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Discussion Starter #1
My 87 300e, wont start. It acts like the battery needs jumped, but battery is at 12v. It will start when I jump it, I can drive it from home to work (about 15mi) with no probs. When I shut it off, I'll try to start it up again, and it wont start. It acts like its tryin, but wont fully turn over. your input is greatly appreciated.
Thanks
 

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03 E320 4M Wagon & 97 E320
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You need a new battery.

You can go to an autoparts store to have the battery load tested.

A battery that measures 12 V does not mean it can provide enough current to run the starter. Actually if you measure the voltage while cranking, its voltage will drop probably by a lot.
 

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W124 92 260E
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Get the alternator checks as well. It could be the alternator that going bad that doesn't charge the battery.
 

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86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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In lieu of a new alternator, a common failure is the voltage regulator. The part is less than $40 at NAPA, is located on the back of the alternator and can be changed out with a phillips head screw driver. There is no need to remove the alternator to do this. It can be done in the parking lot. Two screws hold it on.

Good Luck,

Jayare
 

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Discussion Starter #6
it is a mercedes battery, looks fresh. I have only had this for a year. I have swapped the altenator, about 8 mos. ago.
 

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Discussion Starter #7
I tried a different battery, jumped it let it run for 15min. Turned it off. Went to start it up...CLICK. Any suggestions?
 

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03 E320 4M Wagon & 97 E320
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scott87300e said:
I tried a different battery, jumped it let it run for 15min. Turned it off. Went to start it up...CLICK. Any suggestions?
Is that a new battery? I guess not because you would not need to jump it with a new battery.

Do you kow that is a good battery?

Try to give more detailed and accurate information in your short posts so people can help you.

The car runs after jumping. That means the alternator/voltage regulator are working. You cannot start the car so it is either the battery or your starter is failing (requires a lot of current, more than spec.)

You can further test the alternator/voltage regulator by measuring the voltage on the battery when the car runs. It should be around 14 V with a good charging system.
 

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scott87300e said:
it is a mercedes battery, looks fresh. I have only had this for a year. I have swapped the altenator, about 8 mos. ago.
Do you mean you had the battery for a year or car for a year? If car, then it does not make any difference how fresh the battery looks to you.

As I said in an earlier post, you need to provide better information.
 

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Discussion Starter #10
The voltage when running was mid 14.
Only had the car for a year. So no I dont know, how old the battery is. I am not sure that the battery I just tried was good, got it from a friend. Should I put my mercedes battery on a battery charger?
 

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'84 300D/ dakota benz trk. Sold... miss it. "88 260E '91 190E 2.6 '89 Volvo 240DL "85 300D
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buy a new "quality" battery. period. if your old batts were crap and the car ran fine once started, then it sounds like your charging system is FMC. if NEW batt. does not fix it, then you would need a new starter. however, if the starter was trying to go inop, it would act funny even with 14+ volts going to it. i have seen batts many times test 12v+ until you applied load, then they would go to 5-7 volts. happens all the time.
 

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Discussion Starter #12
I will try a new battery. One more thing. When I jumped it, there was a ticking, its speed increased with gas. I dont know if this could cause, it to not start. Thanks
 
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