3.6 Pentastar acceleration hesitation / hiccup - Page 2 - AUSJEEPOFFROAD.COM Jeep News Australia and New Zealand

Go Back   AUSJEEPOFFROAD.COM Jeep News Australia and New Zealand > JEEP GARAGE > JK Wrangler Australia
Register Forums Trading Your Jeep New Garage Mark All Read

Post New Thread  Reply
 
Thread Tools Search this Thread
  #8  
Old 05-01-2018
oscar.kruse  oscar.kruse is offline
I just registered
 
Join Date: Feb 2011
Posts: 17
What Jeep do I drive?: JK
Likes: 0
Liked 0 Times in 0 Posts
Default

I don't have a fuel pressure gauge so for the moment I cant really go down that path. I have checked the brake booster and other vacuum lines and cant see any leaks.

I have still got the stock Y pipe and post cat loop, its just after that where I've removed the other two mufflers and installed smaller ones.
  #9  
Old 06-01-2018
V82xist  V82xist is offline
I just registered
 
Join Date: Jan 2005
Location: Brisbane
Posts: 133
Likes: 145
Liked 53 Times in 22 Posts
Check out my Ride(s)
Default

Quote:
Originally Posted by Classic Boy View Post
In built fuel filters on jeeps are allegedly good for the life of the car, in practise I find them clogged at between 150,000 -200,000kms sometimes sooner for cars operating regularly remote and getting more dirty fuel.
Yep, mine had to be changed at the 48K service due to similar issues.
__________________
No Jeep anymore.
  #10  
Old 06-01-2018
OzRick25  OzRick25 is offline
I just registered
 
Join Date: Jan 2017
Posts: 181
Likes: 39
Liked 49 Times in 45 Posts
Default

Quote:
Originally Posted by oscar.kruse View Post
I don't have a fuel pressure gauge so for the moment I cant really go down that path. I have checked the brake booster and other vacuum lines and cant see any leaks.

I have still got the stock Y pipe and post cat loop, its just after that where I've removed the other two mufflers and installed smaller ones.
Fuel pressure and quality is certainly worth looking into.

You obviously mean physically smaller but less restrictive mufflers if so I wouldn't think them to be the issue. I was quite surprised at the hesitation after fitting a straight through hi flow cat back to my 3.8 with some of the idrive settings that worked fine prior to changing the muffler.

Throttle position sensor would be a good thing to look at if you don't have the tools to look at fuel pressure. I'd take the intake off get someone to bring it up to power in neutral and see what happens to the throtle if it occurs.

If it doesn't occur you've at least removed throttle position and can go back to fuel, spark, manifold absolute pressure/vacuum leak, or restricted exhaust (partly blocked cat)
__________________
07 JKUR manual

Last edited by OzRick25; 06-01-2018 at 06:18 PM.
  #11  
Old 06-01-2018
Classic Boy's Avatar
Classic Boy  Classic Boy is online now
Full Flexer
 
Join Date: Jun 2017
Location: Central Vic
Posts: 797
What Jeep do I drive?: WG
Likes: 23
Liked 283 Times in 208 Posts
Default

Quote:
Originally Posted by V82xist View Post
Yep, mine had to be changed at the 48K service due to similar issues.
I have serviced a lot of cars and a few jeeps over the years and I reckon the fuel filter for life is absolute B/S.
For example a while ago I had a WG petrol jeep with 180,000kms that the owner complained was generally down on towing power particularly on long hill climbs but no other general complaint.
Did a full service and checked the individual cylinders with a plug drop test and it was basically a sound motor. Checked fuel pressure it was lower than spec at idle which is odd because in my experience they are usually spot on spec, so I went to the so called for life fuel filter and replaced it.

The removed filter was absolutely plugged so choked I don't know how the engine even started I suppose that little electric pump is better than I give it credit for, naturally the engine power is fully restored.
Later I cut open the filter housing to see its internal condition and although the housing was around 130-150mm long and about 55mm in diameter the actual filter element only filled half of the housing the other half of the housing was taken up by the pressure regulator, so the filtering element was only around 60mm long and about 50mm in dia, much smaller in size and surface area than most other fuel filters I have cut open from various other makes that their manufacturers reckon should they should be changed around 40,000 or 60,000kms.
The so called filter for life on some jeeps is a joke, not only is the actual element usually smaller they ridiculously suggest it never needs changing

Last edited by Classic Boy; 06-01-2018 at 08:51 PM.
  #12  
Old 07-01-2018
Rod Harrison's Avatar
Rod Harrison  Rod Harrison is offline
Established Member
 
Join Date: Jul 2011
Posts: 148
What Jeep do I drive?: JK
Likes: 0
Liked 16 Times in 7 Posts
Default

Quote:
Originally Posted by OzRick25 View Post
Fuel pressure and quality is certainly worth looking into.

You obviously mean physically smaller but less restrictive mufflers if so I wouldn't think them to be the issue. I was quite surprised at the hesitation after fitting a straight through hi flow cat back to my 3.8 with some of the idrive settings that worked fine prior to changing the muffler.

Throttle position sensor would be a good thing to look at if you don't have the tools to look at fuel pressure. I'd take the intake off get someone to bring it up to power in neutral and see what happens to the throtle if it occurs.

If it doesn't occur you've at least removed throttle position and can go back to fuel, spark, manifold absolute pressure/vacuum leak, or restricted exhaust (partly blocked cat)
Here is where a bluetooth OBDII adapter (quite cheap)and Torque on your mobile could be invaluable. It will allow you to graph your various sensors in real time when it happens again.
__________________
2012 JKU Wrangler
2015 WK Grand Cherokee.
  #13  
Old 08-01-2018
StewartVerity  StewartVerity is offline
I just registered
 
Join Date: Sep 2016
Posts: 11
What Jeep do I drive?: JK
Likes: 0
Liked 4 Times in 3 Posts
Default

I’ve had the same problem now for quite some time-probably from around 65k. It normally happens around 2250-2500 rpm and particularly when accelerating lightly after cruising. It’s intermittent rather than regular and doesn’t happen if accelerating heavily. I’ve replaced the MAP sensor and done a few other bits and pieces to gradually eliminate potential causes. Fuel pressure check and replace the fuel filter is next on the list. I’ll let you know how it goes, or let me know if you get there first.


Sent from my iPhone using Tapatalk
  #14  
Old 08-01-2018
oscar.kruse  oscar.kruse is offline
I just registered
 
Join Date: Feb 2011
Posts: 17
What Jeep do I drive?: JK
Likes: 0
Liked 0 Times in 0 Posts
Default

I removed and cleaned the throttle body about a year ago. Did not fix the issue as i had hoped. I got the Misses to give the engine a few revs while looking down the throttle body. Seemed to move freely without any sticky points.

Was thinking about changing the MAP sensor but hesitate since no fault codes are being thrown.

I ve already got a OBDII adapter. Which sensors exactly do you think i should be graphing ?
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 06:43 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=