Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here XJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.

HELP, high idle issue!

Thread Tools
 
Search this Thread
 
Old 10-10-2012, 10:27 AM
  #16  
Junior Member
 
Tfox671's Avatar
 
Join Date: Sep 2012
Location: Illinois
Posts: 72
Likes: 0
Received 0 Likes on 0 Posts
Year: 1987
Model: Cherokee
Engine: 4.0 HO
Default

My map sensor was all dirty cleaned it and the plug and jeep ran just fine.
Old 10-10-2012, 03:51 PM
  #17  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes on 1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Renix CPS Testing and Adjusting
 
 
Renix CPSs have to put out a strong enough signal to the ECU so that it will provide spark.
Most tests for the CPS suggest checking it for an ohms value. This is unreliable and can cause some wasted time and aggravation in your diagnosis of a no-start issue as the CPS will test good when in fact it is bad.
The problem with the ohms test is you can have the correct amount of resistance through the CPS but it isn’t generating enough voltage to trigger the ECU to provide spark.
Unplug the harness connector from the CPS. Using your voltmeter set on AC volts and probing both wires in the connector going to the CPS, crank the engine over. It won’t start with the CPS disconnected.
You should get a reading of .5 AC volts.
If you are down in the .35 AC volts range or lower on your meter reading, you can have intermittent crank/no-start conditions from your Renix Jeep. Some NEW CPSs (from the big box parts stores) have registered only .2 AC volts while reading the proper resistance!! That’s a definite no-start condition. Best to buy your CPS from Napa or the dealer.
Sometimes on a manual transmission equipped Renix Jeep there is an accumulation of debris on the tip of the CPS. It’s worn off clutch material and since the CPS is a magnet, the metal sticks to the tip of the CPS causing a reduced voltage signal. You MAY get by with cleaning the tip of the CPS off.
A little trick for increasing the output of your CPS is to drill out the upper mounting hole, or slot it so the CPS bracket rests on the bell housing when pushed down. Then, when mounting it, hold the CPS down as close to the flywheel as you can while tightening the bolts.

 
 
Revised 07-30-2012
Old 10-14-2012, 09:43 PM
  #18  
Senior Member
 
cherokeelaredo'90's Avatar
 
Join Date: Aug 2011
Location: California
Posts: 604
Likes: 0
Received 1 Like on 1 Post
Year: 1990
Model: Cherokee
Engine: 4.0 i6
Default

Hey Cruiser, when you add those two other grounds what bolts do you go from and too?
Old 10-14-2012, 10:05 PM
  #19  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes on 1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by cherokeelaredo'90
Hey Cruiser, when you add those two other grounds what bolts do you go from and too?
Which grounds are you referring to?
Old 10-14-2012, 10:22 PM
  #20  
Senior Member
 
cherokeelaredo'90's Avatar
 
Join Date: Aug 2011
Location: California
Posts: 604
Likes: 0
Received 1 Like on 1 Post
Year: 1990
Model: Cherokee
Engine: 4.0 i6
Default

In your ground refresh how to you talk about adding two other grounds one from the firewall to a bolt on the manifold and a second from the battery negative cable to the radiator support. For the firewall to the manifold which bolts do you use? The one that the braided cable is attached to?
Old 10-14-2012, 10:37 PM
  #21  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes on 1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

Originally Posted by cherokeelaredo'90
In your ground refresh how to you talk about adding two other grounds one from the firewall to a bolt on the manifold and a second from the battery negative cable to the radiator support. For the firewall to the manifold which bolts do you use? The one that the braided cable is attached to?
I use one of the fuel rail bolts there at the manifold.

At the radiator support I use one of the bolts near the battery that bolt DOWN into the radiator support.
Old 10-14-2012, 10:42 PM
  #22  
Senior Member
 
cherokeelaredo'90's Avatar
 
Join Date: Aug 2011
Location: California
Posts: 604
Likes: 0
Received 1 Like on 1 Post
Year: 1990
Model: Cherokee
Engine: 4.0 i6
Default

Originally Posted by cruiser54

I use one of the fuel rail bolts there at the manifold.

At the radiator support I use one of the bolts near the battery that bolt DOWN into the radiator support.
Oh alright thanks!
Old 10-15-2012, 06:49 AM
  #23  
::CF Moderator::
 
cruiser54's Avatar
 
Join Date: Aug 2011
Location: Prescott, Az
Posts: 43,971
Received 1,559 Likes on 1,263 Posts
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
Default

I meant heat shield bolts. Ooops.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
southfloridajeeps
Modified XJ Cherokee Tech
32
03-04-2023 01:10 PM
xjwolfman
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
8
08-26-2020 12:59 PM
Expedition_XJ
Cherokee Chat
25
05-24-2018 11:40 AM
shelby5041
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
39
11-07-2015 01:22 AM
australian_expat
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
4
09-02-2015 09:02 PM

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


Quick Reply: HELP, high idle issue!



All times are GMT -5. The time now is 07:21 AM.