Hi;

I have a 1987 Mercedes 190e 2.3 8 valve #10298512049789 and since the weather in the northeast turned cold I have noticed that my car when started cold does not go into what I would consider a normal fast idle. It ussually hangs around 1000 rpm and fluctuates +/- 75 RPM until the car warms up. At first I atributed it to the heating of the lambda sensor in the exaust manifold warming up, but I am not sure this is the case. I have checked the air idle valve, replaced the Engine temperature sensor with the two green connections in the cooling system, the EHA Valveo, and the cold start valve. Last night I read that a problem like this can can be caused by a failure in the overvoltage protection relay, and checked the fuse. The fuse was not blown, so now I'm thinking I might have a bad relay. Would the way to check the relay be to keep the fuse removed, start the car, and see if the problem is the same as before, or is it necessary to remove the relay. My next question is 1000 rpm the normal cold start idle speed for this car, and if not do you have any other procedures I might try.

High idle on these cars was roughly 300RPM above warm idle. Warm idle spec is 750RPM for the 190's. So 1000-1100 is normal. Mine does exactly the same. Now my W203 has a higher base idle and fast idle, but that is due to being totally EFI and Drive by Wire, plus for some reason the newer engines need to high idle higher as well as idle higher as I have noticed.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

On cold days does your idle speed vary until the oxygen senor warms up and the ECU kicks in?

A little, maybe +-50 RPM for the first 20-30 seconds.

__________________
~Jamie
_________________
2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....