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1993 e320 coupe
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Discussion Starter #1
I was reading other topics on this site and read an interesting problem on later mercs about under no circumstances should you jump start a merc if you have a flat battery.Apparently it would lead to all sorts of elec problems.
Does this also stand for the w124.
If so what is the correct procedure to take if you get caught with a flat battery.
 

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On the W124 I believe the OVP relay would blow if there was a voltage spike to protect the system.

I wouldn't try it on ANY new fangled Benz. I wouldn't even offer to jump start a wet t-shirt wearing Tyra Banks on the side of a road if I had a newer Benz[:D] She can use my cell phone though[;)]
 

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500E, E320, 190E, E55
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Test and check condition of your batt. monthly..

Jump starting is Ok per owners manual.
Connect ground before positive as always.
 

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2002 SLK32AMG,1995 E320 Cab 1990 300CE(Gone).2002 ML320 (Gone)
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I won't give a jump start with my W124 anymore.
A few years ago I gave a jump start to someone and it wrecked my alarm module ($400+ to fix)
 

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BenzWorld W124 Host
1993 300E 3.2L 24V
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I've given a couple jumps to a handful of damsels in distress with no negative reprecutions.

-Tubs
 

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G320 & E500
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My 300D uses a huge battery. I usually don't feel bad giving others a jump...
When I used to have my '74 240D, I ran the car for a month with no battery at all. I was amazed that I could start that old thing without glow-plugs.

Chuck
 

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1993 e320 coupe
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Discussion Starter #7
Thanks for the input guys.
So we are alright with our 124,s but those unlucky
people with newer merc,s have major probs.
When i read the thread about it i was amazed at all
the problems it can cause.
 

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300TE 4-Matic 300GD
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330 Posts
Hi Biggs.

There are several negative factors to watch out for concerning jump starts. The two most dangerous are ripples and high impedance shocks. These two factors alone are enough to make you want to avoid jumpstarts at all costs.

If you have an old 240D, it doesn't really matter. It will take severe punishments, and still likely work fine. I can testify to some real horrible stories that ended well. On a modern MB with ECU's, CPU's, and CAN buses, it's vital to only use professional startboosters or taking out the battery for reloading. If the owners of these cars were fully aware of the consequenses, they would never ask anyone for a jump start. Here's why.

Let's say you have a 2004 E220 CDI W 211. An old car might or might not produce ripples. If you use another 2004 W211, you will not have any problems with ripples. It produces the same clean current your car needs. Once you have seen the monster water cooled generator in a W 211, you'll know it's a sofisticated thing. But the question of impedance still remains. The shorter the cables, the better. Long cables produce high impedance values, if not corrected by an "impedance swallower" (Help me out here, YAL)

Imagine you have two gas tanks. Tank A is pressurized and tank B not. Each tank has a + and - valve connection. Your task is to connect these following certain rules. When you connect the red hose, you may open the + valve at tank A, but not B. When you connect the black hose, you may open - valve at tank A, but not B. Then you will have pressure in the hoses and tank A, but not tank B. Imagine then that you open the - valve at tank B. Then these tanks will want to equalize the pressure. The result will be gas rushing out of tank A through the black hose. The stream will be high in the beginning, and lower in the end.

This is not a model of how electricity or your batteries work, but it's an attempt to visualize for you what impedance is. The stream of gas can be compared to electrical current which will act similarily.

In the case of the W 211 a collegue can probably help out with short cables and correct procedure, but is it worth the risk?

That's why you should call the MB Mobility Go, or whatever it's called in your country. When I rush out to rescue a stranded MB customer, I use a real high tech start booster, which we modify a lot to satisfy the needs of digitalized modern cars. If that's not possible, take out the battery and take a taxi to a gas station or whatever to reload the battery. In an extreme emergency, I would rather buy a new one. It might pay off very well in the end. Try to inquire about prices on some ECU's and other electronic devices in your car. You'll see what I mean.

Another thing to consider is that the malfunction might appear many months afterwards. Get a Star Diagnosis scan as soon as possible after a jumpstart.

A W 124 is in the border line in my opinion. They do have an OVP. I treat it just like I treat a W 211. Just to be safe and sound. Even though my experience tells me it can take a lot of punishment and still work fine.

Regards

Geir
 

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You hit the nail on the head!

If you want to jump start someone in your post-94 MB do it at your own risk. The cost of those electronic parts alone should be a good enough deterrent but factor in labor and the drooling eyes of your average MB service center as you bring your limping car in should seal it.

Now in a serious emergency...go for it and cross your fingers. Just read up and learn to do it as correctly as you can.
 
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