LS400 1UZ hard start problem

Discussion in 'General Discussion' started by Grady, Jan 29, 2018.

  1. Grady

    Grady Super Moderator

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    Hi Guys,

    Need some advice on a problem I have been having.

    I have recently completed a 1uz swap and the problem I am having is starting the engine when cold and warm (it tries to fire but fails), it takes around 6-7 times before it runs and idles.
    Once it's running and warmed up a bit it will idle perfectly for about 3-4 minutes then start dying so I have to press and release the throttle for it idle fine again.

    The car has been sitting inside the garage for the past month but it was running perfectly fine before then.

    Things I have done/checked so far:-
    • Replaced and gaped all spark plugs.
    • Replaced engine temp sensor.
    • Replaced O2 Sensors.
    • Fuel Pressure Checked and perfectly stable.
    • Checked resistance of all ignition-coil leads (resistance came back fine, but cannot rely on a resistance check).
    • Checked resistance on both coil packs (again resistance came back fine, but cannot rely on a resistance check).
    • Checked for Vacuum leaks over and over again and I am 100% sure there are none.
    • Checked ECU for any leaking capacitors (no visible leaks).
    The engine is a 1995 (non-vvti) (not-immobilized)

    Any suggestions would be appreciated.
     
  2. American Locomotive

    American Locomotive New Member

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    You likely have a stock idle valve. Very common problem.
     

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