E-Class (W124) 1984-1995: E 260, E 300, E 320, E 420, E 500 (Includes CE, T, TD models)

Help Please! Idle!!!!

Old Mar 3, 2007 | 05:39 PM
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Unhappy Help Please! Idle!!!!

I've got to get this car to idle higher. Sometimes it's fine in park w/ AC off and it'll idle at about 1000 RPM, once you go into any gear besides park and neutral it drops down to about 500 RPM turn on A/C and it'll drop down to about 400 RPM. Also I was checking around and found this thing to be unplugged? Is there something meant to connect to it? It's getting REALLY annoying and summer will come any day now and with 115oF heat I cannot drive without A/C . Guys PLEASE help!!!!!!!!
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Old Mar 3, 2007 | 06:17 PM
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That "thing" looks pretty important to me. I'm not familiar with the layout of your K-Jet system but that might be the idle air valve which controls the idle speed.
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Old Mar 3, 2007 | 07:14 PM
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Originally Posted by shdoug
That "thing" looks pretty important to me. I'm not familiar with the layout of your K-Jet system but that might be the idle air valve which controls the idle speed.
As in control you mean like if it detects the idle is going down it'll speed it up etc? It looks like any other plug on a W124 but I can't find any random cables laying around near it. I'm gonna go look again to make sure.. Grrr this car is pissing me off! lol
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Old Mar 3, 2007 | 07:33 PM
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Originally Posted by JDW124
As in control you mean like if it detects the idle is going down it'll speed it up etc? It looks like any other plug on a W124 but I can't find any random cables laying around near it. I'm gonna go look again to make sure.. Grrr this car is pissing me off! lol
Look closely as I don't believe your wiring harness fell off. That "thing" is called an idle control valve. Hence it is what the computer adjusts the engine speed with. How long has it been disconnected?
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Old Mar 3, 2007 | 07:46 PM
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From: Bellevue, NE
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Originally Posted by mbenzman
Look closely as I don't believe your wiring harness fell off. That "thing" is called an idle control valve. Hence it is what the computer adjusts the engine speed with. How long has it been disconnected?
Disco!! That's your problem then. This valve controls how much air bypasses the throttle plate during idle, and thus the idle speed. Perhaps when it is disconnected it maintains its current position. On a Ford (forgive me) if you disconnect this valve the engine will immediately cut out or idle so slowly that it is just barely running. On my VW Rabbit (again, apologies) this valve actually had an adjustment on it you could turn to set the minimum airflow position and then lock it down with a jam nut. You've GOT to find that female plug that connects to it and see if that solves the problem.

Can anyone please post a pic of this area on your engine so we can see where the plug is coming from?
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Old Mar 3, 2007 | 08:26 PM
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Well guys, thanks for the help and I found the plug. After looking around I found the exact part laying around, I mean like an extra it was hanging around the engine bay :S plugged in. I took it out and plugged in the idle control valve that was installed and YES it works great now! BUUUUT now the idle will randomly go up to like 3000-4000 RPM when in park or neutral. When I first start it, it starts fine at 1000 RPM but after a while it gradually goes up in RPM's in idle. If I'm driving around it feels like it's pulling me, as in if my brakes go out I'm screwed. I then replaced the current ICV with the extra one that was hanging around in the engine bay and it does the same thing. wtf? THIS CAR HATES ME! LOL
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Old Mar 3, 2007 | 08:30 PM
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someone disconnected the ICV because it wasn't working properly, ghettoooo, anyways, take your ICV out and clean it. It is probably gunked up. Use some wd40 or some brake cleaner to clean it, then make sure it is lubed. That should do it.
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Old Mar 3, 2007 | 08:34 PM
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Originally Posted by myfirstbenz
someone disconnected the ICV because it wasn't working properly, ghettoooo, anyways, take your ICV out and clean it. It is probably gunked up. Use some wd40 or some brake cleaner to clean it, then make sure it is lubed. That should do it.
If it's gunked up would that make it go into high RPM's? And as to clean it I just spray wd40 in there?
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Old Mar 3, 2007 | 08:37 PM
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It could, if this thing gets stuck, it is messing up your air/ fuel mix. spray some wd40 in there move it around and see how well it moves. Should be pretty smooth. It should also be clean bare metal. Look for corrosion etc.

