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W210 Wont rev over 1k

8971 Views 20 Replies 6 Participants Last post by  icy75
I went to start my car yesterday and all I got was a single click, I presumed it was a dead battery (battery is about 3 months old) car is not used much, when I took the battery off the earth terminal was wet and rusty, in fact the nut has rotted away the terminal pulls on and off the pole with slight force, I dried the pole charged the battery overnight, I put the battery on this morning and I still just get a click, I know the battery is fully charged and is healthy, if the battery was faulty my charger would tell me.

Where is the moisture coming from on the negative terminal nothing else is wet?

I have replaced the earth strap, the old one was a mess, there is nothing else under the seat that was damp just the earth terminal.

The car now starts perfectly fine with the first turn of the key since changing the earth strap, however a new problem has manifested in that I have absolutely no power whether it be forward reverse 1 or 2, on tick-over it isn't steady and rapidly rises and falls, if I put my foot on the accelerator I get a miniscule response, I do have a 38 pin fault code reader which didn't pick up anything.
When I last moved the car about a week ago it was running very smooth it seems strange that suddenly after the battery incident the car has thrown its teddy out of the pram and stubbornly refuses to move.

I have had BAS/ESP & SRS lights on for a while which I was going to get reset this week or see if there's any problems if it wont reset, but today since putting the battery back on I suddenly have anti skid warning flash up on dash as well as the ABS warning on screen (the car wasn't moving )

The car wont accelerate past 1k revs which made it interesting as I had already rolled off the drive ok in reverse before discovering this fault and was then stuck across the middle of the road and the car could literally move a few milimetres on its own steam.

I have had lots of cars before in fact this is my 40th car and have never seen any with problems such as with this car, I will never buy another Mercedes again once I finally manage to get rid of this one.
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1 - 5 of 21 Posts
Those light also come at low car voltage. That should be easy to check.
How old are your alternator brushes?
You need to slow down and do step by step. This is computerized car and messing with interlocking systems in 3 points at the same time can create chaos only.
First the cable shows acid marks on it, what could be indication of overcharge. You never check the car voltage and this is second indication that something might be wrong with the charging system.
It might be overkill to take the car to Star computer to read the voltage.
How about checking it on the clima display or with multimeter?
US models can display sensor values on climatization LCD.
I know UK models don't always have the LCD, in which case you need multimeter.
I would make a hookup via cigarette lighter socket so you can observe it during driving.
The way the overcharged battery work is that during charging it releases corrosive gases via caps and that is what condensate on battery clamps.
I have the issue on my tractor where I have to clean the clamps couple times a year. Putting just few hr on it every year, I am not going to replace the alternator.
This way or the other we can talk forever what 3 seconds spend on checking the car voltage will reveal.
Above 14V is overcharge. I would replace voltage regulator if that voltage stays during driving.
Don't think German let British to drive on fumes, so the batteries have to be vented outside.
1 - 5 of 21 Posts
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