Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee - WJ > Troubleshooting/Problems

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #25  
Old 04-20-2012, 03:21 PM
Member
My Jeep: 2002 4.7 HO WJ
 
Join Date: Apr 2012
Location: N Georgia
Posts: 41
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 775
WJ Fan is on a distinguished road
Re: 02 Overland- rough running at speed

Quote:
Originally Posted by FlyinRyan View Post
IIRC exhaust valves are also different.
I notice that you are a Fl-based vendor, FlyinRyan. I am in N Georgia. Do you have any recommendations for a shop to do either a head re-build or a full engine re-build? Perhaps you have one yourself?

There is no rush here- this is a project Jeep for me. But when I look through the factory manual that I have purchased as a PDF, my impression is that this is beyond my skill set. I have had quotes ranging from 300 - 400 per head, and $1000 for a re-built R head from Mopar (if one can even be had!). Another 600 to 1000 for the labor, risk that it may not be done correctly compounded by the quirks of the HO design, and this does not look like it makes sense to salvage this engine unless I can find another angle.
__________________

__________________
Reply With Quote
  #26  
Old 04-22-2012, 09:18 AM
Member
My Jeep: 2002 4.7 HO WJ
 
Join Date: Apr 2012
Location: N Georgia
Posts: 41
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 775
WJ Fan is on a distinguished road
Re: 02 Overland- rough running at speed

Here is the update, in case anyone is listening:

As of Sat AM, the Codes read
P0300 (M) Multiple Cylinder Mis-Fire
P0303 (M) Cylinder #3 Misfire
P0306 (M) Cylinder #6 Misfire


Coil testing seemed to indicate that some were intermittent, and at least one had failed, so I changed all for new.

Checked plug #6 (cylinder #6 had been the original code) and it appeared to have been firing, but was also wet. Checked plug #3 (misfire #3 and multiple cylinder misfire are new codes) and it appeared to be firing fine and was dry. Cleaned plug #6 and reinstalled all. Cleared codes by unplugging battery, truck seemed to run much better, took it down to town and got it smogged no problem (runs fine at idle).

To celebrate the good fortune (and see if this is sustained on a long freeway drive) took the wife out to dinner in downtown Atlanta, an hour drive each way. Truck ran rough at speed, got increasingly bad during the trip, and threw the same codes again (P0300, P0303, P0306). Even ran rough at idle once we had it down in ATL.

Watching the RPM closely, the rough running only occurs between 1800 and 2300 RPM. Unfortunately, this is the standard RPM range where it does most of the work while at speed.

The mechanic (who is indeed a Ford mechanic, as predicted), believes strongly that this is not a compression problem. His bias was the coil packs- hence my decision to replace all.

Based on what I have read on this and other boards, I am suspecting that this represents some PCM-based issue, most likely due to a sensor problem.

The three most likely candidates seem to be (in order)

1) chrankshaft sensor
2) Throttle position sensor
3) O2 sensor(s)

Any help, suggestions, comments would be most welcome!

Thanks in advance.
__________________

__________________
Reply With Quote
  #27  
Old 04-22-2012, 09:41 AM
FlyinRyan's Avatar
Senior Member
My Jeep: 2002 4.7L WJ
 
Join Date: Jul 2009
Location: Fort Myers, Florida
Posts: 2,797
Thanks: 33
Thanked 29 Times in 28 Posts
Rep Power: 87939
FlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond repute
Send a message via AIM to FlyinRyan
Re: 02 Overland- rough running at speed

Quote:
Originally Posted by WJ Fan View Post
I notice that you are a Fl-based vendor, FlyinRyan. I am in N Georgia. Do you have any recommendations for a shop to do either a head re-build or a full engine re-build? Perhaps you have one yourself?

There is no rush here- this is a project Jeep for me. But when I look through the factory manual that I have purchased as a PDF, my impression is that this is beyond my skill set. I have had quotes ranging from 300 - 400 per head, and $1000 for a re-built R head from Mopar (if one can even be had!). Another 600 to 1000 for the labor, risk that it may not be done correctly compounded by the quirks of the HO design, and this does not look like it makes sense to salvage this engine unless I can find another angle.
The only vendor I know in Georgia that I would trust and vouch for , would be Gerry Killian, from Killian Porting Service. I know he's done alot of these heads.

If you are talking about a rebuild, I would figure out a budget, and determine if you're looking to add any performance, or just do OEM. Theres vendors that sell 4.7 pistons etc, so a rebuild can be done. Really depends on what you want out of it, and what you're willing to spend.

