Hummer Forums by Elcova  
Forums - Home
Source Decals

Source Motors
Custom. Accessories.

H2 Accessories
H3 Accessories
Other Vehicles

H2 Source

H2 Member Photos
H2 Owners Map
H2 Classifieds
H2 Photo Gallery
SUT Photo Gallery
H2 Details

H2 Club

Chapters
Application

H3 Source

H3 Member Photos
H3 Classifieds
H3 Photo Gallery
H3 Owners Map
H3 Details
H3T Concept

H1 Source

H1 Member Photos
H1 Classifieds
H1 Photo Gallery
H1 Details

General Info

Hummer Dealers
Contact
Advertise

Sponsored Ads
















 


Source Motors - custom. accessories.


Go Back   Hummer Forums by Elcova > Hummer H3 Discussion Forums > Technical Discussion and Customizing your H3

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 08-24-2008, 07:43 AM
hawaiih3 hawaiih3 is offline
Elcova Rookie
 
Join Date: Aug 2008
Posts: 7
hawaiih3 is on a distinguished road
Default P0300//mulitiple misfire

1st time check engine came on was while I was in line at a drive thru so I ran a scan with a Gynesis and pulled P0303 and P0300 so I replaced all plugs
with iridium (denso)-cleared codes and ran another scan. No codes. However, the scanner can run live data stream and as I am running live data I can see mulitiple misfires and it records the count in history on each plug . But the misfires only occur during idle and not under load like cruising speed on the highway. for instance if i rev the engine like just tapping the throttle I can feel a hesitation of power and the live data reads mulitple misfire but then clears it self but no code or engine light comes it just continues to count and clear its self. I checked for a vacume leak found none, checked to see is the valve cover to intake box hose was cracked or loose and it wasn't. I replaced the # 3 coil, but still no change. There is no crankshaft sensor code nor camshaft sensor code, starts fine and runs fine but when I run live data I can see the misfires occuring. Anybody have any ideas on what is going on or lead me to possible cause?

JJ
Reply With Quote
  #2  
Old 08-24-2008, 03:10 PM
RubHer Yellow Ducky's Avatar
RubHer Yellow Ducky RubHer Yellow Ducky is offline
Hummer Guru
 
Join Date: Dec 2005
Location: In a FREE U.S.A. where Marxism, Socialism & Communism is not allowed !
Posts: 5,485
RubHer Yellow Ducky is an unknown quantity at this point
Default Re: P0300//mulitiple misfire

Dirty fuel, fuel filter, vacumn leak, gap, timing...

let us know...
__________________
REMEMBER
History, be it in 1 Year, 10 Years, a Hundred Years or One Thousand, will show that those people who voted for John McCain in the United States Presidental Election of 2008 were true patriots...
Reply With Quote
  #3  
Old 08-24-2008, 07:17 PM
Big Dad's Avatar
Big Dad Big Dad is offline
Hummer Guru
 
Join Date: Sep 2007
Location: In my prime....
Posts: 2,549
Big Dad is an unknown quantity at this point
Default Re: P0300//mulitiple misfire

What year is that beast and what engine do you have?
__________________
Alaska...If it's brown it's down!

Reply With Quote
  #4  
Old 08-24-2008, 08:14 PM
hawaiih3 hawaiih3 is offline
Elcova Rookie
 
Join Date: Aug 2008
Posts: 7
hawaiih3 is on a distinguished road
Default Re: P0300//mulitiple misfire

Thank you for your input:


I have the 2006 H3 3.5L/L5 engine. Prior to code pop up I used Chevron fuel but always fill up with Philips 76, I did check for vacume leaks didnt find one ( I checked the air intake tube, the air box and the valve cove to air box hose), I just put in new iridium plugs and I did check the gap they were .043 (pre-gapped) which is where they should be but I went ahead and regapped them to .041 just to make sure but no change at all,I havent tried the fuel filter. The rpms on the live data stream show from 611 to 634 at idle it is not a smooth a steady graph reading and did find that to be odd. I have appr. 46k miles with no major mods except the K&N filter which I had in there about 1 1/2 years with no issues, and only use regular unleaded ,every once in awhile i do give her supreme but never had light pop up.
TY
JJ

Last edited by hawaiih3 : 08-24-2008 at 08:52 PM.
Reply With Quote
  #5  
Old 08-24-2008, 09:28 PM
RubHer Yellow Ducky's Avatar
RubHer Yellow Ducky RubHer Yellow Ducky is offline
Hummer Guru
 
Join Date: Dec 2005
Location: In a FREE U.S.A. where Marxism, Socialism & Communism is not allowed !
Posts: 5,485
RubHer Yellow Ducky is an unknown quantity at this point
Default Re: P0300//mulitiple misfire

time to buy a new one...!
__________________
REMEMBER
History, be it in 1 Year, 10 Years, a Hundred Years or One Thousand, will show that those people who voted for John McCain in the United States Presidental Election of 2008 were true patriots...
Reply With Quote
  #6  
Old 08-24-2008, 11:47 PM
Ryan Graham Ryan Graham is offline
Hummer Veteran
 
