WH CRD Slow idle causing belt vibration - AUSJEEPOFFROAD.COM Jeep News Australia and New Zealand

Go Back   AUSJEEPOFFROAD.COM Jeep News Australia and New Zealand > JEEP GARAGE > XH Commander and WH Grand Cherokee
Register Forums Trading Your Jeep New Garage Mark All Read

Post New Thread  Reply
 
Thread Tools Search this Thread
  #1  
Old 29-05-2014
Redbaron57's Avatar
Redbaron57  Redbaron57 is offline
AJOR Gold
 
Join Date: Aug 2008
Location: Country SA
Age: 66
Posts: 79
What Jeep do I drive?: WH
Likes: 5
Liked 12 Times in 11 Posts
Default WH CRD Slow idle causing belt vibration

My serpentine belt vibrates making a rattling noise at idle with the engine cold. The belt, idlers, water pump, tensioner and glow plugs are all new.

The idle speed is about 640 rpm. The vibration goes away when the engine speed is increased to about 670 rpm. I read on a forum somewhere that the idle speed has closed loop control and is supposed to be 760 rpm. (I have not found any reference to this in the Service Manual.)

Does anyone have clues to help restore a smooth idle to my 130,000 km engine?
  #2  
Old 29-05-2014
Clarky's Avatar
Clarky  Clarky is offline
Irok Bandit
 
Join Date: Apr 2012
Location: Wang NSW
Age: 56
Posts: 4,431
What Jeep do I drive?: JT
Likes: 479
Liked 1,189 Times in 788 Posts
Check out my Ride(s)
Default

Could be your Alternator pulley
www.youtube.com/watch?v=OR0WEK3JEO4http://www.ebay.com.au/itm/111136891...84.m1423.l2649
__________________
SOLD 06 Limited G/C QuadraDrive II Lovells 2"Lift +30 rims 265/70/17 Imported Saguaro Bar Stedi

Last edited by Clarky; 29-05-2014 at 09:13 PM.
  #3  
Old 30-05-2014
Hanna's Avatar
Hanna  Hanna is offline
Lowranger Shocker
 
Join Date: Jun 2009
Location: Karratha, WA (Ex Geelong)
Age: 45
Posts: 1,636
What Jeep do I drive?: XH
Likes: 641
Liked 184 Times in 136 Posts
Default

Yep - Clarky's onto it!

Had the same thing on my wife's KJ CRD and it was the alternator de-coupler pulley. Remove the alternator, soak the thread in WD40 and then use a rattle gun with an internal hex bit to remove. You may need to jam a large screwdriver in to stop the centre from rotating, but it will come. I changed it over and it has been fine ever since.

The violent nature of the diesel power stroke means that the clutch in the pulley wears out over time. To have no clutch pulley though, well you can see the results in Clarky's video.

Good luck!
__________________
  #4  
Old 30-05-2014
fester's Avatar
fester  fester is offline
No Winching
 
Join Date: Jun 2010
Posts: 3,145
What Jeep do I drive?: WJ
Likes: 83
Liked 301 Times in 244 Posts
Default

Another tell tale is a little chirp just as the alternator comes to a stop when you turn the car off.
You can get the proper tool for removing the pulley quite cheaply on eBay if you don't have access to a rattle gun. The drive for the bolt is actually a fine spline not a socket head (hex drive).
If this is the problem don't try buying locally it will cost you hundreds compared to about $80 o/s. I replaced mine in the 2.7, good time to do the internal bearings in the alternator as well. They are common and cheap.
__________________
I got a sweater for Chrissy, nothing wrong with that except I was hoping for a moaner or a screamer.
  #5  
Old 30-05-2014
Redbaron57's Avatar
Redbaron57  Redbaron57 is offline
AJOR Gold
 
Join Date: Aug 2008
Location: Country SA
Age: 66
Posts: 79
What Jeep do I drive?: WH
Likes: 5
Liked 12 Times in 11 Posts
Default

Thanks gents. You are right. I will get onto it. I observed that the inertia of the alternator causes the tension side of the belt to go slack when the crank slows down against compression. I thought it was just a low speed harmonic thing. I didn't know there was a sprag clutch in the pulley, which seemed solid when I changed the belt. It must be seized. Never too old to learn! I hope the sudden accelerations haven't started my armature disintegrating. It probably explains the failure of a friend's alternator at 120,000-odd km. Cheers.

