Rough idle / hot startup - JeepForum.com

 
LinkBack Thread Tools
post #1 of 11 Old 01-30-2002, 06:02 PM Thread Starter
eraabe
Registered User
 
Join Date: Jan 2002
Location: Ft Lauderdale, FL
Posts: 1
Unhappy Rough idle / hot startup

I have a 4.0. After the engine is warmed up and it's shut off for longer that 10 min, when starting, the engine runs rough like it is missing and might stall. This is worse when you are in gear with the brake applied. After you drive for a few minutes the idle returns to normal. Driving under a load is normal. This will happen again if you allow the engine to sit off for at least 15 min. Got any ideas? The dealer is puzzled. Nothing shows on the computer yet. Thanks Ed aeraabe@aol.com

eraabe is offline  
Sponsored Links
Advertisement
 
post #2 of 11 Old 03-18-2009, 06:49 PM
pajeep
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2006
Location: pa
Posts: 66
engine runs rough for short time when hot, on restart.

My buddy has the same problem. I checked the forum for results. Does anyone have a clue?
pajeep is offline  
post #3 of 11 Old 03-18-2009, 06:59 PM
xjbuilder00
Registered User
1992 XJ Cherokee 
 
Join Date: Feb 2009
Location: Texas
Posts: 112
I have the same problem, replaced all plug wires, rotor, cap, plugs, and injectors. i've cleaned all of the throttle body IAC and everything and it still feels like it's missing alittle. If anyone can figure it out you'd definately be on the awesome list.

Ok, So Whats The Speed Of Dark?

92' Cherokee Laredo - 3.5" OME lift, Rusty's Shocks, JKS quick Discos, Rusty's Adj Trac Bar
xjbuilder00 is offline  
post #4 of 11 Old 03-18-2009, 07:11 PM
Rollin
Registered User
1998 XJ Cherokee 
 
Join Date: Feb 2007
Location: NH
Posts: 1,249
Injector #3 gets so hot in certain conditions that it vaporizes its fuel upon shutdown. I think this is what your problem is. It usually clears within 30 seconds of hot startup. If it happens very often or annoys you, you can wrap insulation around injector 3 and it will block the heat, thus solving the problem.

Edit: found the TSB, It applies to older vehicles too, I just found a different version.

THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 18-027-02,
DATED SEPTEMBER 06, 2002, WHICH SHOULD BE REMOVED FROM
YOUR FILES. THIS IS A COMPLETE REVISION AND NO ASTERISKS
HAVE BEEN USED TO HIGHLIGHT REVISIONS.
SUBJECT:
4.0L Rough Engine Idle After Restart Following A Hot Soak
OVERVIEW:
This bulletin involves the installation of a fuel injector insulator sleeve.
MODELS:
2000-2004 (TJ) Wrangler (Domestic and International Markets)
1999-2004 (WJ) Grand Cherokee (Domestic and International Markets)
2001-2004 (WG) Grand Cherokee (International Market)
2000-2001 (XJ) Jeep Cherokee (Domestic and International Markets)
NOTE: This bulletin applies to vehicles equipped with a 4.0L engine (sales code = ERH)
SYMPTOM/CONDITION:
Customers may describe a 20 to 30 second rough idle following the restart of a heat soaked
engine. This condition may be most noticeable when the engine is restarted following a
prior 10 to 20 minute heat soak in hot ambient conditions of approximately 32 C (90F)
or higher. This condition may be consistent with short city stop-and-go driving trips and
can be aggravated by the use of fuel with a high ethanol content. Depending upon
various conditions a MIL may occur due to DTC P0303 - Cylinder #3 Misfire.
This condition may be caused by heat from the exhaust manifold that following engine
shut down migrates to the area around injector #3 and causes fuel vapor to form
within the injector. This in turn may cause a momentary misfire of cylinder #3 until
the fuel vapor is cleared of injector #3. The insulator sleeve lowers the injector #3
temperature to a point below which the fuel will not normally vaporize.
DIAGNOSIS:
1. If vehicle exhibits a rough idle, and if a misfire of cylinder #3 is observed following
a 10 to 20 minute hot soak, perform the Repair Procedure.
18-031-03 -2-
PARTS REQUIRED:
Qty. Part No. Description
1 56028371AA Ignition Wire Shield
REPAIR PROCEDURE:
1. Cut insulator sleeve, p/n 56028371AA, to make two (2) insulator sleeves
about 25-30 mm (1 in.) in length.
2. Install one sleeve around injector #3, with the slit on the upward facing side of the
injector. Install the other sleeve with the slit on the downward facing side of the injector.
3. Confirm sleeve is flush to intake manifold surface around injector.
4. Check injector #3 wire and ensure that the injector is rotated to a 2 o’clock
position (from driver’s side of vehicle