Join Date: Mar 2008
Location: Syracuse, UT
Posts: 60
Ryan Graham is on a distinguished road
Default Re: P0300//mulitiple misfire

Head/valve problem? You'll have to do a compression and leak down test to verify. I had a P0300 and the dealership did an injector cleaning. The code hasn't come back, but the intermittently rough idle is still there.
Reply With Quote
  #7  
Old 08-25-2008, 12:13 AM
RubHer Yellow Ducky's Avatar
RubHer Yellow Ducky RubHer Yellow Ducky is offline
Hummer Guru
 
Join Date: Dec 2005
Location: In a FREE U.S.A. where Marxism, Socialism & Communism is not allowed !
Posts: 5,485
RubHer Yellow Ducky is an unknown quantity at this point
Default Re: P0300//mulitiple misfire

I bet then did not clean the fuel/injector system completely...

If you have any crap in your tank and it gets into the injectors .......

You need an ASS HOLE to ELBOW !!!
__________________
REMEMBER
History, be it in 1 Year, 10 Years, a Hundred Years or One Thousand, will show that those people who voted for John McCain in the United States Presidental Election of 2008 were true patriots...
Reply With Quote
  #8  
Old 08-25-2008, 05:08 AM
hawaiih3 hawaiih3 is offline
Elcova Rookie
 
Join Date: Aug 2008
Posts: 7
hawaiih3 is on a distinguished road
Default Re: P0300//mulitiple misfire

Thank you Ryan for your advise. As a matter of fact just this morning I introduced a fuel injector cleaner in the system it runs a bit more firm and I can feel a stiffer pedal I may have to introduce another bottle and see how that goes. I just ran a live data stream test but I think I might have one very dirty injector # 3-- keeps coming up on the live data stream, however, there is no check engine light coming on. Either I do a -on engine-fuel injector cleaning with the system or remove them and have them cleaned.
TY

JJ
Reply With Quote
  #9  
Old 08-26-2008, 01:27 AM
Hunner's Avatar
Hunner Hunner is offline
Hummer Professional
 
Join Date: Sep 2006
Location: Arkansas
Posts: 363
Hunner is on a distinguished road
Default Re: P0300//mulitiple misfire

Have the dealer run your vin and see if yours was in the batch that had poorly hardened valve seats or guides or both or whatever they did wrong. That might be it. Those are all the symptoms and they will not go away if that is it. It usually shows up before that many miles "if" that is the problem.
If so,
Attached Images
 
__________________
Traded 06 I-5 for 08H3 ALPHA/Adv,WarnPowerPlant9500,Warn 9000ti rear,Steelcraft brush/winch mt,RockyRoadrails/Hunner mod,GMUCP,Hunner rear/shock skids,OEM roof lights,Rola rack,2GoLights,Hunner steering gear mount,Purple Cranium diff guard,BulletProof tie rods,ARBsnorkle, SyKlone prefilter,Hunner intake pipe.

Last edited by Hunner : 08-26-2008 at 05:00 PM.
Reply With Quote
  #10  
Old 08-26-2008, 02:02 AM
Ryan Graham Ryan Graham is offline
Hummer Veteran
 
Join Date: Mar 2008
Location: Syracuse, UT
Posts: 60
Ryan Graham is on a distinguished road
Default Re: P0300//mulitiple misfire

If you narrow it down to a fouled injector (either by swapping with an injector from a cylinder with no misfires or injector balance test) then I would probably just replace it. I say this not knowing how much an injector for the H3 is, but I haven't had very good luck cleaning injectors. Please keep us informed as to what you find
Reply With Quote
  #11  
Old 08-26-2008, 04:11 PM
Desert Dan's Avatar
Desert Dan Desert Dan is offline
Hummer Expert
 
Join Date: May 2005
Location: Southern California
Posts: 829
Desert Dan is an unknown quantity at this point
Default Re: P0300//mulitiple misfire

I'd say it is the cylinder head!

Take it to the dealer and get it fixed if that is the problem.
__________________
Desert Dan

H3 2006 Adventure/Lux/5-speed/sunroof/rock rails/underbody skids/block heater/Boulder Grey/ Defender Roof Rack

Jeep TJ Rubicon 2003
1988 Jeep Cherokee

Gone - But- Not Forgotten 4x4's
1994 Jeep YJ
Toyota 4x4 Truck(s)
1970 Jeep CJ-5
1962 Willys Wagon
Reply With Quote
  #12  
Old 08-26-2008, 04:58 PM
Hunner's Avatar
Hunner Hunner is offline
Hummer Professional
 
Join Date: Sep 2006
Location: Arkansas
Posts: 363
Hunner is on a distinguished road
Default Re: P0300//mulitiple misfire

