Idle speed goes up as temp goes up. Why?

[turborebel]

When the idle is set right for start up it then goes to 2000 after it warms up. When I reset it for normal operating temp and then start it the next day it doesn't want to idle unless I hold down the thottle a little. What should I check or replace first?


Thanks, Brent W.

 

[turborebel]

Well, I replaced the throddle body with a rebuilt unit with new sensors. The problem is still there. I checked the O2 sensor and it seems OK. What else can I check?

 

[phunny]

Do you have any boost leaks?

 

[EclipseRacing99]

check the throttle cable. if it is to tight it wont let you car come back down to a normal idle.

 

[turborebel]

I'll check both of those tonight. I also ordered a new O2 sensor just to be shure its OK. Thanks for the help.

 

[turborebel]

OK, I did have a small boost leak and my throddle cable was too tight. I fixed both problems but the high idle did not change. It must be the O2 sensor.

 

[turboglenn]

I have a friend battling the same issue, his car will sometimes hit 2500RPM at a light. We've done a new/used TB, rebuilt his TB, changed and adjusted TPS, 2 different ISC's and we got nothing!!!!!!

Still does it. I told him to check every vacuum line on it for leaks, he said he did, but i can tell he didn't since all teh same dust and dirt is on all the vacuum lines it's easy to tell they haven't been touched adn i'm not doing everything for him for free (all my friends just expect me to be happy to fix their shit for free...it gets old fast! )

 

[siceclipse]

I had the same problem for 2 years till i found it.

the throttle cable was too tight on the Cruise Control box.

I backed the nut of 2 full turns and BAM!

775RPM

 

[Artago]

I have a friend battling the same issue, his car will sometimes hit 2500RPM at a light. We've done a new/used TB, rebuilt his TB, changed and adjusted TPS, 2 different ISC's and we got nothing!!!!!!

Still does it. I told him to check every vacuum line on it for leaks, he said he did, but i can tell he didn't since all teh same dust and dirt is on all the vacuum lines it's easy to tell they haven't been touched adn i'm not doing everything for him for free (all my friends just expect me to be happy to fix their shit for free...it gets old fast! )

Uh... so do you have a suggestion then? Besides check the Vac lines. Could you cap them off maybe and see if it goes away?

Tom

 

[turboglenn]

I had the same problem for 2 years till i found it.

the throttle cable was too tight on the Cruise Control box.

I backed the nut of 2 full turns and BAM!

775RPM

Which of the 3 cables was it? From pedal to cruise box, or from cruise box to TB? I wouldn't think you'd have to worry about the one going from the cruise box to the cruise diaphram/actuater thing on the passenger shock tower.

 

[siceclipse]

I turned out both since they were in so tight.

the one for the diaphram and the one from the box to the TB.

 

[Artago]

I had the same problem for 2 years till i found it.

the throttle cable was too tight on the Cruise Control box.

I backed the nut of 2 full turns and BAM!

775RPM

Sweet thanks. I'll give it a shot.

 

[turboglenn]

Uh... so do you have a suggestion then? Besides check the Vac lines. Could you cap them off maybe and see if it goes away?

Tom

Sorry i was more or less saying that you aren't the only one and we still haven't figured out my friends car so when/if we do i'll let you know what fixed it.

But yea, try capping off all the vacuum lines one at a time and see if you can find one that makes the idle go down. There's got to be something pretty simple going on since so many people seem to get this same problem. That's what i've been trying to get my friend to do.

 

[turborebel]

I loosened the throddle cable some more and that helped alot. Thanks

 

[Artago]

I loosened the throddle cable some more and that helped alot. Thanks

I did the same thing as well as tightening the BISS screw and lowered my HOT idle from 2200 to about 1800 but it's still no where near what it's supposed to be. Any ideas or suggestions? What would cause the car to idle high when hot? Cold idle is 800-900 RPM.

Any and all input is appreciated.

Thanks,

Tom

 

[romeen]

Normal idle when cold, a steady high idle when warm is typical of the throttle cable being too tight. I know you loosened yours but you may have to loosen it some more.

Here is a good post on properly adjusting the cable.

http://www.dsmtuners.com/forums/tuning-engine-management/241449-tps-reading-idle.html#post151021480

 

[turboglenn]

We loosened the cables at the cruise bx and TB on my friends and his is back to normal again too Big thanks to the person who mentioned this.