Last edited by myfirstbenz; Mar 3, 2007 at 10:41 PM.
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Old Mar 3, 2007 | 08:41 PM
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Originally Posted by myfirstbenz
It could, if this thing gets stuck, it is messing up your fuel flow. spray some wd40 in there move it around and see how well it moves. Should be pretty smooth. It should also be clean bare metal. Look for corrosion etc.
Thanks for the advice. I'm gonna get to that as soon as I can!
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Old Mar 3, 2007 | 08:58 PM
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I looked into it and on one side theres a slight thin opening, like if it's got a door type of some sort, is that normal? Or is it meant to be wide open on both inlets?
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Old Mar 3, 2007 | 10:24 PM
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Originally Posted by JDW124
I looked into it and on one side theres a slight thin opening, like if it's got a door type of some sort, is that normal? Or is it meant to be wide open on both inlets?


If you would care for every guess in the world I'll be happy to run you around also. So let's see, have you done a search because all answers can be found with the search button on the upper right of the page. Check the air in the tires. Are you too close to power transmission lines, I read that could do strange things including causing brain tumors? (which maybe is my problem) Is your foot on the throttle, removing it should lower the idle it that case? Swapping every part from a known good car might fix it.
Back to my question, how long have you owned this car? (how long has it been disconnected) It controls air (idle air only as the throttle should be completely closed at idle) not fuel. It's controlled by the CIs-E control unit with a ground and the power comes by way of the overvoltage relay. It has to be a severly abused/neglected vehicle to have a sticking idle valve on a m103.
Bottom line, No answers = no answers. I'm sorry it didn't get fixed by plugging it back in, but those plugs don't fall off by themselves. So ask yourself why was it disconnected and maybe you'll be heading somewhere.
Answer some simple questions and we'll try to diagnose you cars ill instead of you just being frustrated.
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Old Mar 3, 2007 | 10:36 PM
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w210 e240
check your deceleration cut off sender at the accelerator cable linkage
aside from your icv
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Old Mar 3, 2007 | 10:39 PM
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Originally Posted by mbenzman
If you would care for every guess in the world I'll be happy to run you around also. So let's see, have you done a search because all answers can be found with the search button on the upper right of the page. Check the air in the tires. Are you too close to power transmission lines, I read that could do strange things including causing brain tumors? (which maybe is my problem) Is your foot on the throttle, removing it should lower the idle it that case? Swapping every part from a known good car might fix it.
Back to my question, how long have you owned this car? (how long has it been disconnected) It controls air (idle air only as the throttle should be completely closed at idle) not fuel. It's controlled by the CIs-E control unit wi.

But I'm not frustrated o_O. And I did search, for adjust, idle, icv and it didn't come up with specific threads. I just asked in my previous post if the ICV is meant to be wide open in the little hose ports, the "out" side seems to be blocked off about 90% is the mechanism meant to freely move?
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Old Mar 3, 2007 | 10:42 PM
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Yeah , the idle control valve will stick. Also, there are two rubber hoses that get old and nasty from being under the hood for long years. They tend to crack and fall apart.

The best thing is to order a new set of hoses and a valve and replace it all at the same time.

The lower or rearward facing hose is time consuming to get installed correctly without a few choice words. At least it was for me.
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Old Mar 3, 2007 | 11:15 PM
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Originally Posted by Don M
Yeah , the idle control valve will stick. Also, there are two rubber hoses that get old and nasty from being under the hood for long years. They tend to crack and fall apart.

The best thing is to order a new set of hoses and a valve and replace it all at the same time.

The lower or rearward facing hose is time consuming to get installed correctly without a few choice words. At least it was for me.
Yep, one of the hoses is all cracked and nasteh. I sometimes forget I have a 17 year old car .

Wanted to thank all you guys for the help and tips, It's much better than before I rather the high RPM's at park than having 20 horses with the A/C on :P
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