# really high idle issue



## neocracysk8 (Jun 26, 2012)

My car idles around 2000 rpm it is a 1.8 8v Cis. It idles at 2000 rpm and then drops down to normal driving speed when I start to drive. I was told to check the vacuum lines. But I was wondering if anyone else has had this issue and if they know what the problem is??


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## dasautovdub420 (May 10, 2012)

I had the same problem with my MK3 1.8 8v, but only when it was under -5 degrees, although mine only idled just above 1,000RPM's. Not sure if your car has IACV (Idle air control valve) but check that if anything.


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## neocracysk8 (Jun 26, 2012)

im not sure all i know is its cis injection and i talked to a guy and he said that he recommends redoing all of the vacuum hoses.


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## Fat Rabbit (Nov 18, 2001)

You for sure need to check for vacuum leaks. It is a common issue. Sometimes you can hear them. Inspect all around the engine. There are numerous potential sources for air leaks in addition to vacuum hoses but the small hoses are a good place to start. Usually just the woven covered ends of the hoses need to be replaced. The hose rubber rots out internally and the woven covering on the outside hides the holes. 

I trust that you are asking about your 8V '86 GTI. That car has an ISV. It sits near the valve cover. A quick check is to listen for it humming with the key on. You could also place your hand on it to see if it is vibrating -- once again with the key on. Other potential air leak sources on that car: injector "O" rings, the rubber hose connectors to the ISV, the rubber elbow for the hose from the ISV to the intake manifold, check the rubber intake boot from the fuel distributor to the throttle body carefully for cracks, the rubber "O" ring gasket where the hoses connect on top of the cylinder head cover and last but not least check the rubber hose that runs from the intake boot to a flange behind the cylinder head cover between cylinders 3 & 4 (that flange also has a gasket underneath it that can go bad. FR


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## neocracysk8 (Jun 26, 2012)

whats an ISV? and yes i am talking about my 8v gti. thanks you so much. im gonna try and look at it this weekend. if i cant find anything then i know a car that works at a vw place as a technician. i might have him swing on by my house and see what he can figure out.


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## Fat Rabbit (Nov 18, 2001)

ISV = Idle Stabilizer Valve FR


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## neocracysk8 (Jun 26, 2012)

thank you. i will be sure to let you know how it turns out.


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## in5ane (Dec 17, 2004)

*bump*

My 89 golf is similar...
Everything is fine unless you're starting the car after the engine has recently heated up. Then it wants to rev to 2000 RPM for maybe 15 seconds and creep back down to normal.

I'll have to try cleaning the ISV as I can not see any vacuum leaks 
Any update on your situation?


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## vswager (Dec 15, 2012)

Fat Rabbit said:


> ISV = Idle Stabilizer Valve FR


do not htink this car has a isv brah


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## starksan (Mar 30, 2013)

I'm having the same problem too but, with a 1.8l 8v digi 2. I have erratic idling 850-2250 rpm.


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## vswager (Dec 15, 2012)

starksan said:


> I'm having the same problem too but, with a 1.8l 8v digi 2. I have erratic idling 850-2250 rpm.


digi 2 could be a isv or the temp sensor.


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## sprocket007 (Oct 14, 2002)

Injector 'o' rings can also cause a vacuum leak


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## starksan (Mar 30, 2013)

vswager said:


> digi 2 could be a isv or the temp sensor.


My ISV is purring like a kitten, so I know it isn't that. About to buy a blue CTS, hopefully that'll solve it.



sprocket007 said:


> Injector 'o' rings can also cause a vacuum leak


That's the first I heard of that being the cause.

My idle is rhythmical bouncing from 850-2250 rpm at about 1.5 sec intervals. When I accelerate past 2500 rpm, it runs like a top.


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## starksan (Mar 30, 2013)

I bought a new CTS today. Installed and did the rev over 3k rpm three times with the CTS disconnected to reset it. Attached connector and I'm still experiencing erratic idling. 850-2250 

With the CTS disconnected it idled at 2k rpm continuously. 

The idle screw is bottomed out.

I replaced the knock sensor the week before.

ISV is currently disconnected but, when I reconnected it today after installing to see how it would affect things the idling rpm jump to 3100 and sustained.

Idles at 2k until it gets warm, then it starts acting retarded. Is the O2 sensor next on the list?


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## vswager (Dec 15, 2012)

look, listen and sprey soapy water over vac lines to find leaks


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## starksan (Mar 30, 2013)

vswager said:


> look, listen and sprey soapy water over vac lines to find leaks


I'll give that a try tomorrow and let you know if I find anything. Am I looking for bubbling, or a slight drop in rpm's?


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## vswager (Dec 15, 2012)

starksan said:


> I'll give that a try tomorrow and let you know if I find anything. Am I looking for bubbling, or a slight drop in rpm's?


correct.


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## starksan (Mar 30, 2013)

I checked the vacuum lines and everything is in order. I'm gonna replace all the lines tomorrow just because. I checked the intake tubing for cracks as well and it's in good condition.


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## 92GTIMK2 (Jun 4, 2013)

did you ever sort this out, was it the vaccume lines?


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## starksan (Mar 30, 2013)

Lately, it seems to be slowly correcting its self. Idles at about 850 on cold start and to 1100 when it's warm. But yeah, I replaced every vacuum line and gasket on cylinder head. I'm 90% sure that it's injector related, because I checked and cleaned all the grounds too. So it's either a clogged/leaky injector, or an injector o-ring.


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