Idle Speed

Tiny
IBEAREDNECKWOMAN
  • MEMBER
  • 1989 JEEP CHEROKEE
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 172 MILES
I have an 89 Jeep Cherokee that is idling at a high speed.I was having trouble when I would first start it. It would run for a minute or two then try to shut off. So, I cleaned the throttle body, TPS, and the idle air control sensor. Now it is idling at a dangerously high speed and it is over-riding the brakes. Any suggestions on what would fix this problem? Also, where can I find the idle control adjustment screw on my vehicle? Please help! Thank you!
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Sunday, January 23rd, 2011 AT 3:52 AM

7 Replies

Tiny
CJ MEDEVAC
  • EXPERT
MAYBE YOUR IAC (IDLE AIR CONTROL IS STUCK (INTERNALLY), OR DAMAGED MAYBE FROM THE CLEANING)

OR MAYBE YOUR THROTTLE CABLE/ LINKAGE IS HUNG UP ON THE THROTTLE BODY.

SEE SOMETHING IS PINCHED OR IN A BIND.

OTHER THAN THAT, I MIGHT SAY ITS YOUR THROTTLE POSITION SENSOR.

IS YOUR CHECK ENGINE LIGHT ON?

YOUR TURN

THE MEDIC
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Sunday, January 23rd, 2011 AT 3:54 PM
Tiny
IBEAREDNECKWOMAN
  • MEMBER
Thank you for your response. The check engine light is not on. I will check out the other things your mentioned and get back to you. Thanks again!
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Sunday, January 23rd, 2011 AT 9:34 PM
Tiny
IBEAREDNECKWOMAN
  • MEMBER
I also checked the throttle cable and linkage and all appears to be moving freely and isnt binding or hung up anywhere that I can see. I am perplexed that its not throwing any codes, it's hard to narrow down. It did not idle highly before I cleaned the throttle body, IAC, or TPS, only would try 2 stall after starting and running for a few mins, then be fine once warmed up. Hoping I didn't create additional probs by cleaning these things and putting back together, since the high idle developed after cleaning everything. Vaccum lines all seem to be connected. I also tried disconnecting the neg. Batt term then reconnecting thinking it may reset the computer with no luck. Should I just replace the IAC or TPS or is there any thing else to try? Also, is there any such thing as an idle adjustment screw that I can adjust or turn down? Thanks for the help with this!
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Monday, January 24th, 2011 AT 1:21 AM
Tiny
CJ MEDEVAC
  • EXPERT
How and What did you clean these items with?

The Medic
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Monday, January 24th, 2011 AT 2:49 AM
Tiny
IBEAREDNECKWOMAN
  • MEMBER
I used IAC (aerosal) cleaner from Advance auto and Throttle body cleaner (aerosal)for the throttle body and TPS. They said they were sensor safe for IAC and TPS. I just unplugged the wiring and unscrewed the hex screws holding in the IAC and TPS in the throttle body and I unscrewed and removed the big air breather tube on top of the throttle body and sprayed and wiped clean the butterfly valve and all around till it was all shiny and wiped dry and put everything back together after letting dry out about 4 hrs. Then started up fine, ran a little rich, then the idle increased after 2-3 mins and has been stuck quite high. Maybe it needs time to relearn the idle speed since it is so clean in there now, or the IAC is stuck or TPS is bad. Hopefully thats it not the computer. I'm thinking IAC or TPS since it was running fine only almost stalling after starting, then after cleaning the high idle issue began. I have to try to get it in the shop tomorrow unless I should replace a sensor myself. Its even high when driving, it will almost override the brakes when stopped at a stop sign and try pulling out on its own. If u release the brakes it will idle itself up to about 30mph with no gas pedal. Kinda dangerous it takes alot more braking to over power the extra rpms. When sitting in the driveway idling it just screams. It starts ok then after a min climbs up in rpm's and remains high. Put it in drive and it lowers some, but still high compared to normal. It's driving us crazy, it's our only vehicle at the moment and with the winter weather it's gotta be on the road. I wish it could sit and fixed at my own pace. That's why it just might go to the garage and save me frustration unless it's something simple to do myself. I apprechiate your time and assistance. -Dave
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Monday, January 24th, 2011 AT 4:55 AM
Tiny
CJ MEDEVAC
  • EXPERT
Was there anything on the "Breather Tube" you might have failed ti hook back up?

Is your IAC fully seated and no vacuum leak. You can check with any flammable aerosol, carb cleaner, starter fluid (even hairspray) Squirt around it (without getting it in the throttle body) listen for engine speed to change. Have a blanket or fire extinguisher nearby. You never know, 'specially with your winning streak now!

This may sound dumb but, Maybe disconnect the battery for 5 minutes then reconnect. Works on some stuff, won't hurt to try.

If you go to Autozone or Advance Auto Online, maybe replacing the IAC and TPS would be cheaper than a Shop. If that's your problem.

I always look at parts changing for a cure, as : Their old and worn anyway, this is just a insurance policy for the future, even if it's not the problem

It does really seem suspicious that, that's what you messed with and now you have a different factor in the equation.

About I can dig up. Still let me know what happens, This is how I learn too!

The Medic
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Monday, January 24th, 2011 AT 5:28 AM
Tiny
IBEAREDNECKWOMAN
  • MEMBER
Turns out with the help of a mechanic buddy, that the throttle cable needed an adjustment it was hung up somewhere I couldnt see or feel, and he adjusted the TPS and now everything seems to be good to go, just like it should be. He also checked for vaccum leaks all was good. 2 simple adjustments, a throttle cable and whatever adjustment he made to the TPS seemed to solve the issue. No new parts needed. I managed to not spend anything this time, but keeping fingers crossed. Thanks again for all your help, maybe talk with you in the future. Thanks again, Dave
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Tuesday, January 25th, 2011 AT 4:46 PM

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