380SE Erratic idle..help, comments...anything?
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Joined: Aug 2005
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I downgraded to a VW, it's still German though
380SE Erratic idle..help, comments...anything?
My 1984 380 SE is idling crazy. I am having trouble pinning down a cause. Here is what is happening:
engine cold: ~800-1000 RPM in P/N and ~600 in gear.
engine at normal temp (around 80 degrees): ~2000 RPM in P/N, and ~1200 in gear.
engine really hot, (water temp 100+ degrees): ~800 RPM in P/N, and ~600 in gear.
It only gets really hot in heavy traffic with AC on, which is rare where I live. I can't stop anywhere, because putting your car in gear at 2000 RPM is like a clutch drop. You hear everything go CLUNK. I know it is not good for the trans. So if I stop, I am there til the car cools down. Even then, when the engine is cool, and it is warm outside, the engine will might idle high. I have done the tests per Chilton manual, and nothing changes. I suspect one of the temp switches, but am not sure. The tests didn't point in any direction, so probably have multiple things broke. Chilton's sucks for my car, and I have ordered the Mercedes maintenance CD's. Anybody else ever have this idle problem? What about an O2 sensor issue? I am almost going to cry because this is making me insane.
Somebody fabricate me an intake manifold so I can put a carb on this thing. Damn Bosch K systems are all or nothing.
engine cold: ~800-1000 RPM in P/N and ~600 in gear.
engine at normal temp (around 80 degrees): ~2000 RPM in P/N, and ~1200 in gear.
engine really hot, (water temp 100+ degrees): ~800 RPM in P/N, and ~600 in gear.
It only gets really hot in heavy traffic with AC on, which is rare where I live. I can't stop anywhere, because putting your car in gear at 2000 RPM is like a clutch drop. You hear everything go CLUNK. I know it is not good for the trans. So if I stop, I am there til the car cools down. Even then, when the engine is cool, and it is warm outside, the engine will might idle high. I have done the tests per Chilton manual, and nothing changes. I suspect one of the temp switches, but am not sure. The tests didn't point in any direction, so probably have multiple things broke. Chilton's sucks for my car, and I have ordered the Mercedes maintenance CD's. Anybody else ever have this idle problem? What about an O2 sensor issue? I am almost going to cry because this is making me insane.
Somebody fabricate me an intake manifold so I can put a carb on this thing. Damn Bosch K systems are all or nothing.
Thread Starter
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Joined: Aug 2005
Posts: 103
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I downgraded to a VW, it's still German though
I will try that. I hate having to replace it, because I could spend that few hundred bucks on something else like tires. There is no telling, because this car sat for a year before I got it. It was hardly ran during that time.
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Joined: Jan 2004
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From: Florida
85 500 SEL
All the more reason to assume the valve is bad – I hope the soaking works; I had to replace mine – I don’t remember how much I paid for the valve – but the idle stayed at 550 after that.
Thread Starter
Member
Joined: Aug 2005
Posts: 103
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I downgraded to a VW, it's still German though
I cleaned it out with some brake clean, and the inside looked like varnished gas. It idles better, still a little high, but not as erratic. I think replacement is going to be the next step. I thought about taking it apart. I have seen some on eBay for $230, and think MB dealer said $370.
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Member
Joined: Mar 2004
Posts: 109
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From: Orange County, CA
380 SEL 1982
I could be wrong but it should be easy
You will have to remove the air cleaner for better access, but look around at how it is held down and unbolt the old, replace the new.
It turns out that replacing this valve cured my Mustang of its idle woes, and replacing the ignition control box cured the Mercedes.
It turns out that replacing this valve cured my Mustang of its idle woes, and replacing the ignition control box cured the Mercedes.
MBWorld Fanatic!
Joined: May 2005
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From: Chicago
Mercedes
Originally Posted by bcmbcmbcm
You will have to remove the air cleaner for better access, but look around at how it is held down and unbolt the old, replace the new.
It turns out that replacing this valve cured my Mustang of its idle woes, and replacing the ignition control box cured the Mercedes.
It turns out that replacing this valve cured my Mustang of its idle woes, and replacing the ignition control box cured the Mercedes.
Member
Joined: Mar 2004
Posts: 109
Likes: 1
From: Orange County, CA
380 SEL 1982
the ignition control box is on the drivers side fender
under the hood, you are looking right at it. The factory box is a silvery color and rather big. Aftermarket boxes are smaller and usually black. I have been told that if you change the ignition box you should change the coil as well for good measure since a failing box can damage the coil.
MBWorld Fanatic!
Joined: May 2005
Posts: 1,357
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From: Chicago
Mercedes
Originally Posted by bcmbcmbcm
You will have to remove the air cleaner for better access, but look around at how it is held down and unbolt the old, replace the new.
It turns out that replacing this valve cured my Mustang of its idle woes, and replacing the ignition control box cured the Mercedes.
It turns out that replacing this valve cured my Mustang of its idle woes, and replacing the ignition control box cured the Mercedes.
Newbie
Joined: Feb 2007
Posts: 14
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1985 380SE
FYI I replaced the valve and this did not help. Yesterday I replaced the idle control unit and that fixed the problem. I have my old car back. Now if we can just get to the source of those other little nuisances....
