High Idle after lift - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Cherokee & Comanche Forums > XJ Cherokee Technical Forum > High Idle after lift

XHD Heavy-Duty Hood Latches for JK and TJ available at OcoRough Country Lift Kits and Parts!Clayton Off Road WJ Long Arm Kits!

Reply
Unread 03-11-2011, 07:51 PM   #1
1998JeepXJ
Registered User
1998 XJ Cherokee 
 
Join Date: Jan 2011
Location: Spokane, WA
Posts: 11
High Idle after lift

Hi, I just installed a 3 in IRO lift kit with 31's. After finishing the install, I started my jeep up and it had a very high idle, I drove it around for awhile hoping that it might go away, but no luck. Any suggestions? Could it be since I raised and lowered it so many times on a 2 post that the ECM is freaking out? maybe I messed something up in the install, I'm unsure, but any ideas would be helpful. thanks.

1998JeepXJ is offline   Reply With Quote
Unread 03-11-2011, 07:55 PM   #2
CJ7-Tim
Real Jeeps have dents.
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis, Minnesota
Posts: 21,614
High idle is either a manifold vacuum leak, a Throttle Position Sensor problem, or a Idle Air Controller problem. Inspect the vacuum hose and intake manifold for any loose hoses or leaks, test the TPS. Clean the idle air controller and housing.
__________________
.

According to the National Shooting Sports Foundation, AR-15 sporting rifles account for nearly 20% of all U.S. firearms sales.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ......

Originally Posted by Ronald W. Reagan: Government is not the solution to our problems; Government is the problem.
CJ7-Tim is offline   Reply With Quote
Unread 03-12-2011, 02:10 AM   #3
1998JeepXJ
Registered User
1998 XJ Cherokee 
 
Join Date: Jan 2011
Location: Spokane, WA
Posts: 11
Thanks, Ill check the hoses and go ahead and clean that tommorow if a leaks not the issue. Hopefully ill be able to fix it. I think it might have something to do with the throttle, it will accelerate to 30 mph over about 30 seconds without hitting the gas peddle.
1998JeepXJ is offline   Reply With Quote
Unread 03-12-2011, 02:26 AM   #4
CJ7-Tim
Real Jeeps have dents.
 
CJ7-Tim's Avatar
2000 XJ Cherokee 
 
Join Date: Apr 2002
Location: out in the garage - Minneapolis, Minnesota
Posts: 21,614
Quote:
Originally Posted by 1998JeepXJ View Post
.... it might have something to do with the throttle, it will accelerate to 30 mph over about 30 seconds without hitting the gas peddle.
That is a very important symptom and it changes what to look for.

Then you need to test the Throttle Position Sensor ASAP.

TPS TEST

You should have 5 volts going into the Throttle Position Sensor (TPS). It is best to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. At idle, TPS output voltage should be greater than .26 volts but less than .95 volts. Move the throttle and look for smooth meter response up to the 4.49 at WOT. The other wire will be the ground and should show no voltage.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.


The TPS is sensitive to heat, moisture, and vibration, leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following:

-Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".

- High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.

-Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.
__________________
.

According to the National Shooting Sports Foundation, AR-15 sporting rifles account for nearly 20% of all U.S. firearms sales.

Progressive Liberalism: Bringing you new Healthcare ideas so wonderful, they have to include mandatory participation ......

Originally Posted by Ronald W. Reagan: Government is not the solution to our problems; Government is the problem.
CJ7-Tim is offline   Reply With Quote
Unread 03-12-2011, 07:32 AM   #5
cbordea
Registered User
1998 XJ Cherokee 
 
Join Date: Nov 2008
Location: NC
Posts: 734
we were doing some work on my sons jeep and knocked a small vaccum line off the manifold as mentioned earlier. It idled high and the other key was the cruise wouldn't work. We plugged it back in and voila!
__________________
88 MJ I6 4x4 Stock my hauler - Sold
98 XJ I6 4X4 Stock my son's DD
06 12V Purple Barbie Jeep my daughter's DD :-)
cbordea is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.