1998 Jeep Cherokee Classic: Bull Bar, TracLock Chrysler 8.25"
Rollin is offline  
post #5 of 11 Old 03-18-2009, 07:50 PM
pajeep
Registered User
1987 YJ Wrangler 
 
Join Date: Oct 2006
Location: pa
Posts: 66
Thanks. My buddy said he had the computer read and it said #3 cylinder misfire. This must be the problem. I forwarded the info. Thanks. Do you know if this is a recall item with a free repair? Thanks again!!!
pajeep is offline  
post #6 of 11 Old 03-18-2009, 08:18 PM
Rollin
Registered User
1998 XJ Cherokee 
 
Join Date: Feb 2007
Location: NH
Posts: 1,249
I never looked into it

1998 Jeep Cherokee Classic: Bull Bar, TracLock Chrysler 8.25"
Rollin is offline  
post #7 of 11 Old 03-18-2009, 09:08 PM
robsjeepxj
Registered User
2000 XJ Cherokee 
 
Join Date: Sep 2007
Posts: 1,644
Also heat shield between the exhaust and intake manifold works. I did this repair and the results were marginal as the heat sleeves tend to fall off over time and with fans blowing on them so I went with an actual heat shield instead works great, diverts the heat from under the intake and in turn from in to the injectors.
PS it's not just cylinder #3 that this will happen to I've had it happen to varies cylinders as always only on startup.
robsjeepxj is offline  
post #8 of 11 Old 03-19-2009, 07:03 AM
tjwalker
It's the crank sensor!
 
tjwalker's Avatar
1999 XJ Cherokee 
 
Join Date: Nov 2007
Location: Central Minnesota
Posts: 8,765
Garage
eraabe, always post the year of your XJ. It can and does make a difference in the advice you'll receive.

Depending on the year, it could be the heat soak problem. My 99 had this issue but it never did set off the check engine light or store a code.

99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche
Without "data", all you have is an opinion!
tjwalker is offline  
post #9 of 11 Old 03-19-2009, 07:05 AM
Rollin
Registered User
1998 XJ Cherokee 
 
Join Date: Feb 2007
Location: NH
Posts: 1,249
Quote:
Originally Posted by tjwalker View Post
eraabe, always post the year of your XJ. It can and does make a difference in the advice you'll receive.

Depending on the year, it could be the heat soak problem. My 99 had this issue but it never did set off the check engine light or store a code.
Like I said, it applies to at least 97+ Because mine does it too.

1998 Jeep Cherokee Classic: Bull Bar, TracLock Chrysler 8.25"
Rollin is offline  
post #10 of 11 Old 08-25-2009, 02:19 PM
_litz
Registered User
1997 XJ Cherokee 
 
Join Date: Aug 2009
Location: Marietta, GA
Posts: 341
Mine did this too, last weekend ... was towing, stopped for gas, and it misfired on startup (P0301) ... symptoms were exactly as described in that TSB. I cleared the code, and it's not returned.

What kind of heat shield would be recommended to put between the exhaust manifold and the injector rail?

- _litz

1997 Jeep Cherokee Sport
1976 Fairmont MT-19
_litz is offline  
post #11 of 11 Old 06-21-2013, 10:15 PM
XJmike0122
Registered User
2001 XJ Cherokee 
 
Join Date: Jun 2013
Location: Albuquerque
Posts: 259
I know this is a really old post, but I just got a 2001 XJ. Thanks for the info.
XJmike0122 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
Rough Idle/Bogging At Startup danw77 XJ Cherokee Technical Forum 10 07-18-2009 02:55 PM
Runs rough upon startup JeepJinx XJ Cherokee Technical Forum 13 03-10-2009 03:53 PM
Rough accleration only after startup. mdp XJ Cherokee Technical Forum 7 09-05-2004 11:37 PM
Rough startup and hesitation Dstj99 XJ Cherokee Technical Forum 3 05-18-2004 10:25 PM
High idle at startup xjbuck XJ Cherokee Technical Forum 4 08-25-2001 10:22 PM

Posting Rules  
You may post new threads
You may 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 Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome