Go Back   Jeep Garage - Jeep Forum > Jeep Technical Discussion > Troubleshooting/Problems Discussion

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 08-29-2012, 04:08 PM
Member
My Jeep: 2006 3.7L WK
 
Join Date: Jul 2010
Posts: 36
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1485
michael 1970 is on a distinguished road
2006 Grand Cherokee code 0420

Hi All-
This past weekend I thought I would do a nice thing and clean and Detail my wifes car. I cleaned the engine as I have done numerous times before with Simple Green, taking care not to get the electrics wet.
Well the next day it started bucking, hesitating and tripped the MIL. Scanned it, found a random misfire. Pulled the coils, found moisture on 4 of them. Blew them off, sprayed with WD40, and blew off again. Blew out the wells where the plugs are, found a lot of water in # 2. put back together, still had a slight skip, cleared codes, reset the MIL.
Wife drove it the next day, a lot of hesitation and the mil came back on. Scanned and found # 5 cyl misfire. Pulled all coils, #5 had a little moisture on it, the rest dry. Replaced all plugs, blew out all wells again, reinstalled, reset MIL, took for a long ride, ran great!! nice and smooth.
Wife drove it again, MIL came back on, rescanned, got a code 0420- Catalyst System Low Efficiency
I have read that a faulty coil could cause this.
Does anyone have any Ideas?
Thank You.
__________________

__________________
Reply With Quote
  #2  
Old 08-29-2012, 05:56 PM
2005JGC's Avatar
Senior Member


My Jeep: 2005 4.7L WK
 
Join Date: Nov 2010
Location: Portland, OR
Posts: 2,751
Thanks: 51
Thanked 69 Times in 58 Posts
Rep Power: 1652901
2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute
I would just drive it for a while. Run it up and down the road at 3-4k rpms to get the cats nice and hot then just drive it normally for a week or so.

When you have a misfire it pumps raw fuel into the cat which just melts the cat down...

Sent from my SCH-I500 using Tapatalk 2
__________________

__________________
2005 Jeep Grand Cherokee - Gone but not forgotten!

Reply With Quote
  #3  
Old 08-29-2012, 07:01 PM
Member
My Jeep: 2006 3.7L WK
 
Join Date: Jul 2010
Posts: 36
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1485
michael 1970 is on a distinguished road
Re: 2006 Grand Cherokee code 0420

Thank you, you said it melts the cat down, is that as bad as it sounds? are the cats that delicate?
__________________
Reply With Quote
  #4  
Old 08-30-2012, 12:56 AM
2005JGC's Avatar
Senior Member


My Jeep: 2005 4.7L WK
 
Join Date: Nov 2010
Location: Portland, OR
Posts: 2,751
Thanks: 51
Thanked 69 Times in 58 Posts
Rep Power: 1652901
2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute
Quote:
Originally Posted by michael 1970 View Post
Thank you, you said it melts the cat down, is that as bad as it sounds? are the cats that delicate?
I'm not talking like make some toast warm, it gets HOT without the raw fuel... Typically they can take a bit of misfire abuse, but that is the reason the make the MIL flash. Because it cannot take a lot.

Sent from my SCH-I500 using Tapatalk 2
__________________
2005 Jeep Grand Cherokee - Gone but not forgotten!

Reply With Quote
  #5  
Old 09-03-2012, 11:14 AM
Member
My Jeep: 2006 3.7L WK
 
Join Date: Jul 2010
Posts: 36
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1485
michael 1970 is on a distinguished road
Re: 2006 Grand Cherokee code 0420

Hi guys-
Well, I think that the cat is gone. I had a friend of mine who is a toyota tech come over and scan and diag. the code, and it appears the o2 sensors are working fine, and the misfire did the cat in. The car has 116K miles on it so the cat was prob weak before, due to the # of miles, and the misfire did it in.
Does anyone know of a place I can get a new cat? I assume jeep only sells the whole front pipe w/ the 2 cats.
I am just looking for options and cost.
Thanks.
__________________
Reply With Quote
  #6  
Old 09-03-2012, 12:03 PM
2005JGC's Avatar
Senior Member


My Jeep: 2005 4.7L WK
 
Join Date: Nov 2010
Location: Portland, OR
Posts: 2,751
Thanks: 51
Thanked 69 Times in 58 Posts
Rep Power: 1652901
2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute
Re: 2006 Grand Cherokee code 0420

honestly your safest bet is the rediculously expensive Y pipe from Mopar, I have seen a number of people who replace the cat with an aftermarket then continue getting catalyst effiency codes. There may be some users on here that have had a cat replaced with good luck and maybe they can tell you what brand they used, but ultimately your going to need to call up a local exhaust shop and they will be the ones who cut out a cat and weld in a replacement.
__________________
2005 Jeep Grand Cherokee - Gone but not forgotten!