I have had coil packs that have become wet with coolant get all sorts of weird on me like you describe.
__________________
Due to my workload, please do not PM me as I do not regularly check my PMs. Thank you :)
Reply With Quote
  #28  
Old 04-22-2012, 10:04 AM
Member
My Jeep: 2002 4.7 HO WJ
 
Join Date: Apr 2012
Location: N Georgia
Posts: 41
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 775
WJ Fan is on a distinguished road
Re: 02 Overland- rough running at speed

Quote:
Originally Posted by FlyinRyan View Post
The only vendor I know in Georgia that I would trust and vouch for , would be Gerry Killian, from Killian Porting Service. I know he's done alot of these heads.

If you are talking about a rebuild, I would figure out a budget, and determine if you're looking to add any performance, or just do OEM. Theres vendors that sell 4.7 pistons etc, so a rebuild can be done. Really depends on what you want out of it, and what you're willing to spend.

I have had coil packs that have become wet with coolant get all sorts of weird on me like you describe.
Thank you. I think that I will replace the sensors first, and then make a decision. The fact that it runs fairly well for 170K miles in open loop circuit (plus the intuition of my trusted, experiened- albeit Ford- mechanic) makes me think that the additional $200 +/- in cost for the sensors (DENSO O2, throttle position, crankshaft) plus my modest labor is the best way to proceed at this point.

If that does not do it, and I keep getting #6 cylinder misfire code and a wet plug, then I think that I revisit heads versus total re-build.

As to stock or performance, based on my other 2002 Overland which runs fine, I think stock has plenty of punch for my purposes- farm/city and occasional light towing when my 3500 dually is tied up with the big horse trailer.

Again, thanks for your assistance and advice.
__________________
Reply With Quote
  #29  
Old 04-22-2012, 10:12 AM
01grand's Avatar
Super Moderator

My Jeep: 2001 4.7L WJ
 
Join Date: Dec 2010
Location: Prior Lake, MN
Posts: 1,789
Thanks: 37
Thanked 59 Times in 58 Posts
Rep Power: 54179
01grand has a reputation beyond repute01grand has a reputation beyond repute01grand has a reputation beyond repute01grand has a reputation beyond repute01grand has a reputation beyond repute01grand has a reputation beyond repute01grand has a reputation beyond repute01grand has a reputation beyond repute01grand has a reputation beyond repute01grand has a reputation beyond repute01grand has a reputation beyond repute
Quote:
Originally Posted by TJXJWJ View Post
I don't like to belittle others...but to me there is just something inherently wrong with a turbo-charged PT Cruiser... My mind just can't compute that. All I keep picturing is grandma getting to the Discount Drug Mart in under 60 seconds.
Turbo charging is how you compensate for only having 4 cylinders! Lol not sure if I wish my wife's was turbo'd or not.


Sent from my iPhone using Tapatalk
__________________
Aaron

My Jeep: 2001 Grand Cherokee Limited, 245/65R17 Falken Rocky Mountain ATS, K&N drop in air filter, Bilstein HD's. De-badged, eagle-eye LED Tails & LED 3rd brake light, Addco front and rear sway bars, Superchips tuned & TM snip, interior 6k LED's, Gen3 ccfl projectors with Volt 6k HID lows, akebono brake upgrade with R1 Concepts premium rotors.
Reply With Quote
  #30  
Old 04-22-2012, 02:57 PM
Frango100's Avatar
The BEAST from Brazil

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,331
Thanks: 8
Thanked 32 Times in 31 Posts
Rep Power: 524727
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: 02 Overland- rough running at speed

If you have (access to) a scanner which shows life data, you can check the O2 sensors. The O2 sensor voltage should vary a lot, if one or more are at a steady value, then they are not working well. Also the upstream sensors are used for fuel trimming purposes (and cat efficiency), while the downstream ones are used for monitoring the efficiency of the mini catalytic converter only. So if you want to change them for trouble shooting, i would start with the upstream ones.
When you said that plug #6 was wet, it was wet with fuel and not with coolant or oil, right? Did you remove already the cylinder head cover to check the rockerarms on cylinder #6?
__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #31  
Old 04-22-2012, 05:07 PM
Member
My Jeep: 2002 4.7 HO WJ
 
Join Date: Apr 2012
Location: N Georgia
Posts: 41
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 775
WJ Fan is on a distinguished road
Re: 02 Overland- rough running at speed

Good feedback, thanks.

