Engine loss of power (vanagon syndrome)

Discussion in 'T3 & T4 Tech Help Clinic' started by beerboy, Nov 21, 2011.

  1. beerboy

    beerboy Member

    Messages:
    504
    Location:
    Sydney
    Drive down the freeway fine come to a hill and lose power, drop a gear no difference, black smoke out the back. Power either returns or pull over power off and restart and off again until the next hill. Is this vanagon syndrome. I dont have a o2 sensor working, so I expect that isnt helping. But been running ok for a year. also doesnt idle very well. Amnything simple I need to look at :)
     
  2. gazman

    gazman Active Member

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    1,364
    Location:
    Perth WA
  3. beerboy

    beerboy Member

    Messages:
    504
    Location:
    Sydney
    thanks I saw that one was a bit sceptical about that one really. thought a knackered air flow metre or mechincal part
     
  4. syncro

    syncro Active Member

    Messages:
    5,702
    Location:
    Southern Highlands
    If it is Vanagon syndrome, you can switch off the engine for 10 minutes and when you restart, it will run fine.

    O2 sensor is not really needed.
     
  5. beerboy

    beerboy Member

    Messages:
    504
    Location:
    Sydney
    switched off and straight back on and ran fine. Be running ok for a year without the 02 sensor makes me think something else is at fault too
     
  6. syncro

    syncro Active Member

    Messages:
    5,702
    Location:
    Southern Highlands
    Could be Vanagon syndrome
     
  7. wbx4me

    wbx4me Member

    Messages:
    369
    Location:
    Melbourne south east
  8. wbx4me

    wbx4me Member

    Messages:
    369
    Location:
    Melbourne south east
  9. wbx4me

    wbx4me Member

    Messages:
    369
    Location:
    Melbourne south east
  10. beerboy

    beerboy Member

    Messages:
    504
    Location:
    Sydney
    "replace O2 and coolant temp sensor as well as the air flow box. problem persists"

    otherwise vanagon syndrome - looks like I have a bit of work to do
     
  11. wbx4me

    wbx4me Member

    Messages:
    369
    Location:
    Melbourne south east
    Vanders might take a look and tell us if he ever got to the bottom if it ....

    I'm thinking .....
    1) fuel quailty
    2) / water in fuel / clogged fuel filters (could be positional? like uphill .. more likely downhill though)
    3) wide open enrichment switch working correctly
    4) any shorts in O2 sensor leads (can they ground uphill)
    5 clean all EFI system connectors with contact cleaner
    6) unbolt efi box .. with it running shake EFI computer ..(does it have a positional / intermittent problem)?
    7) clean all grounds
    8) swap an AFM with someone else as a trial
     
  12. Grantus

    Grantus Active Member

    Messages:
    7,490
    Location:
    Southern ACT
    Vanders sold that bus soon after..... to me.

    It needed a new fuel pump & filter, along with some electrical corrections, from some poor PAID workmanship prior.

    eg, 02 sensor wire was simply stuffed into the base of a spade connector, and jammed on the contact...:wtf:

    Anyway, it didn't suffer the vanagon syndrome whilst here, and I think I sorted most of it's idiosyncrasies, before selling on, and is now owned by KC member Brian K. ;)
     
  13. BrianK

    BrianK Active Member

    Messages:
    6,645
    Location:
    Mount Gambier, SA
    Max now has the jumping and jerking issues and trying to stop etc and then has the fast idles going on as well. Have to start checking all vacuum hoses etc.
     
  14. beerboy

    beerboy Member

    Messages:
    504
    Location:
    Sydney
    Thanks for all the replies looks like I am not alone then. Not done it for the last few days again now. So I am thinking definately AFM and connections. Dont think its fuel as it runs rich without the o2 sensor and when it did lose power you could smell a strong smell of fuel and lots of black smoke which I think is more loss of spark than fuel
     
  15. syncro

    syncro Active Member

    Messages:
    5,702
    Location:
    Southern Highlands
  16. kombiwhisperer

    kombiwhisperer Member

    Messages:
    49
    Location:
    fraser coast queensland
    o2

    hey man, you need to replace that oxy sensor before you go any further, the vanagon ecu's were one of the first to run adaptive learn fuel maps, no or dodgey oxy signal gives low voltage which ecu sees as lean condition, and increases injection pulse to rectify.
    p.s. have had 2 do this, first one I spent 2 weeks on the ''#***^^THING
     
  17. syncro

    syncro Active Member

    Messages:
    5,702
    Location:
    Southern Highlands
    No, you can just disconnect it.
     
  18. beerboy

    beerboy Member

    Messages:
    504
    Location:
    Sydney
    you can disconect it but then it will run rich, mine only gets about 200 ks to a tank as I removed mine. ;-)
     
  19. syncro

    syncro Active Member

    Messages:
    5,702
    Location:
    Southern Highlands
    Only slightly rich. It is only a fine adjustment. If driven a few with them disconnected and it does increase the fuel consumption, but the performance is the same.
     
  20. roverbay

    roverbay Member

    Messages:
    501
    Location:
    nambour
    Gday all just read this the mates syncro was doing the same thing went local dealer to have fault found they didnt even look at it went to spare parts came back handed him the wire unit plugged it in a no further problems also they supplied it for free as part of recall process mind you that was a while ago
    Ernie
     

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