Last edited by Redbaron57; 30-05-2014 at 04:44 PM. Reason: Grammatical error
  #6  
Old 16-06-2014
Redbaron57's Avatar
Redbaron57  Redbaron57 is offline
AJOR Gold
 
Join Date: Aug 2008
Location: Country SA
Age: 66
Posts: 79
What Jeep do I drive?: WH
Likes: 5
Liked 12 Times in 11 Posts
Default

Last word on this issue: New pulley from US via eBay $80. Set of universal tools for pulley removal $53 via eBay. The WH needed a 30 point spline tool to fit the pulley with a T50 Torx adapter through the middle to turn the alternator shaft. I did the job insitu after removing the engine cover and plastic shield underneath. After cracking the pulley thread, which is not easy as it was very tight, I used a 17mm socket on a strong bar held by a ratchet strap on the shed wall to hold the belt tensioner while I changed the pulley with the belt in place. It took about an hour including some stuffing about. The old pulley was seized solid. With the new pulley the belt rattle at low engine speed is gone and the tensioner no longer pulses violently. I will still remove the alternator to replace brushes and bearings as a precaution since a friends brushes wore-out and destroyed the slip rings. Thanks Clarky, Hanna and fester for your advice.
Likes: (2)

Last edited by Redbaron57; 16-06-2014 at 05:10 PM.
  #7  
Old 16-06-2014
fester's Avatar
fester  fester is offline
No Winching
 
Join Date: Jun 2010
Posts: 3,145
What Jeep do I drive?: WJ
Likes: 83
Liked 301 Times in 244 Posts
Default


Cool bananas
__________________
I got a sweater for Chrissy, nothing wrong with that except I was hoping for a moaner or a screamer.
Post New Thread  Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On





All times are GMT +10. The time now is 03:14 PM.


Advertisements




AJOR does not vouch for or warrant the accuracy, completeness or usefulness of any message, and are not responsible for the contents of any message. The messages express the views of the author of the message, not necessarily the views of AJOR or any entity associated with AJOR, nor should any advice be substituted as technical advice replacing that of a mechanic. You agree, through your use of this service, that you will not use AJOR to post any material which is knowingly false and/or defamatory, inaccurate, abusive, vulgar, hateful, harassing, obscene, profane, sexually oriented, threatening, invasive of a person's privacy, religious, political or otherwise violative of any law. You agree not to post any copyrighted material unless the copyright is owned by you or by AJOR. The owner, administrators and moderators of AJOR reserve the right to delete any message or members for any or no reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold harmless AJOR, the administrators, moderators, and their agents with respect to any claim based upon transmission of your message(s). The use of profile signatures to intentionally mislead or misdirect any member on this forum is not acceptable and may result in your account being suspended. Any trip that is organised through the AJOR forum is participated at your own risk. If you or your vehicle is damaged it is your responsibility, not that of the person that posted the thread, message or topic initiating the trip, nor the organisers of AJOR or moderators of any specific forum. This forum and associated website is the property of AJOR. No user data is harvested and no information supplied in your registration will be sold for profit.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

AJOR © 2002 - 2024 AUSJEEPOFFROAD.COM. All corporate trademarked names and logos are property of their respective owners. Ausjeepoffroad is in no way associated with DaimlerChrysler Corporation or Fiat Jeep.
www.ausjeep.com www.ausjeep.com.au www.midlifemate.com ausjeepforum.com www.r9kustoms.com
vB Ad Management by =RedTyger=