Sudden power loss

Allan M Jul 3, 2019

  1. Allan M

    Allan M New Member I am in great_britain

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    Hi.
    2001 d4d. Holding a steady throttle, 2000 rpm at 50mph passing through roadworks (every day!) The revs will without warning drop to tickover. They will come back up to 2000 rpm if i put my foot down but lacks power. Normally lasts a few minutes. No fault lights. Changed the SCV's a few weeks ago. Could this be a TPS issue? Getting more frequent.
     
  2. Bob

    Bob Well-Known Member Supporter I am in ireland

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    Sounds like a sensor if you have the scv's done, but would have thought a sensor would throw a fault. SCVs tend to cause more of a hold at certain revs.

    I'm also a bit confused as to how an engine drops revs suddenly when the clutch is engaged.. revs related to road speed surely
     
  3. Allan M

    Allan M New Member I am in great_britain

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    Automatic. Revs drop like I've taken my foot off the pedal.
     
  4. AndycruiserguyLomas

    AndycruiserguyLomas Well-Known Member I am in england

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    Sounds like a TPS issue to me. Although I've never had it on a Cruiser I had the same symptoms on our Yaris TD. I took it off and blew it out with the air line and the problem has never returned.
    I'm not saying this is your problem but you could try it as a cheap attempt.
     
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  5. Bob

    Bob Well-Known Member Supporter I am in ireland

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    Ah, that makes sense.. Autos are a mystery to me.. carry on.
     
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  6. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    Does Techstream work for the 1kd Collies? Just wondering if it’s worth looking at the reading for the TPS to see what’s coming out of it. Bit of a bu66er while it’s intermittent I’ll agree. Or just give it a clean and see, my tv engineer uncle always used to swear by graphited penetrating oil on carbon track pots but I’m not sure if that’s the method of sensing used by the TPS.
    It’s the lack of power bit that’s puzzling me. If it were just the TPS, then surely it would either pick up where it left off or be intermittent depending on the actual position. Probably worth testing it with a meter if it is a carbon track pot in there. It may have a crack or a worn out spot if the lions share of the miles were at that position, I.e. motorway miles. It could be lack of earth or a loose earth I suppose, or even a bit of corrosion creeping in somewhere.
    One of those where it would be great to borrow one for a few days and see what happens.
     
  7. diggerdave

    diggerdave Well-Known Member

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    Intermittent obstruction to the fuel pipe? Blocked filter, rusty tank, air getting in through deteriorated supply pipe (on top of the tank is the favourite grot spot) and occasionally causing an air lock? Blocked filter sock in the tank?
     
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  8. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    I had ruled this out because of the drop to idle rather than simply losing power but it could be a combination I suppose.
     
  9. MarkW

    MarkW Well-Known Member I am in morocco

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    TPS issue should result in engine warning light coming on. Worth getting the codes read, you can bridge a couple of pins in the diagnostic port and the codes are displayed in the dash. Can’t remember which pins you bridge though
     
  10. Shayne

    Shayne Well-Known Member Guru

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    Air in the fuel line , pipes coming off the tank are known to rot out .
     
  11. AdventureWagon

    AdventureWagon Active Member I am in australia

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    4 and 13 I believe. If you google you can find lists of codes.
     
  12. AdventureWagon

    AdventureWagon Active Member I am in australia

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    Is it like the petrol 90 and has a throttle cable. If not could it be the pedal sensor (APP)?
     
  13. AdventureWagon

    AdventureWagon Active Member I am in australia

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    The rev drop thing is standard on these older autos.
     
  14. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    Sorry, TPS = throttle position sensor.
    Great minds think alike! :)
     
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  15. Bob

    Bob Well-Known Member Supporter I am in ireland

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    1KD engine is fly-by-wire, so electric gremlin is possible
     
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  16. Allan M

    Allan M New Member I am in great_britain

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    Can anyone near me read the fault codes? I bought a cheap obd2 reader then found out i needed techstream. Sent it back and got techstream software and a cable. Installed on the laptop but it doesn't connect. I need to find out if its something I'm getting wrong or a problem with the obd2 plug.
    I need to solve this as the power loss is getting much more frequent.
    Main stealer is the last resort.
     
  17. StarCruiser

    StarCruiser Well-Known Member Supporter Guru I am in uk

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    Post up a thread for Techstream help Allan, or have a search for Techstream on here. There’s a fair few guys know their way around it. I’m sure someone will be able to help, they just may not find it buried in this thread.
     
  18. AdventureWagon

    AdventureWagon Active Member I am in australia

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    Did you try just shorting those 2 pins and counting flashes? Don't know about UK OBD2 requirements but in Australia it wasn't required until 2007 and most Toyotas from before then don't have it.
     
  19. Allan M

    Allan M New Member I am in great_britain

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    Latest update. I work with a mobile mechanic and he has just tried both of his expensive code readers and neither will talk to the car. Next step is to start pulling apart connectors to check and clean them.
     
  20. AdventureWagon

    AdventureWagon Active Member I am in australia

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    Modern scan tools won't work here. Unless you have the Toyota mOBD gear shorting the pins I mentioned and counting flashes is the only way.
     
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