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#1
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1984 380SE 126 Idle Control Valve
The idle on this car is 1100 then after giving it some gas it the idle races. Putitn git in gear is a bit scary because of the idle speed.
The Idle control box looks really clean inside and appears to have no corrosion on the connectors. If I disconnect the connector from the valve nothing happens and there is no change in the idle. I was not able to soak the valve overnight but alot of carbon came out of it when I hosed it down with carb cleaner. It appears as if it is stuck open as I could see the slot from the side opening was not closed but I am assuming that it should be if there is no power being applied to the valve. Is this correct? I know this subject has been talked about alot but I didn't see anything that explained how this unit operates.
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MB 72 250 M130.923 114.011 170k The Beauty |
#2
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The one my 190 uses is open when de-energized. I verified the mechanism was working correctly by bench testing it.
Steve |
#3
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Pull the connector part way off the valve, connect a DMM to each pin and measure the voltage. I suspect you will see 0, which indicates a faulty idle control unit. Meaning that no voltage is allowing the valve to sit wide open thus max idle.
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Chuck Taylor Falls Church VA '66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe |
#4
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gmask,
The idle speed control module will look completely normal even if it is bad. I'm a computer engineer, and I couldn't see the bad solder joints. The cheapest fix for you is to get a radio shack soldering iron and some fine solder and get each dot of solder melted on the board with just a little fresh solder. Make sure your solder has a rosin core, as this will help it clean out the corrosion. I did a complete description on the board a while back. You might try searching for it with "solder idle speed control". |
#5
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Quote:
As per the previous post the valve appears to be stuck open or is it normally open when no power is applied?
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MB 72 250 M130.923 114.011 170k The Beauty |
#6
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Digital Multi-Meter (but analog is OK). No power is wide open, I think.
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Chuck Taylor Falls Church VA '66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe |
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