flow/Voltage is going to go through the Cable from the Battery to the Starter.
That measns if the Cable is good if I connect my Volt Meter to the + Battery Terminal and connect the other end of the Volt Meter to the Starter Terminal where that same Cable Attaches and I crank the Starter I should see no Voltage.
So no Voltage during the thest is good.

If I do the same test and I am getting a Voltage reading in the Volt Meter it is because there is resistance in the Cable From the Batter to the Starter.

I am not sure why but resistance causes Amperage to rise and that causes heat.
I am guessing what is happening is that that there is resistance somewhere in the part of the Starter Circuit that Turns the Motor (that includes the Battery Cable and the 2 Ground Cables and even where the Strarter Bolts up to the Bell Housing).
I am guessing that resistance is causing the Contacts to burn up iside of the Starter Solenoid. In the Pic the red arrows point to the 2 contact points.
So while the Contact Points are still new the Starter works OK but as the Contact Points burn the starter does not want to crank.

There is a Ground Strap from the Chassis to the Engine under the Car below where your Feet would rest.
 

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Discussion Starter #4
300Dman,
Thanks for the input. I did some digging through the ingnition system and did find some corrosion on some of the wires and bolts. I replace the bolts and cleaned the wire contracts the best I could. . . let see if this solves the problem.

You also asked about the voltage drop across the battery during startup
Before Start: 12.47 volts
Warming Plugs: 11.55 volts
Starting: 10.5 volts
 
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