Back firing in intake when accelerating under load

Discussion in 'General Discussion' started by 500H V10, Nov 10, 2023.

Car Parts
  1. 500H V10

    500H V10 Full Access Member

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    I'm not sure what's causing this there is no codes present but back firing inside intake when accelerating under load
     
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  2. Michael from the U.K.

    Michael from the U.K. Active Member Supporting Member

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    I had that one time,I think my harmonic balancer was dodgy,not sure tho but it was something like that.
     
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  3. rottenronnie

    rottenronnie Well-Known Member Supporting Member

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    Do a leakdown test (not just a simple compression test) to isolate a cylinder that may have a leaky valve.

    If all the cylinders are holding air (passed the leakdown test), then a leaky injector or an ignition issue (coil or plug) is next on the list.
     
    Last edited: Nov 10, 2023
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  4. VIPR PWR

    VIPR PWR Full Access Member

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    Did you do any work on the truck ? Plug wires crossed , burnt ?
     
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  5. 500H V10

    500H V10 Full Access Member

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    I'm thinking of checking the fuel rail pressure though maybe my fuel pump starting to go I would think I would get a code though if it was low fuel pressure. Everything is untouched.
     
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  6. 500H V10

    500H V10 Full Access Member

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    The engine idols very smooth and under light acceleration it runs very smooth with no misfire only under heavy acceleration does it randomly backfire in the intake manifold
     
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  7. VIPR PWR

    VIPR PWR Full Access Member

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    Intermittent misfire .. possibly weak or damaged plug or plug wire . I know I had a plug the the electro was bent and off center and cause it to intermittently misfire on mid range acceleration . Plug wire break down in high temperatures or get burned from the exhaust and can send spark to a ground area it’s close to or touching .. try opening the hood in the dark ,, no lights around and see if there is any arcing from the plug wires or coil packs . when my plug was misfiring I did get a code though !
    eliminate the easy stuff then move on to the next . Some of the problems that cause that stink ..
     
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  8. 500H V10

    500H V10 Full Access Member

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    I'll check under the hood later tonight for any arcing. Thanks!
     
  9. VIPR PWR

    VIPR PWR Full Access Member

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    You can also check using an ohm meter on each plug wire to see if any are broken down on the inside .. yes the wires are a pain in the butt to get to under the intake manifold .
    Why the hell did they put the coils there . Still nobody that I know of has relocated the coil packs out from under the manifold ..
     
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  10. Michael from the U.K.

    Michael from the U.K. Active Member Supporting Member

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    More fun for us if you put your hand on the wires tho.:D
     
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  11. VIPR PWR

    VIPR PWR Full Access Member

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    Hahaha ,, helps you bounce a bit doing that …
    In the old days with customers hanging on the fenders while we worked on cars ,, we always kept a charge ignition condenser sitting on the fender cover .. if they got to nosey we asked them to hand it to us hahahaha ZAP !

    years ago I wanted to test out the sparking of my new MSD ignition system .. supposedly fired like 20 times per cylinder revolution .. I believe they were right hahaha ZAP ZAP ZAP ZAP at 40k volts per ZAP hahah
     
    Last edited: Nov 12, 2023
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  12. Wifey

    Wifey Well-Known Member

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    To funny!
     
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  13. THEWELSHM

    THEWELSHM Well-Known Member Supporting Member

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    seen my coil packs 3 times in 3 months, hope I don't see them again for a while. those back inlet bolts suck to get at.

    thewelshm
     
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  14. VIPR PWR

    VIPR PWR Full Access Member

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    I’ve heard and read that .. I’ve never had to or even wanted to pull the damn intake ,,,,Stupidest design I’ve ever seen .
     
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  15. rottenronnie

    rottenronnie Well-Known Member Supporting Member

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    The adventure really begins when you strip the upper Intake bolt on #9.
     
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  16. VIPR PWR

    VIPR PWR Full Access Member

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    :eek: That can’t be fun
     
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  17. Wifey

    Wifey Well-Known Member

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    Try it ??? :p
     
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  18. VIPR PWR

    VIPR PWR Full Access Member

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    I’ll send the truck to you and you can move my coils to a easy access location :p:D
     
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  19. rottenronnie

    rottenronnie Well-Known Member Supporting Member

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    There is only one bolt that is a bit of a challenge when removing the Intake (#9).

    Like everything, once you've done it a few times, there are tips and tricks to make the job easier/faster.

    I'm still wondering how grasshoppers and bees (well, what's left of them) end up behind the coil packs.
     
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  20. Wifey

    Wifey Well-Known Member

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    Bees are amazingly resilient!!
     
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