Reply With Quote
  #7  
Old 09-03-2012, 06:28 PM
Member
My Jeep: 2006 3.7L WK
 
Join Date: Jul 2010
Posts: 36
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1485
michael 1970 is on a distinguished road
Re: 2006 Grand Cherokee code 0420

That was what I was thinking also. My tech buddy said he has replaced some cats w/ aftermarket units, and has had some troubles w/ reoccurring codes after a couple years. He says to try to go w/ the factory units, but if $ is an issue, then get an aftermarket unit w/ a lifetime warranty, so if there is any problems down the road, at least the part will be covered. He has returned some units for replacements.
Hopefully some other members here have gone thru the same issue and can give some advice regarding aftermarket units.
__________________
Reply With Quote
  #8  
Old 09-05-2012, 08:15 PM
Member
My Jeep: 2006 3.7L WK
 
Join Date: Jul 2010
Posts: 36
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1485
michael 1970 is on a distinguished road
Re: 2006 Grand Cherokee code 0420

Well. I was able to find the OEM Y pipe from a online dealer, which is actually in my area, for $899, and no need to pay the ridiculous shipping charge for it. My next question is: do I need to remove the transmission crossmember to replace it, or is there enough room to drop the front of the pipe and slide it out before the rear of the pipe pivots up and hits the underside of the floor.
Thanks
__________________
Reply With Quote
  #9  
Old 09-06-2012, 12:55 AM
2005JGC's Avatar
Senior Member


My Jeep: 2005 4.7L WK
 
Join Date: Nov 2010
Location: Portland, OR
Posts: 2,751
Thanks: 51
Thanked 69 Times in 58 Posts
Rep Power: 1652901
2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute2005JGC has a reputation beyond repute
The cross member must come out. Just fyi, the collector hardware can SUCK... Make sure to get some penetrating lube on them early and ALWAYS tighten them some before loosening them!

Sent from my SCH-I500 using Tapatalk 2
__________________
2005 Jeep Grand Cherokee - Gone but not forgotten!

Reply With Quote
  #10  
Old 09-11-2012, 06:11 PM
Member
My Jeep: 2006 3.7L WK
 
Join Date: Jul 2010
Posts: 36
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1485
michael 1970 is on a distinguished road
Re: 2006 Grand Cherokee code 0420

I should prob replace the o2 sensors while I have it apart. Should I go OEM, or aftermarket?
__________________
Reply With Quote
  #11  
Old 09-12-2012, 12:41 AM
Frango100's Avatar
Premium Member

My Jeep: 2004 4.7L WJ
 
Join Date: Dec 2009
Location: Brazil
Posts: 4,644
Thanks: 9
Thanked 54 Times in 52 Posts
Rep Power: 525441
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: 2006 Grand Cherokee code 0420

Jeeps normally donīt like Bosch O2 sensors, because they heat up too slowly and give related fault codes.
OEM is best, which is in fact Denso.
__________________
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
  #12  
Old 10-26-2012, 05:23 PM
Member
My Jeep: 2006 3.7L WK
 
Join Date: Jul 2010
Posts: 36
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 1485
michael 1970 is on a distinguished road
Re: 2006 Grand Cherokee code 0420

Hello again-
I have not had the opportunity to replace the cats yet- trying to save some money. But I did have something odd happen regarding this issue. Over the last couple weeks, the check engine light would go off on occasion. It would go off, stay off for 1 to 2 days, then come back on. I scanned it for codes when it was off and the p0420 was still there, however there was not a pending code. When the light is on, there are 2 of the same codes, one of them being "pending"
Is this normal? I thought that the check engine light would come on, or go off after 3 driving events of either a problem or no problem.
I was thinking about changing the o2 sensors on the bank that has the issue to see what happens.
I thought that a cat either works or not. It seems that it is working from time to time (thus turning off the CEL) or not(turning it back on).
What do you think??
Thanks.
__________________

__________________
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
2006 Jeep Grand Cherokee po700 code Midnightrida Troubleshooting/Problems 7 03-09-2014 10:56 AM
07 grand cherokee CRD p0101 code airmail96 Export & Diesel Powered Jeep Models 0 07-12-2012 09:55 AM
2005 4.7 WK Code P 0420 bsw989 Troubleshooting/Problems 1 07-10-2011 03:40 PM
2006 Grand Cherokee davidw Grand Cherokee - WK 3 12-28-2009 09:03 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 11:45 PM.


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