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Discussion Starter #1
newb here:)

i just bought a 87 e300. the car is in very nice shape and me being a car guy i just couldnt say no. lol. my problem is the guy told my that he thinks the charging system doesnt work on it. he said the battery is brand new and the alternator isnt that old. i think he said a year old.

i let it sit for about a week now and i went to start it today and it cranked a few but didnt have enoough ass to fire. then died...

so im assuming something is pulling juice from the battery.

i did a little reading on what are good things to replace on these cars. just in the little reading i have done.. i came up with ...

*replacing fuses
*replacing the "OVP"??
*new fuel pump replay

thats all i have have seem to read.

any info or ideas are greatfully appreciated

thanks
 

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W124
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Couple of questions

You have some conflicting information in your post. How can it not have enough "ass"(?) to fire but also die?
 

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Discussion Starter #3
since the battery was practicaly dead... it only turned over a few times. then there was nothing. there was no battery life left to even get it to turn over.

sorry about the confusion
 

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1998 E300, 2006 R350
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You say you had let it sit for a week. Did it run before that? If it did, charge the battery, then load test it to verify that it's good, and start from there. It's hard to diagnose the symptoms of a car with a dead battery.
 

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Discussion Starter #5
You say you had let it sit for a week. Did it run before that? If it did, charge the battery, then load test it to verify that it's good, and start from there. It's hard to diagnose the symptoms of a car with a dead battery.


yes.. it did run before i let it sit. i have the battery out now and gonna charge it tomorrow. ill let u know what happens when i put it back in.

thanks for the replys everyone.
 

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91 500SL 37k,90 300SE sold, 91 300E sold , 92 300E137k ,02 Kia Sedona ,I know..... its a Mini van.
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You have to test the battery cells,there is a tool,or charge you battery ,and take it to Autozone ,where they will test battery with a device that simulates a load,and you can see the needle move! remember if you start the car and test voltage at battery with lights on,it should be around 13 to 14 volts DC,if it does,alternator is good.if after 4 hrs car wont start ,replace battery
 

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Discussion Starter #8
update..

charged the battery. and took it to autozone and they put a load test on it. it passed pefectly. which i figured it would of.


i got back home, hooked the battery up and attached my voltmeter to the pos and neg of the battery.

it read 12.38v

i started the car. fired right up, which i figured it would.

while it was running, i got out and looked at voltmeter. it still sat at 12.3x volts.

now to me.. i expect the alternator isnt charging the battery while driving. i was expecting more like 14volts, on the battery.

so i pulled out the hanes book and it said it should be around 12-13v. but i still think the alternator is bad.

any ideas??
 

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1988 300E
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I have the same Benz(an '88 tho) & had a similar problem...if I let it sit for a few days the battery would be dead. I started looking for the 'drainer', I found it to be an after-market alarm system the previous owner had installed. Oddly, it took 8 years for this part to crap-out!
So: I'd check for any 'added' parts & check any obvious loose wiring...particularly ground wires.

Regards

ps: I'm not much of a 'wrench', so the above comment may be a total waste of time...but it worked for me.
 

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'95 E300 DIESEL, '91 600SEL, '92 600SEL
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98% chance it's the voltage regulator that is the problem. No need to replace the alternator if only the internal regulator is bad.
 
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