misfire cylinder 3
12-17-2009 | 05:13 AM
#16
Thread Starter
Junior Member
Joined: Nov 2009
Posts: 54
Likes: 0
From: nj
Year: 2000
Model: Cherokee
Engine: I6 4.0L
I really cannot understand how the fuel can boil/vaporize in the injector.
All the injectors are tied to a common fuel rail. The fuel is being pump through the fuel rail under pressure. It sounds more like a bad injector or a leaking (o-rings) injector that is making that particular cylinder run very lean, this will also create a lot of heat in that cylinder. Once you start having injector problems, it's probably better to replace all the injectors. If you chose to replace the injectors, look on Ebay for a set of reconditioned Mustang GT 5.0 injectors. They have 4 holes in the end of the injector that better vaporizes the fuel and actually increases HP. These are ultrasonically cleaned and matched for volume output. They will also come with new o-rings. A complete set for $115 to $125.
I had an injector that was leaking down and a new replacement was $75 to $100. Good Luck!
All the injectors are tied to a common fuel rail. The fuel is being pump through the fuel rail under pressure. It sounds more like a bad injector or a leaking (o-rings) injector that is making that particular cylinder run very lean, this will also create a lot of heat in that cylinder. Once you start having injector problems, it's probably better to replace all the injectors. If you chose to replace the injectors, look on Ebay for a set of reconditioned Mustang GT 5.0 injectors. They have 4 holes in the end of the injector that better vaporizes the fuel and actually increases HP. These are ultrasonically cleaned and matched for volume output. They will also come with new o-rings. A complete set for $115 to $125.
I had an injector that was leaking down and a new replacement was $75 to $100. Good Luck!
12-17-2009 | 06:23 AM
#17
Member
Joined: Jul 2009
Posts: 168
Likes: 0
From: Goldsboro, NC
Year: 2001
Model: Cherokee
Engine: 4.0
I have the same problem and so far the 2 success stories I heard were wrapping the exhaust and the other one was installing a separate electric fan switch to blow out the hot air when you cut the engine off... I put in a switch a couple of days ago and I also have hood vents so I'll know in a couple of weeks if this helps my problem... I will say that when I cut the engine off and turn the fan on, the amount of heat that gets blown through the hood vents and even under the vehicle is tremendous... I only use it when I think the heat soak may affect the restart. I just run the fan for a minute with the engine off to blow the hot air out and so far (a couple of days) it's been good...
12-17-2009 | 09:42 AM
#18
Newbie
Joined: Oct 2009
Posts: 15
Likes: 0
Year: 1995
Model: Cherokee
Engine: 4.0L HO
I don't think I said anything about larger injectors. I stated that the stock injectors have a single hole and the 5.0 injectors have 4 holes in the nozzle end. Both injectors are 20 pound injectors. The Mustang Injectors atomize the fuel better and therefore are more efficient, ie, more power.
The injectors in most Cherokee's are cheap and most of them have 100,000 to 250,000 miles on them. A better more efficient injector does not mean a bigger injector. I feel you are trying to remedy the effect and not the cause. This condition did not exist for most of the life of this Jeep, it has probably only occured later in the Jeeps life and therefore there is a cause that needs to be remedied.
The injectors in most Cherokee's are cheap and most of them have 100,000 to 250,000 miles on them. A better more efficient injector does not mean a bigger injector. I feel you are trying to remedy the effect and not the cause. This condition did not exist for most of the life of this Jeep, it has probably only occured later in the Jeeps life and therefore there is a cause that needs to be remedied.
12-17-2009 | 10:13 AM
#19
CF Veteran
Joined: Oct 2007
Posts: 3,883
Likes: 6
From: W-PA
Year: 2001
Model: Cherokee
Engine: 4.0
I really cannot understand how the fuel can boil/vaporize in the injector.
All the injectors are tied to a common fuel rail. The fuel is being pump through the fuel rail under pressure. It sounds more like a bad injector or a leaking (o-rings) injector that is making that particular cylinder run very lean, this will also create a lot of heat in that cylinder. Once you start having injector problems, it's probably better to replace all the injectors. If you chose to replace the injectors, look on Ebay for a set of reconditioned Mustang GT 5.0 injectors. They have 4 holes in the end of the injector that better vaporizes the fuel and actually increases HP. These are ultrasonically cleaned and matched for volume output. They will also come with new o-rings. A complete set for $115 to $125.
I had an injector that was leaking down and a new replacement was $75 to $100. Good Luck!
All the injectors are tied to a common fuel rail. The fuel is being pump through the fuel rail under pressure. It sounds more like a bad injector or a leaking (o-rings) injector that is making that particular cylinder run very lean, this will also create a lot of heat in that cylinder. Once you start having injector problems, it's probably better to replace all the injectors. If you chose to replace the injectors, look on Ebay for a set of reconditioned Mustang GT 5.0 injectors. They have 4 holes in the end of the injector that better vaporizes the fuel and actually increases HP. These are ultrasonically cleaned and matched for volume output. They will also come with new o-rings. A complete set for $115 to $125.