Like Ryan said, get them to do a leak down check. That was how they confirmed my problem. They have done several at the small dealership I go to.
__________________
Traded 06 I-5 for 08H3 ALPHA/Adv,WarnPowerPlant9500,Warn 9000ti rear,Steelcraft brush/winch mt,RockyRoadrails/Hunner mod,GMUCP,Hunner rear/shock skids,OEM roof lights,Rola rack,2GoLights,Hunner steering gear mount,Purple Cranium diff guard,BulletProof tie rods,ARBsnorkle, SyKlone prefilter,Hunner intake pipe.
Reply With Quote
  #13  
Old 08-26-2008, 11:31 PM
hawaiih3 hawaiih3 is offline
Elcova Rookie
 
Join Date: Aug 2008
Posts: 7
hawaiih3 is on a distinguished road
Default Re: P0300//mulitiple misfire

Update::

I have introduced the fuel injection cleaning solution in the system, actually several bottles (gradually) and I can feel a better/stiffer pedal. I run the live datastream while I am driving and all cylinders show "0" misfires count. While I let the engine idle I show no misfire count on any of the cylinders but # 3 (before that it was all of them)but I must say that they are very few now, not as before. I believe I just had very dirty fuel injectors(especially #3). Overall engine performance has been great even before I noticed anything, usually with a misfire error the engine idles very rough but not in this case. If I have never ran a live datastream test I would never know there was an issue, usually most folks run a scan to check why the check engine light has come on. I will be keeping an eye on this and see what happens. I am very hesitant to take it to the dealer because I have bad service in the past ( another issue for another day)and I don't trust them and the bad thing is that here only dealer here in Hawaii.

Thanks to everyone with your input.

JJ
Reply With Quote
  #14  
Old 08-27-2008, 01:09 PM
RubHer Yellow Ducky's Avatar
RubHer Yellow Ducky RubHer Yellow Ducky is offline
Hummer Guru
 
Join Date: Dec 2005
Location: In a FREE U.S.A. where Marxism, Socialism & Communism is not allowed !
Posts: 5,485
RubHer Yellow Ducky is an unknown quantity at this point
Default Re: P0300//mulitiple misfire

Quote:
Originally Posted by RubHer Yellow Ducky
I bet then did not clean the fuel/injector system completely...

If you have any crap in your tank and it gets into the injectors .......

You need an ASS HOLE to ELBOW !!!

BTW....as I reread my comment I ment to say "AN ASS HOLE TO ELBOW SYSTEM Cleaning"

Hope you didn't take offence at my lack of completion....
__________________
REMEMBER
History, be it in 1 Year, 10 Years, a Hundred Years or One Thousand, will show that those people who voted for John McCain in the United States Presidental Election of 2008 were true patriots...
Reply With Quote
  #15  
Old 08-29-2008, 02:36 AM
Ryan Graham Ryan Graham is offline
Hummer Veteran
 
Join Date: Mar 2008
Location: Syracuse, UT
Posts: 60
Ryan Graham is on a distinguished road
Default Re: P0300//mulitiple misfire

I actually didn't understand it but knew from your other posts that you didn't mean any harm so I just skipped over it
Reply With Quote
  #16  
Old 09-15-2008, 02:12 AM
hawaiih3 hawaiih3 is offline
Elcova Rookie
 
Join Date: Aug 2008
Posts: 7
hawaiih3 is on a distinguished road
Smile Re: P0300//mulitiple misfire

Hello,
Just here for an update on the mulitiple misfire (P0300) that I was dealing with; after about 3 weeks the of running the vehicle with STP (black bottle)(ran a bottle every other fuel tank fill-up) the check engine light has not returned. So, the issue was clocked fuel injectors, I am sure a good high pressure injector cleaning might be helpful as well but the STP bottles helped alot. Initially I ran 2 bottles of that stuff with a half tank helps in getting a less diluted product thru the injectors, no harm will come to your engine, the company also reccomends or at least suggest that it is okay to combine other STP products if so desired. Thanks to all that assisted or advices on my issue.
Have a nice day!
Reply With Quote
  #17  
Old 09-15-2008, 02:18 AM
RubHer Yellow Ducky's Avatar
RubHer Yellow Ducky RubHer Yellow Ducky is offline
Hummer Guru
 
Join Date: Dec 2005
Location: In a FREE U.S.A. where Marxism, Socialism & Communism is not allowed !
Posts: 5,485
RubHer Yellow Ducky is an unknown quantity at this point
Default Re: P0300//mulitiple misfire

SEE !!!

I knew you needed that A** H*** to Elbow !!!
__________________
REMEMBER
History, be it in 1 Year, 10 Years, a Hundred Years or One Thousand, will show that those people who voted for John McCain in the United States Presidental Election of 2008 were true patriots...
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
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

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 09:44 PM.


Powered by vBulletin Version 3.0.7
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.