190 E Cold Idle

[Placey]

Hello folks.

My 190E will not idle when cold and cuts out, but is OK when warm. Any clues?


Placey
190 E
500 SE

 

[Andy]

Hi

Try checking the overload protection relay fuse. Sited behind the battery & black plastic cover. You will find a silver relay with a red top. Check the fuse there.


Have you jumped started the vehicle recently. This will blow the fuse.


Regards

Andy@ www.mercedesservicing.com

 

[Placey]

Thanks for that Andi - sorry for delay in responding. The fault is intermittent but I shallcheck as suggested.

Cheers



Placey

 

[leicesterboy15]

Hi

I am getting what seems to be the same problem. My car idles but sometimes its rough and when you are on part throttle the car jerks, on full throttle its fine. This happens mainly when its cold but again, its intermittent.

I've changed the fuel filter, dizzy cap, rotor arm (noticed that the actual dizzy was a bit rusty inside), given it a service, checked the HT leads but still no joy.

I think its more obvious now cos theres more moisture in the air. Am I right in thinking its an electrical problem? My rear lights also have a bad earth somewhere and they flash like a Christmas tree when I use one indicator, its a long shot but could they be caused by the same problem, they both surfaced around the same time?

does this sound familiar ?? I will check the relay this weekend.

 

[13022]

Similar (or indeed same!) problem - Car (190E, 1990, at least 181,000 miles and almost certainly much more!) starts first time but idle speed only about 800 revs - even on the coldest day. Whenever you take your foot off the accelerator to brake, the engine cuts out. Apart from that its running perfectly and fine when warmed up.

Just replaced the auxilliary air valve but doesn't seem to be much difference. Replace the temperature sensor - no difference either. Checked the fuse in the relay behind the battery (as per Andy's response above) - thats fine too.

Noticed that the idle microswitch at the end of the throttle cable doesnt seem to have any effect - could this be the culprit or doesn't that switch make a whole load of difference anyway?

Seems as if either (1) car can't detect that its cold or (2) is unable to increase the idle speed when it IS cold.

Any ideas very welcome!

 

[Placey]

A previous problem to the one I have now was similar to the situation above. At idle, the engine would misfire on #1 and be very lumpy but with just a bit of throttle, this disappeared and it ran smooth. Fuel economy suffered badly around town, but not on a long run indicating the misfire was only with low revs. I changed plugs / cap / arm / leads + full service to no avail. Finally, it turned out to be the fuel meter - a very expensive item but it worked and up to now has run perfectly. Everyone who tried to sort it thought it was electrical, but in the end it was a fuel problem. Hope this helps.


Placey
190E
500SE