I had an injector that was leaking down and a new replacement was $75 to $100. Good Luck!
Now for my recently wrapped fuel rail, it FAILED. It misfired the other day after an hour drive. I stopped at Jared's to spend a couple hundred on diamonds and when I was done it misfired like mad. No CEL though. I waited till it settled down and then drove to jiffy lube for an application. It misfired like mad again. I then had to pee so I drive to the nearest Giant Eagle and propped open the hood before I went in. It didn't misfire, in fact it started up PERFECTLY like a brand new engine. It's heat related for sure.
next step: modify the fan timer
12-17-2009 | 09:52 PM
#20
Thread Starter
Junior Member
Joined: Nov 2009
Posts: 54
Likes: 0
From: nj
Year: 2000
Model: Cherokee
Engine: I6 4.0L
I have the same problem and so far the 2 success stories I heard were wrapping the exhaust and the other one was installing a separate electric fan switch to blow out the hot air when you cut the engine off... I put in a switch a couple of days ago and I also have hood vents so I'll know in a couple of weeks if this helps my problem... I will say that when I cut the engine off and turn the fan on, the amount of heat that gets blown through the hood vents and even under the vehicle is tremendous... I only use it when I think the heat soak may affect the restart. I just run the fan for a minute with the engine off to blow the hot air out and so far (a couple of days) it's been good...
12-18-2009 | 01:58 AM
#21
Newbie
Joined: Nov 2009
Posts: 3
Likes: 0
Model: Cherokee
I know you may not want to hear this but Im currently having the same problem with my 2000 XJ, on taking it to my mechanic they did all these diagnostics mentioned here and also changing coil bar and a few others. Mine was missing on cyl 5 and occasionally 6, his diagnosis as of yet is that it is sticking valves, so right now its getting a valve job done and I hope to hear that the problem is gone when its done, I'll post when I know.
12-18-2009 | 06:20 AM
#23
Member
Joined: Jul 2009
Posts: 168
Likes: 0
From: Goldsboro, NC
Year: 2001
Model: Cherokee
Engine: 4.0
working out great so far... in town I leave my fan on all the time for stop and go traffic... other than that I leave my switch off and the computer controls the fan like normal... ran around a lot yesterday and started perfectly each time...
03-17-2010 | 11:30 PM
#26
CF Veteran
Joined: May 2009
Posts: 10,280
Likes: 4
Year: 1996
Engine: 4.0
TSB 18-031-03
Link http://www.wjjeeps.com/tsb/tsb_wj_1803103.pdf
Edit:
Whoa, just realized how old of a thread this was.
Link http://www.wjjeeps.com/tsb/tsb_wj_1803103.pdf
This bulletin is supplied as technical information only and is not an authorization for repair.
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 (90ºF)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.
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).
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE: 0.2hrs
FAILURE CODE:
AM Authorized Modification
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 (90ºF)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.
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).
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE: 0.2hrs
FAILURE CODE:
AM Authorized Modification
Edit:
Whoa, just realized how old of a thread this was.
Last edited by 89Laredo; 03-17-2010 at 11:32 PM.
03-17-2010 | 11:37 PM
#27
Member
Joined: Jan 2009
Posts: 140
Likes: 0
Year: 2001
Model: Cherokee
Engine: 4.0
Tey do make heat blankets for header found at advance auto or any parts store. a little easier than wrapping, and but almost as good.
03-17-2010 | 11:40 PM
#28
Junior Member
Joined: Feb 2010
Posts: 50
Likes: 0
From: Havelock, NC
Year: 2001
Model: Cherokee
Engine: 4.0
do what the tsb says on wj jeeps as stated in the previous reply it absolutely works I promise you I have a 2001 with 76000 miles it happened i ordered this stupid 6 dollar part from the dealership and followed the directions on wjjeeps and it worked like an absolute charm. Dont waste your time and money on some monkey fan. That tsb says it all. This is where i found my answer read what the first reply says and follow it and I promise it will work. good luck man. let me know if it does, i am positive it will.
http://answers.yahoo.com/question/in...7211854AAUixJV
http://answers.yahoo.com/question/in...7211854AAUixJV
03-21-2010 | 06:53 AM
#29
Thread Starter
Junior Member
Joined: Nov 2009
Posts: 54
Likes: 0
From: nj
Year: 2000
Model: Cherokee
Engine: I6 4.0L
i ran a bottle of chevron with techron through my jeep. been good ever since. was misfiring about every 2-3 wks. ran the FI cleaner through and its been lik 2 1/2 months since the last time it misfired. probablly just jinxed myself by posting this. its a little pricey but try it and let us all know how it worked.
07-05-2012 | 11:54 PM
#30
Newbie
Joined: Jan 2012
Posts: 2
Likes: 0
From: New york
Year: 2000
Model: Cherokee
Engine: 4.0L inline-6
I have the same problem except now I ordered a head thinking it was cracked.... But if this. An be fixed with insulation I'll just do that... But now I'm peranoid and see the oil pressure going down to 20 at idle after engine is good'n hot bit 50-60 while driving 