Jump to content

04 6.0 Random Miss Fuel Fowling Plugs

dragonrider

By dragonrider
in Ask A GM Technician

Recommended Posts

dragonrider Enthusiast

dragonrider

Posted
Posted

I have a 04 6.0 g3500 express 17ft 198,000 miles.this is a random miss only above 50 mph to start.Outside temp has to be above 45 degrees. because of my work it I have to run for 2 hrs,it gets worse,some times if I wind her up it will clear for a few miles.It will finally get to where it is at idle.If i shut down for a few minutes,some of time gets better.It seems to start when at cruise,low gas pedal,[high vaccunm?].It started with my thinking it was bad gas.I was bad about over filling it,didn't know it was a no no. Gm dealers said it had a miss cyl 3 and 7,and because it had non GM wire it was the wires.changed no difference.Then was told #8.then #4&2[ now have gas in oil going to change it] Now the shop foreman says he has had a lot of fuel pumps go out and with my miles thats proably whats wrong,but how does a fuel pump fuel fowl the plugs?I see what i think is fuel around the vapor cannister,but it looks dry tranny is there so when I smelled it could not be sure as it melted the under coat.I then ran truck 2 days with out the gas cap,ran great till I got on brakes real hard then hard excell,now its back.Again the only consistant thing is above 45 degrees out side temp.sorry for length but would rather give too much then too little info.please help i earn my living with this truck,$600 fuel pumps come dear Dragonrider

ChevyTech007 Enthusiast

ChevyTech007

Posted
Posted

I would replace the cannister. It is probably full of gas from over-filling. The purge valve is pulling the extra fuel from the cannister fouling the plugs. The purge valve is only turned on when certain conditions are met, that is why it does not alway happen. From now on, when the gas nozzle cuts off the first time...Stop filling.

dragonrider Enthusiast

dragonrider

Posted
  • Author
Posted

Ty for the reply,now a update.Running with cap off when hot helped,but scan showed #8 missing.Cleared codes then the weather changed,cap on [rainning] temp below 65 truck has not missed or set code.scan says IAT at 60 degree,before when it was 70 it showed 105.I am thinking the evap system caused problem,but maybe #8 has a problem [has new plug and wire.going to put can and control on,then if #8 only shows work on just it

  • 4 weeks later...
dragonrider Enthusiast

dragonrider

Posted
  • Author
Posted
Ty for the reply,now a update.Running with cap off when hot helped,but scan showed #8 missing.Cleared codes then the weather changed,cap on [rainning] temp below 65 truck has not missed or set code.scan says IAT at 60 degree,before when it was 70 it showed 105.I am thinking the evap system caused problem,but maybe #8 has a problem [has new plug and wire.going to put can and control on,then if #8 only shows work on just it
dragonrider Enthusiast

dragonrider

Posted
  • Author
Posted
Ty for the reply,now a update.Running with cap off when hot helped,but scan showed #8 missing.Cleared codes then the weather changed,cap on [rainning] temp below 65 truck has not missed or set code.scan says IAT at 60 degree,before when it was 70 it showed 105.I am thinking the evap system caused problem,but maybe #8 has a problem [has new plug and wire.going to put can and control on,then if #8 only shows work on just it

 

 

Update and answer.

I finally discovered that the wiring harness had rubbed a spot on the #8coil feed wire,also had rubbed injectore wiring.one small spot less then the size of a pin head.it would move because of bumps in road etc,temp was because the dipstick tube was the point or short,but in cold weather the harness was stiffer.just goes to show,OBD2 scanner does not always find the problems,you have to look and think

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    342,840
    Total Members
    8,960
    Most Online
    appletrav
    Newest Member
    appletrav
    Joined

  • Who's Online   2 Members, 0 Anonymous, 309 Guests (See full list)

  • Latest Articles

  • Posts

    • newdude
      2 speed transfer case optional now?

      By newdude · Posted

      This is a 1/2 ton thing ONLY.  All HDs 2020-2026 have the two speed transfer case, with Autotrac as an option.     1/2 tons 2019-2026, regular 4x4s come with a single speed case (no 4LO!), and trucks with Z71 ordered, or all Trail Boss trucks come with the 2 speed case.  2 speed case is also an option on WT, and is also standard on High Country.  
    • newdude
      Different requirements for oil filters?

      By newdude · Posted

      2013 5.3 still to this day calls for the PF48 filter.  Which as a 15psi bypass pressure.     There is a TSB, 17-NA-157 that talks about the PF-63 and PF-64 filters which have a higher bypass rating of 22psi.    TSB HERE - temp.xml   "Beginning in 2012, the oil pumps began to regulate main gallery feedback instead of pump out pressure. This means that the oil pump now does not begin to regulate until pressure is built up to the main gallery. This change reduces the amount of time it takes to provide oil to the engine bearing and lifters during extreme cold start conditions.  Main gallery feedback oil pump control systems are present on the following engine families which use Spin-on oil filters: Small Gas Engine (SGE), Large Gas Engine (LGE), High Feature (HFV6) Gen2 and Small Block Gen5 gasoline engines. These engines with the main gallery feedback oil pump control systems are factory built with an ACDelco® oil filters"   It also calls out what engines use those filters.  The gen 4 small blocks were not on that list (LMG, LC9, L9H, L92, L94, L20, L96).  Gen 5 small blocks use the higher pressure filter.          That all said...   Your 7045 Napa filter is the PF63 equivalent, with 22psi bypass.  You are already using the higher bypass pressure filter.  You CAN keep using it, you don't technically have to use it though.  
    • Grumpy Bear
      Different requirements for oil filters?

      By Grumpy Bear · Posted

      Do you know WHY the filter relief setting was increased to 22 psig?    When the new system goes into the second stage the pump volume ramps up considerably. It was found that the 15 psi filter bypass setting put the filter in bypass on a warm engine when the second stage was activated. Raising the filter bypass setting forced the filter to do what it designed to do. Filter. Preventing debris from circulating during high load, high rpm operation.    So next question is how did GM find this out? VLOM/lifter failures and a deep dive by Melling Corp.    Last question. Is it required? Look at it like this; a motor may be equipped with a rev limiter. But it only works if the set point in reached. That 22 psig setting only matters if the pressure differential across the filter media exceeds 15 psig during normal warm operation. Second stage kicks in around 3000-3500 rpm.    I can't answer your question because I don't know you and how you use the truck. But I think there is enough information here to let you decide for yourself. 😉
    • Coastie05
      give me some tips to make my truck look better

      By Coastie05 · Posted

      Go back to OEM wheels. 
    • newdude
      2020 Trailboss 6.2 replacement

      By newdude · Posted

      Probably not their first rodeo, so it should go as planned most likely.  Typically the service manager or tech doing the swap will put some seat time to shake it down after they get it all put back together.  We usually put 50-100mi before we hand them back so if something happens, its not after you get it.  A coolant leaks, oil leaks, a ground left off or loose, vibration, etc.     The new engines so far have been good?  There's been a couple that have popped out there again (the replacement engine) but most have been okay.  

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...