One of my customers, drives a an early 90's 560 slc w/ the 117 engine. anyway he left the lights on and it discharged his battery, so he proceeded with jumping the battery and doing a series with another battery. the problem was he did not notice that he did it REVERSING THE POLARITY. now the car started after they switched it correctly. but it now runs on high idle it runs on 2000+ RPM was this possibly the effect of accidentaly reversing the polarity? any ideas tnx

Could be something got screwed up, but it can also just be that the generator resistance makes the car idle higher until battery power is recovered. Will soon be down to normal if that is the case. Hope for the cheapest...
L.

Check all fuses, especially the one on top of the OVP.

xp

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1985 190E 2.3L - a constant project.

yeah thats what i Thought too., so i replaced the battery with a new one and it still does the same.

xp190 I believe is probably correct. Check the fuse on top of the OVP (overvoltage protection relay). You'll see it back between the dual firewall area, it's a silver relay with a red piece of plastic on top, and also a flip open lid on top. Flip the lid open, there is a red spade type fuse under there, a red 10 amp fuse, I bet it's blown, this will blow if the polarity is reversed. It powers up the engine control module, it's running in fixed operating mode right now, which can give the high idle, poor cold starts, etc.

Gilly

(that is, if it GET's cold in Manila!)