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Engine suddenly started idling at 2500 rpm - Help!

2K views 7 replies 5 participants last post by  Thguns 
#1 ·
Hi guys,

Need a quick bit of help on my '83 380SEC . I did a 200 mile jaunt today, but suddenly on the way home, the engine started to idle really fast. I have disconnected the linkage, and it didn't drop back down, so I guess it is something non-mechanical. The only clue that I can give is that the temperature guage had never previously worked, but suddenly started to play when the idle problem occured.
Although it is an '83, I can confirm that it has the electronic idle unit.

Any ideas would be most appriciated?
 
#2 ·
This might not apply, but does your car, of that year, use ABS?
Mine is an 89 560sel and has ABS. Sometimes the ABS warning light lights up and the engine starts idling at 2500 rpm. I can't figure out the source of the problem since the ABS for the most part works (of course maybe not when it the warning light is on).
 
#6 ·
It turned out to be the relay that controls the idle valve. On a left drive car, this is an easy sway-out as it sits in between the two firewall, but on my right hand drive car, it's tucked up under the dash. [8)]
I've got around the problem for now by manually controlling the idle valve - Well actually replacing the electronic one with a screw-tap. It works OK, but of course it doesn't compensate for cold starts, so but will have to crawl under dash in the next week or so...

Thanks again for your help.
 
#7 ·
Idle control Unit for sure, mine change with new one everything back to notmal 500 rpm. BUT make sure you drain out your water radiator, DO NOT USE other coolant for your benz, it will not cool your engine temperature.. Use coolant design by MB with benz emblem..I owned 380SE.. [:)]
 
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