The scanner that I have access to only pulls codes- I will inquire about access to one that can provide live data.

Cannot say if the fluid on #6 was coolant or oil, but did seem to be more than fuel. What is odd is that the acceleration of the truck is quite brisk, and the idle is pretty good also. heading down the freeway, when it settles in to cruise at 60+MPH at about 2000 +/- 200 RPM is starts misfiring. Then when I accelerate, it seems to run fine.

I got a reasonable deal on the Denso O2 sensors, and have ordered all four.

Have also ordered remanufactured injectors. At 170K miles, and with a known failed coil on #6 (since replaced) that the prior owner had missed, and had kept driving the truck, I suspect fouling on that one, but all probably would benefit from remanufacturing. Paid $130 US shipped for all 8 with warranty.

Have not pulled the covers yet- what should I look for on the rocker arms?
__________________
Reply With Quote
  #32  
Old 04-22-2012, 06:06 PM
Frango100's Avatar
The BEAST from Brazil

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,331
Thanks: 8
Thanked 32 Times in 31 Posts
Rep Power: 524727
Frango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond reputeFrango100 has a reputation beyond repute
Re: 02 Overland- rough running at speed

It looks more an O2 sensor problem and i would wait with pulling the valve cover until you have replaced the O2 sensors. The right hand bank valve cover is not that easy to remove ( i can say it from my own experience).
But if you ever need to do it for further trouble shooting, you have to look at that the rocker arms are in place and without play. A dropped valve seat or bad lash adjuster can let the rocker arm fall of. It will simply lay somewhere on the head. In that case the respective valve will not open and cause the misfire. But it will probably cause a rough idle all the time as well.
I would only not expect a misfire on one or two cylinders only when the O2 sensor is at fault.
You are not loosing any coolant? There is no coolant in the oil?
__________________
Frank

JEEP Grand Cherokee 4.7 Lmtd 2004
HID 8000K in low and fog / Quad Squad member
Monroe Reflex shocks / Pirelli Scorpion ATR 245/65/17 - Transgo reprogramming shiftkit.

VW Beetle 2.0 TSI 2013
My new toy
Reply With Quote
  #33  
Old 04-22-2012, 06:40 PM
Member
My Jeep: 2002 4.7 HO WJ
 
Join Date: Apr 2012
Location: N Georgia
Posts: 41
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 775
WJ Fan is on a distinguished road
Re: 02 Overland- rough running at speed

Quote:
Originally Posted by Frango100 View Post
It looks more an O2 sensor problem and i would wait with pulling the valve cover until you have replaced the O2 sensors. The right hand bank valve cover is not that easy to remove ( i can say it from my own experience).
But if you ever need to do it for further trouble shooting, you have to look at that the rocker arms are in place and without play. A dropped valve seat or bad lash adjuster can let the rocker arm fall of. It will simply lay somewhere on the head. In that case the respective valve will not open and cause the misfire. But it will probably cause a rough idle all the time as well.
I would only not expect a misfire on one or two cylinders only when the O2 sensor is at fault.
You are not loosing any coolant? There is no coolant in the oil?
coolant loss- very interesting question.

I guess you are indirectly asking about warped heads from the overheating event? The original overheating event (months before I bought the truck) was apparently due to loss of coolant. When I purchased it, the coolant had dropped down out of the reservoir, assuming that at one point it was full. My initial hypothesis was a blown head gasket, and so one of the first things that I did was to test for exhaust gases in the radiator- and the test was absolutely negative.

I have changed the oil since owning it, and have closely monitored for fluid droplets in the oil- have never seen any.

In response to your query, have just checked coolant reservoir level (having driven it for 2h yesterday down to Atlanta)- no change.

Have not checked #6 spark today since the run yesterday- have had to work (on a Sunday...) taking a break now to check this board. Will probably pull that plug tomorrow and see whats what. My fear is oil, of course, potentially due to the valve sleeve not sealing after having popped out partially post overheating- which brings me back to the question of remanufacturing the heads.

At this point, the way I see it, at 170K, plugs, coils, fuel-related sensors, injectors, all probably need to be replaced anyhow. And I seem to be dealing with multiple simultaneous problems. There is absolutely no question that the Jeep is running much better than when I purchased it. In addition to various tests, what I have done is to change plugs (NGK Iridium), Oil (Mobil one synthetic 10 - 30 for high mileage), oil filter (Bosch), and all coils. And fixed the broken ground wire in the door and the blown mini-speakers in the dash...

