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Easy and free fix for vz v6 engine miss (faulty ECU)

Discussion in 'VZ Holden Commodore (2004 - 2006)' started by 60HOM, Aug 10, 2013.

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  1. Aug 10, 2013 #1
    60HOM

    60HOM New Member

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    Hi everyone, this is my first post after following the site for awhile because my vz v6 developed a miss. Long story short it end up being a short in
    No.6 INJ circuit, it was going to cost me $900+ for the ecu and $200+ to configure it :/

    Being a mechanic myself I looked into it and found all I had to do was use one of the other INJ circuits to earth No.6 INJ, after splicing into INJ No.5
    the miss disappeared :) with trouble free driving sence. So if anyone else out there has the same problem and wants to save $1000+ then replay on this post and ill detail how the carry the fix out, only takes about 15mins.

    Cheers
     
    60HOM, Aug 10, 2013
    #1
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  2. Aug 10, 2013 #2
    99notout

    99notout Active Member

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    Yes please, if you have any diagrams or pictures that would be fantastic. Thanks for the offer! :beer chug:
     
    99notout, Aug 10, 2013
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  3. Aug 10, 2013 #3
    greenacc

    greenacc Searching for the billion

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    How did you diagnose it ?
     
    greenacc, Aug 10, 2013
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  4. Aug 11, 2013 #4
    60HOM

    60HOM New Member

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    To diagnose is easy.

    First disconnect each coil pack one at a time while the engine is running to find the missing cyl, replace that coil pack with another cyl's coil pack to see if the miss moves to that new cyl or stays in the same cyl.

    If the miss moves then your coil pack is faulty, if it stays then and the spark plugs are good then its your inj which means your ecu has dropped out that inj due to a possible short from that coil pack.

    Now to fix it without spending $1000+ on a ecu and tune

    1. locate inj harness connection at the rear of intake manifold left side
    2.if you look at the rear of the plug on the main harness side it should look like this.
    brown/white pink/black brown/blue green red
    yellow/black blue/black green/black

    Cyl No.s

    5 3 1 + +
    6 4 2

    3. Now lets say No.6 is missing, grab your test light and test No.6 wire but earth it on either the green or red power wires, the light should just stay on, you'll see after testing the other cyls that it should flash dimly.
    3.now just cut No.6 (yellow/black) wire on the main harness side the splice it into No.5 wire (brown/white). its always good to splice it to the cyl earlier in the firing order eg No.2 to No.1 or No.4 to No.3. Then start engine
     
    60HOM, Aug 11, 2013
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  5. Aug 11, 2013 #5
    99notout

    99notout Active Member

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    Wow thanks for the reply and suggestion. Just a question, would that mean that the dead injector that you just spliced into and earlier injector wireing would get its impulse and inject the fuel into the cylinder too early??
     
    99notout, Aug 11, 2013
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  6. Aug 11, 2013 #6
    60HOM

    60HOM New Member

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    Technically yes but no, your talking about a difference of about .01 sec at 4000rpm, it wouldnt really matter what injector the spliced into but I would just use the earlier injector because why not if your doing it.
     
    60HOM, Aug 11, 2013
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  7. Aug 14, 2013 #7
    diysv6

    diysv6 Member

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    Hi 60HOM,
    I really liked the way you got around the failed injector switching from the ECU on #6 cylinder. Does the extra switching current on INJ#5 transistor switch exceed the transistor's specifications, or is there a safe design margin in the ECU? Would you stay with this rewire in the long term, or look around for a good, reasonably priced second hand unit?
     
    diysv6, Aug 14, 2013
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  8. Apr 5, 2014 #8
    maxcol

    maxcol New Member

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    With your firing order the ++ are the drivers seat ?
     
    maxcol, Apr 5, 2014
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  9. Jun 5, 2014 #9
    vzladyowner

    vzladyowner New Member

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    Hi my vz has a miss and my mate who works for racq would really appreciate your knowledge on how to fix it for me
     
    vzladyowner, Jun 5, 2014
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  10. May 3, 2015 #10
    alloytec sludge

    alloytec sludge Member

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    engine miss

    i did this today to stop a constant miss and it worked yah
     
    alloytec sludge, May 3, 2015
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  11. May 3, 2015 #11
    MYVESSV8

    MYVESSV8 Well-Known Member

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    Sticky maybe or in the how-to's?
     
