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VY Commodore 3.8l V6 Backfire on Idle

Discussion in 'VZ Holden Commodore (2004 - 2006)' started by Halon, Aug 14, 2019.

  1. Halon

    Halon New Member

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    Hi Guys

    My VY commodore 3.8l V6 Has a Backfire on Idle issue. I have changed Fuel Filter, Plugs. Coil pack is working fine, but have not changed leads as yet.

    However while checking i found that When the car is in Idle & Backfireing if i dissconnect the MAF sensor there is NO change..... The car still runs ....not even a slight change in revs.... is this a Faulty MAF? & is this issue consistant with the backfireing fault ?

    Any Help will be much appreciated.
     
  2. Halon

    Halon New Member

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  3. losh1971

    losh1971 Well-Known Member

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    Kmart scan the PCM and BCM for $45 and they normally get you in, in day or two.
     
  4. Halon

    Halon New Member

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    losh1971 likes this.
  5. losh1971

    losh1971 Well-Known Member

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  6. greenacc

    greenacc Searching for the billion

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    Can't you check a VY without a scanner?
    You might have a faulty TPS. My Ecotec used to backfire when trying to accelerate when the TPS was stuffed.
     
  7. Halon

    Halon New Member

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    Update:


    I re-set Fuel consumption average & drove the car for 20mins. On completion the reading was 68L/100km… before it was 11.5L/100km… so running very Rich. Then I set the dash display into Diagnostic mode to check Instantaneous fuel consumption…. That reading was over the roof…. So yep… she is running Rich.

    There could be many issues. I suspect the MAF….. The computer not detecting correct airflow & is running the car rich which is its Protection mode. Ordered new MAF, new Leads, Plugs & O2 sensors…. Will see how that goes.
     
  8. Halon

    Halon New Member

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    Update:

    The new GM Plugs will be in today so i have loosend the plugs on the car getting ready for the new ones. I removed 2 plugs just to check them as i had Cleaned & gapped them a few days ago. And Yep.... the plugs are wet & you can smell the fuel on them.

    So the issue with the car is that it is Definitely running Rich. New Plugs & leads won't Solve that issue, But the new MAF & O2 sensors might fix it hopefully.

    Any Ideas ?
     
  9. Halon

    Halon New Member

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    If you set the dash on the VY into Diagnostic mode you can get some information & work from that…but in general they would need Scan tool & software. SRS codes need Tool & software to Clear them after fixing any issues.
     
  10. Halon

    Halon New Member

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    Update:

    The MAF & new plugs arrived, installed them. but issue is not Fixed still running rich.will waiting for the O2 sensors & new Leads. I don't think that will make any deference. so back to Square 1.

    apart from the computer what else can make the car run Rich ?
     
    Last edited: Aug 16, 2019 at 2:54 PM
  11. greenacc

    greenacc Searching for the billion

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    That is mega rich so more likely a defective part I'm guessing. Like fuel injector or fuel pressure regulator that's stuffed and just dumping fuel into the engine. But TPS still a likely culprit too. Get it scanned for codes ASAP.
     
  12. Halon

    Halon New Member

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    Update:

    Checked TPS this morning no issue with that.

    Just a heads up....I am in Darwin, I know a Scan will tell me the errors, most people i know only have OBD2 scanners (a mate gave me one but they dont work). The mech shops want a fortune just to Scan it. After a heart attack i am on a sickness benifit they won't let me work so i don't have the cash to splash. To make matters worse i have constant Cardiology & other appointments at the Hospital as well. Just spent a heap of cash getting stuff this week. next pay i might purchase the Cable & software from "Envyous Customs". will see how i go.

    Thanks for your help God Bless you.
     
  13. Halon

    Halon New Member

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    I have had more persons willing to help me with suggestions on a different forum. My friend warned me NOT to waste my time with “Just Commodores Forum”……. I guess he was right.

    Thanks so much to the 2 persons that responded to my thread and tried to help me.

    Cheers & all the best.
     

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