Next week will be
1) throttle position sensor
2) O2 sensors
3) crankshaft sensor
4) all 8 fuel injectors

I also have the fluids in the transfer case and the two differentials yet to go- got the right stuff including the limited slip additives from the dealership. I doubt that these have been changed lately, if at all (many receipts for oil provided by prior owner, none for trans servicing or differential/T case fluids).

If you have any additional brainstorms, please do not hesitate to let me know!

Once again, my thanks.
__________________
Reply With Quote
  #34  
Old 04-22-2012, 06:52 PM
Member
My Jeep: 2002 4.7 HO WJ
 
Join Date: Apr 2012
Location: N Georgia
Posts: 41
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 775
WJ Fan is on a distinguished road
Re: 02 Overland- rough running at speed

Quote:
Originally Posted by Frango100 View Post
It looks more an O2 sensor problem and i would wait with pulling the valve cover until you have replaced the O2 sensors. The right hand bank valve cover is not that easy to remove ( i can say it from my own experience).
But if you ever need to do it for further trouble shooting, you have to look at that the rocker arms are in place and without play. A dropped valve seat or bad lash adjuster can let the rocker arm fall of. It will simply lay somewhere on the head. In that case the respective valve will not open and cause the misfire. But it will probably cause a rough idle all the time as well.
I would only not expect a misfire on one or two cylinders only when the O2 sensor is at fault.
You are not loosing any coolant? There is no coolant in the oil?
RE: running better- wife wanted some chocolate (yes, that time), and so I did a run to the local food and fuel, which provided a chance to jump on and off the expressway in each direction. Putting my foot into it, absolutely no problem smoothly running up to 5K RPM and hitting 80 MPH very quickly. Not the behavior of a sick engine. Hence my suspicion that I am dealing with a PCM/sensor and/or partially blocked injector issue.

AS they say, the proof of the pudding is in the eating. Careful on-line shopping will provide me with the sensors and replacement/remanufactured injectors at much less cost that throwing myself to the diagnostic mercy of the local dealership. And as an added benefit, I am learning, learning... with the help of this resource and contributors.

thanks.
__________________
Reply With Quote
  #35  
Old 04-22-2012, 06:52 PM
FlyinRyan's Avatar
Senior Member
My Jeep: 2002 4.7L WJ
 
Join Date: Jul 2009
Location: Fort Myers, Florida
Posts: 2,797
Thanks: 33
Thanked 29 Times in 28 Posts
Rep Power: 87939
FlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond reputeFlyinRyan has a reputation beyond repute
Send a message via AIM to FlyinRyan
Re: 02 Overland- rough running at speed

Be VERY careful when pulling the eclips for the injectors......The head castings and harness is such that if you drop one, it's lost in the abyss.
__________________
Due to my workload, please do not PM me as I do not regularly check my PMs. Thank you :)
Reply With Quote
  #36  
Old 04-22-2012, 07:13 PM
Member
My Jeep: 2002 4.7 HO WJ
 
Join Date: Apr 2012
Location: N Georgia
Posts: 41
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 775
WJ Fan is on a distinguished road
Re: 02 Overland- rough running at speed

Great tip, particularly for the amateur mechanic such as myself! I will try to meet expectations.

I am getting much more comfortable working around the engine, what with all of this on and off of coils, plugs, etc, and doing the plugs on both matching Overlands. But cylinder #8 is a bit of a PITA. I have to pretty much crawl into the engine compartment and take my watch off to navigate all of those cables back there under the dash and behind the throttle. And that little bracket combined with the ground cable.... A perfect set up to drop the nut that goes on top of the coil. But so far, so good.
__________________

__________________
Reply With Quote
Reply

Thread Tools
Display Modes

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 Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
03 liberty running rough need help! Sweetz77 Liberty-KJ and KK 5 10-26-2013 02:46 PM
Engine running really rough tkdgirl Troubleshooting/Problems 12 02-16-2012 06:06 AM
3.7 running rough, ideas? Cutthroat Grand Cherokee - WK 9 05-15-2011 09:05 AM
running rough snake678 Trouble Shooting/Problems/Service 1 04-10-2011 07:13 AM
jeep running rough Davie Troubleshooting/Problems 6 04-15-2010 07:39 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 11:50 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community