High idle need a fix.

Dessertrunner · #1 09-25-2006, 05:14 AM

Okay, I need help with high idle on my car I have changed the air by pass value under the throttle body and I still have problems do any of you guys have any suggestions. Some times when I restart the car it will be perfect then next time when I start it it idles to high and won't fix till I stop the engine and restart. I thought it might be the temp sensor but mesured the restance and it all suits the numbers in the work shop manuel. Replaced the trottle position sensor and still no better. All ideas and suggestions greatly appricated.
Tony

msvx95 · #2 09-25-2006, 05:17 AM

How tight is your throttle cable?? If it's got no slack at all the throttle body may be open causing high idle at startup.

Dessertrunner · #3 09-26-2006, 06:46 AM

Good thought I will check it but generally I have been carefull with them. Its funny as one time you start the engine and it idles perfect next its to high.
Tony

gtdanielgt · #4 09-26-2006, 08:59 AM

Possible causes (from my experience with the SVX and other cars)

1. Sticky throttle cable
2. Loosing vacuum somewhere
3. Idle air control valve
4. Throttle position sensor

That's all I can think of for now Tony.. But it's a good place to start.. Let us know your findings.

-Daniel

Earthworm · #5 09-26-2006, 11:51 AM

What about a dirty throttlebody?

Dessertrunner · #6 09-27-2006, 04:58 AM

When it is playing up if you rev the engine it doesn't come back to the correct rev for a long time. I wonder about the throttle body never though of that I will give it a go. What about some of the small solinodes under the intake manifold if any of those were stuck on would it cause the loss vacuum.
Tony

northernkanuck · #7 11-18-2006, 11:34 AM

Hi Tony, did you ever find a fix for this problem as I am experiencing the same thing and have not been able to find out the cause.

Keith

Dessertrunner · #8 11-18-2006, 02:31 PM

Keith I haven't found it yet and still working on it. In your case I would suggest that you check the intake snorkel with a mirror the most common thing that stuffs the idle is that when the snorkel is put back on it flods on the under side and you can't see it. Use a mirror and let me know how you go. I am working on a way to isulate the problem but as yet haven't got there.
Tony

northernkanuck · #9 11-19-2006, 07:43 PM

Thanks Tony, I already checked the snorkel and it is fine. One thing I did notice today was the A/C seems to be staying on and it is 0' celcius. I took out the 10 amp fuse for the A/C under the hood and the idle dropped down to where it should be. Unfortunately it is dark and cold now so I will have to look into this later. In the meantime I can monitor things and see if there is an improvement.

Keith

northernkanuck · #10 11-19-2006, 07:46 PM

oh by the way I have already tried all the above mentioned suggestions as well as a lot of other solutions which I have come across on the site with no success, fortunately I have a parts car and am able to swap out parts. So far nothing has helped.

Keith

Dessertrunner · #11 11-20-2006, 12:52 AM

Keith On a SVX the AC is always on it goes off when you push the button on the dash marked AC and the light comes on. There is nothing wrong with your AC it is just standard. If the idle dropped off when you turn the Eviro system off then the problem will be the Auxiliary Air Control Value. This is the one under the manafold not the one attached to the throttle body. If you can get some throttle body spray cleaner in there you might get it to stop sticking and then the idle will sort its self out.
In winter I have then Eviro system on auto then push the button on ACC and the system says its in Manuel but it still operates just has the AC unit off. This also saves a bit of fuel.
Tony

Earthworm · #12 11-20-2006, 10:29 AM

A/C also runs when the defrost is on. I've noticed it will run as long as the temperature is above -5°C or so. Below that it doesn't run.

northernkanuck · #13 11-21-2006, 05:32 PM

Hi Tony, first I put the a/c fuse back in. I checked the Aux idle valve according to Billb's writeup - when it is cold I can blow through no problem. When it is warmed up I can blow through a little bit. I waited for it to cool down and sprayed TB cleaner and ran the car last night, no difference. This morning I decided to spray some more cleaner in since the write up recommends doing it when the car is cold, well as I went to pull the hose off the top of the throttle body it snapped in half - I guess it was old and brittle and the fact it was -3' C didn't help. So here it was 7 am and I am standing there with part of a hose the car requires in order to start. I found a plastic plug that fit loosely in the end of the hose and siliconed around it and attached it back to top of the throttle body. Car started fine and idled at 1500 rpm until warm then settled in around 610 rpm. Car drove like a charm to work. After work car started fine, idle at 1500 rpm but once it warmed up it would not go below 850 rpm for the drive home.
I thought the valve allowed extra air into the manifold for warmup which caused the higher idle, yet I still had a higher cold idle with the hose blocked off? The idle responded exactly as it should with the valve properly attached when cold yet it was not attached. I really wish I could figure this out.
Thanks for your help.

Keith