Jump to content

Vortec 5.3 Spark Plug Colors

josef47
 Share

Recommended Posts

josef47 Enthusiast

josef47

Posted
Posted

My silverado from 2011 has now run 100000 mls. I changed the spark plugs 300 miles ago. Now i looked at the plugs again. One of the plugs, the one from cylinder 6 is black. All the others are clean. The engine doesn't have any problems. No oil consumption absolutely nothing it hasn't always done. Does anyone have any idea why the plug from cylinder 6 looks so completely different? I am grateful for any hints

300km.thumb.jpg.9f128a33036df368920451e09cc143b2.jpg

richard wysong Senior Enthusiast

richard wysong

Posted
Posted

possibly partialy clogged injector. try a couple tanks of non ethanol fuel with Techron injector cleaner

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

 Cylinders 1,4,6,7 are AFM cylinders, so that may be a reason.

 

You could bore scope a few cylinders to see if they look the same. But I kinda agree, toss some seafoam in the tank or a fuel system cleaner to see if it helps. Obviously move that dirty plug to a different cylinder.

josef47 Enthusiast

josef47

Posted
  • Author
Posted

thanks for the food for thought .

Should the AFM be the cause, are there no alarms on the dashboard?

Will a failed cylinder not be displayed to me? 

mjm-1957 Enthusiast

mjm-1957

Posted
Posted

Look at the center electrode porcelin, its not straight and square like the others. I would replace that plug with a new one put it back in number six and run it for a while and then check again. We have been getting alot of defective AC delco parts right out of the box lately. Possibly a boot leg knock off counterfit  part.

  • Like 1
swathdiver Senior Enthusiast

swathdiver

Posted
Posted
8 hours ago, mjm-1957 said:

Look at the center electrode porcelin, its not straight and square like the others. I would replace that plug with a new one put it back in number six and run it for a while and then check again. We have been getting alot of defective AC delco parts right out of the box lately. Possibly a boot leg knock off counterfit  part.

So many counterfeit 41-110s that GM released new part number.  Chicom knockoffs have been wrecking engines left and right, don't use them unless bought from dealer, Summit, RockAuto, etc.  Lots of Chicom plugs sold on Amazon and ebay.

  • Like 1
josef47 Enthusiast

josef47

Posted
  • Author
Posted

Now i have tried the old spark plugs (50.000mls) i have cleaned them and drove 100mls. everything looks fine now. no black colour on spark plug no 6. Now i will buy again some new spark plugs. It looks like one of the new ones was junk. thank you, BR Josef   

richard wysong Senior Enthusiast

richard wysong

Posted
Posted

I'm curious as to why you pulled the plugs in the first place after changing them. did u have a misfire?

josef47 Enthusiast

josef47

Posted
  • Author
Posted

the reason is as follows. I had recently removed the spark plugs after 50000 miles. ( as a routine, no trouble) In doing so, i realized that the color of one of the 8 spark plugs was very light. There were also some small white spots on it. However, i was not sure from which cylinder i had removed it. I wanted to see how the new spark plugs looked after 300 miles. I found this one black spark plug. This was the beginning of my confusion. But now i see that everything is fine. It is probably only one of the new plugs that is not quite right. I am replacing it now. 

 

  • 1 month later...
Supreme Pizza Senior Enthusiast

Supreme Pizza

Posted
Posted (edited)

When I have an issues on one cylinder - I check the compression on that cylinder. (100lbs minimum for it to fire reliably). Then I swap the fuel injector, spark plug, spark plug wire, and ignition coil to another cylinder. If the problem follows the parts, then you know its either fuel, or spark. So then you move the injector again to the next cylinder, and see of the problems stays with the ignition parts or follows the fuel injector. Its just as effective as "throwing" new parts at the truck, but its free and much less time consuming. I tracked it down to being a bad spark plug and/or a bad spark plug wire on a PT Cruiser the other day (check engine light, accompanied by a P0303). I replaced them both just to save time. I had both on hand, so why bother testing any further. Then I cleared the codes, and it was good to go. Swapping injectors and coils around sounds hard to some people, but its not. You only need a couple basic hand tools and 10 or 15 minutes of time.

