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  #1  
Old 01-04-2004, 12:30 PM
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Join Date: Mar 2003
Location: New York
Posts: 101
The 16V idle saga continues

Well, my 16V just like the rest of all the 16V out there shares the same gene of idle blues, stalls, searching idle, stuck at high idle.
Any way, I'm thinking about replacing the Idle control valve and see if it gets better, but before replacing the ICV, I took someone in the forum advice to disconnect the electrical to the ICV. Sure enough the idle is much better, nice and smooth, but guess what, it is so bad when engine is cold, when engine is cold it won't hold idle at all, it just dies. The lesson learned here is the electrical is there for a reason, you don't just cut it off and leave it hang like that and walk away with a smiley face, you will pay baby!
So, should I go for it and replace the ICV, it is a bit expensive but I will replace it if it help cure my stalling problem.
Alex

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  #2  
Old 01-04-2004, 09:23 PM
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Join Date: Dec 2003
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16valex,
When I purchased by 16v it to had the idle up blues. However mine was simply the idle/full contact switch not completing the idle connection. When the car was hot and surging I bypassed the switch. Then having the throttle valve off the car I sprayed some Wurth electronic gizmo cleaner on the switch and set the adj towards the idle side with an ohmmeter. The engine has idled perfect for 3 years. And do not get confused because it is the switch you cannot see, but the three prong connector you can see. The switch is only available with the throttle housing thru MBUSA but somewhere this Bosch switch must be available.
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Old 01-05-2004, 05:42 PM
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Paulwho,

I did check the throttle full contact switch by way of Ohming at the three prongs connector between the midle pin and the far sided pin, they seem to toggle as I open and close the throttle valve. I also checked the idle micro switch, and this works too.

Does any one knows a way to check the ICV???

Thank you for your help
Alex
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  #4  
Old 01-05-2004, 06:27 PM
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Look at it this way - if removing electrical input to the ICV allows a smooth idle at a consistent rpm, then mechnically it is returning properly to rest. Also, it likely is operating smoothly around that point as well.

The ICV is controlled by the idle control circuit of the ECU, and any of several inputs to the ECU can tell it it needs to modify the position of the ICV. This is causing your variable idle, and some sensor is probably the culprit, or the sensor is properly reading an incorrect condition, and the ECU is trying to compensate by varying the idle. Either way, I would look at the input sensors:

-temp sensors
-oxygen sensor
-air flow meter potentiometer

etc.

Steve
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  #5  
Old 01-05-2004, 07:16 PM
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Join Date: Mar 2003
Location: New York
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Sbourg,

So, I take it that is nothing wrong with the ICV!! The ICV does what the the ECU is telling to do.

The temperature sensor is brand new. The AF potentiometer is good, I looked at it, and there is no defect that the eye can see. I also placed the potentiometer where it read 400mv, between pin 1 and 2 ignition on engine off. The car starts every time, cold or hot, runs very good thru out the whole range, no miss whatsoever, not bad for a 208,000 miles!!! ( knock on wood)

You have mentioned about the O2 sensor, this could be the culprit, I have not replaced it in ten years of my ownership. I would like to disconnect the O2 sensor and see how the idle would behave. Would you happen to know where this O2 sensor connector is???
Thanks in advance
Alex
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  #6  
Old 01-10-2004, 03:17 PM
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Join Date: Apr 2002
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Just curious, but where and what is the throttle full contact switch? My idle fluctuates when warm on my 16v, no problems when cold, but I do know that my oxygen sensor is bad so I am replacing it. Hopefully that will fix my problem. My car also never dies at idle, the idle just simply jumps around a little.
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  #7  
Old 01-10-2004, 05:24 PM
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Location: Southern California
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The idle/WOT switch is on the end of the throttle shaft under the fuel distributor. It is difficult to reach, but has a three lead pigtail (idle, WOT, and ground) that you can disconnect at the harness connector to test the switch for function. Also check the linkage microswitch for proper function,

If the Idle contact on the throttle switch or microswitch is not functioning properly or consistently, the ECU will not know that the car is at idle and will not send the proper commands to the ISV to maintain a stable idle speed.

Duke

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