    MYVESSV8, May 3, 2015
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  12. May 9, 2015 #12
    alloytec sludge

    alloytec sludge Member

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    just here in this post
     
    alloytec sludge, May 9, 2015
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  13. Jul 7, 2015 #13
    roamin

    roamin New Member

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    Hello and thank you for the handy info.

    Currently i am having a injector issue on a vz that makes the car run terrible and also comes up on the dash with a check powertrain issue. I have an obd scanner which told me it was an injector circuit. When i meter across the wiring they all measure 8.5v but when i meter the brown/blue wire i get 1.2v so i take it thats my suspect wire.

    Does anyone have any check power train issues after cutting and splicing? Also did anyone else have a check powertrain issue leading them to this?

    Cheers
     
    roamin, Jul 7, 2015
    #13
  14. Jul 10, 2015 #14
    DarrylBarba

    DarrylBarba New Member

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    Gday mate...

    I am curious about how to suss out the misfiring issue.... I have a 2004-2005 model VZ wagon Exec... and a month ago it started to shake really badly when idling and up to the 80km mark... The mechanic who checked it says the ECU had **** itself and was the reason for the misfiring which had nothing to do with the Injectors. So after replacing the ECU it still had the shakes and even after replacing the spark plugs (which hadn't been changed since 2011) it still now has the shakes. I feel i have been "taken for a ride" as i have no bloody idea and trust in the mechanics knowledge... Originally the dash showed a warning sign saying Check Drive Train .. Cost me too much already i know this thread is from a while ago so i wonder if all is still running good in regards.

    Cheers
    Darryl
     
    DarrylBarba, Jul 10, 2015
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  15. Jul 11, 2015 #15
    Shadowstorm

    Shadowstorm New Member

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    Hi I am keen to do this , but what do you mean by splice? My faulty cylinder is the front right if standing in front of the engine ( is that 2? ) and if it is do I just pull out wire going to cylinder 1 cut the plastic back and do the same to the faulty wire , wrap them around each other than jam it back up where cylinder wire 1 was? And will this work fine ? Thanks in advance and sorry if I sound a little nieve but I can't afford anything as I live in Australia
     
    Shadowstorm, Jul 11, 2015
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  16. Jul 11, 2015 #16
    Shadowstorm

    Shadowstorm New Member

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    hi I'm keen a short vid or pic would be ace
     
    Shadowstorm, Jul 11, 2015
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  17. Jul 11, 2015 #17
    alloytec sludge

    alloytec sludge Member

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    try these splicers just make sure they splice through to the copper wire underneath
     
    alloytec sludge, Jul 11, 2015
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  18. Jul 11, 2015 #18
    alloytec sludge

    alloytec sludge Member

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    dam not sure how to send pics
     
    alloytec sludge, Jul 11, 2015
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  19. Jul 11, 2015 #19
    alloytec sludge

    alloytec sludge Member

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    try this see if it works
     

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  20. Aug 11, 2015 #20
    pete_pumpkin

    pete_pumpkin New Member

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    I just tried it after swapping coils around etc, confirming 6 is playing up. Spliced 6 into 5 aswell. Funny thing is 5 years ago I replaced coil 5. Anyhow it didn't make a difference. My elm327 doesn't seem to work either so maybe i'll buy a new one of them first before I go any further. I did buy a non contact vltage sensor but that didn't pick up anything on those cables.

    edit:

    Changed out injector 6, still same problem. Ordered a compatible obd2 scanner, should have it next few days.
     
    Last edited: Aug 13, 2015
    pete_pumpkin, Aug 11, 2015
    #20
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