Edited by Supreme Pizza
josef47 Enthusiast

josef47

Posted
  • Author
Posted

thank you supreme pizza. that is a very good strategy. I will follow if i have got some trouble like this in future. best regards Josef

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
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

    342,782
    Total Members
    8,960
    Most Online
    ShowMeShooter1332
    Newest Member
    ShowMeShooter1332
    Joined

  • Who's Online   1 Member, 0 Anonymous, 5,964 Guests (See full list)

  • Latest Articles

  • Posts

    • Jsdirt
      2027 GMC Sierra: Official Discussion

      By Jsdirt · Posted

      I was around and remember that era very well, so I'm calling b/s on that statement. If they were that bad no police department or taxi company would've bought a single one ... but they were used in both services (and fire) for DECADES. They were bulletproof and proven. Even the early 21st century ones weren't too bad! The early models were legendary.   Mine is proof, but people like atlas are blinded by agenda and refuse to believe facts right before their very eyes.   Even decades after they were built, a new generation started driving them, posting all their builds and shenanigans on Grandmarq.net and Crownvic.net. The failures would show up then, since they all were deep past 100k-150k miles by that point, and younger drivers tend to be a little aggressive, especially with vehicles than can lay a one-tire fire for as long as you hold your foot in it. They've more than proven themselves over the decades.   The only thing that'll really take them out is road salt. The bodies and sheet metal were garbage. A victim of the cheapout FoMoCo and GM have been partaking in before then, and since.   Today it's the stuff that counts - the undercarriage that rots away first!    GMs Caprice was no slouch either. Reliable as a stone ax - the opposite of what they build now.    
    • Jsdirt
      2027 GMC Sierra: Official Discussion

      By Jsdirt · Posted

      Let me know how your vehicles do in 10 years. You don't know ******, kid. 😂    There's a reason that Panther platform was used as police, fire, and taxi service for DECADES ... long before you were born, apparently.
    • davester
      Disconnecting Battery

      By davester · Posted

      If your connector also has a big lever to get the connector on and off, you don't want to force the lever either way, as it becomes a bigger problem if you bust the lever or the mechanism it works.
    • davester
      Disconnecting Battery

      By davester · Posted

      It's just useful to disconnect the battery to prevent odd shorting out when unplugging/plugging stuff together.  I also  touch the two cable ends together (after disonnecting) to drain the small amount of stored battery energy in various modules.   I believe the main system where you need to be more concerned with, so you need to do the above and then wait some time, iss when you are working on the air bag system, to prevent inadvertent firing of the air bags.   The in-cab switches are just that, plain switches, it's generally not a problem to swap them in/out.  For my '12, I'll get an error message on the dash if I power up the truck w them unplugged, but that's it (power up= turn the ignition on).   The ITBC located above the spare tire is a computer that manages the trailer brake system.  That is probably more important to have the battery disconnected.  It does have to be programmed to the truck, either before or after it's installed, for it to work.  For my '12, I had a very hard time reinstalling the main connector to it (IDK if yours is the same or not), it turned out the silicon seal was jamming up, preventing it from going on all the way.  I finally got it fully installed by lubing the seal with a bit of dielectric grease, then it slid on and latched in place easily.
    • BCGM
      Remote Start Noise 2024 2500 HD Gas

      By BCGM · Posted

      JR ! I just got the truck back from the Dealership today . The technician did a cold remote start on the truck this morning and it made the noise . It was determined that it was a starter issue and replaced it under warranty . Of course   it did not make the sound after a new starter was put in because the truck was not cold . We will we see what happens tomorrow morning when I start the truck cold  . Keep tuned !   Oh I found a video on YouTube of a cold start and it did the same thing your truck and mine do , I will see if I can find it and post it up

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...