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Thread: 4AGE 20v hesitates to rev beyond 2000

  1. #1
    Senior Member 4.5AG's Avatar
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    Default 4AGE 20v hesitates to rev beyond 2000 with video


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    Car:AE86 Trueno Silver Top Block with MAP and BT ECU, individual coils

    Problem:Engine refuses to go beyond 2000rpm on all gears, it splutters, quads back fires and pretty much hesitates to rev.

    Done so far, checked for vacuum leaks
    Replaced TPS
    Replaced Fuel Filter and new fuel in tank,
    Unhooked the O2 sensor and did not make any difference.
    Checked plugs and coils

    Cheers, Vener
    Last edited by 4.5AG; 3rd February 2013 at 06:45 PM.

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    Start by checking the alternator voltage and timing.

    Also let her warm up too
    Ae86 Drivingclub - Toyota AE86 Car Club where AE86 | KE70 | Toyota 86 / GT86 | Subaru BRZ | Scion FRS owners

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    Thanks Matt, I'll check the alternator.
    Timing is ok....
    Cheers,
    Vener

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    I took a video using my Go Pro and see if it helps, on :41,:55,:59,1:05, with light throttle(30%) and shifting below 3000 rpm from ist to 5th.
    then on 1:30 shifted down to 2nd gear with full throttle and the flat spot can be felt before 3000 and after that it revs and makes power.
    here's the link: camera is located behind the driver side head light
    Video to be uploaded soon
    Last edited by 4.5AG; 3rd February 2013 at 07:03 PM.

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    Here's a couple of things I've encountered with my 20v, they might be worth checking on yours, since I had similar issues to you.

    Knock sensor (someone had screwed in a random knock sensor on my block, if this is the case, you will get an engine check light)
    Fuel Pressure Regulator (mine was stuffed, did not hold the correct pressure in the rail)
    Fuel Injectors (2 out of 4 were dead, had to get them flow tested, and replaced)
    VVT pulley (mine was defective, and needed replacing)

    Fuel Injectors are really easy to miss, as you can't get a diagnosis from the ecu. I've been fooled twice on two seperate engines looking for the root cause elsewhere.

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    around 2000rpm is where the stock ecu fires up the VVT (might be a fraction less), you have timing or vvt issues with back fire thru the quads.

    Although im lead to believe when the vvt plays up or is broken it can make a terrible rattle.

    Any error codes on the ecu?

    So your only effected between 2000-3000rpm?

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    here's the video

    http://youtu.be/lusXUB5I0kw

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    Without vvt it would struggle up top....

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    how do you have the individual throttles wired with the stock ecu???

    backfiring through the intake and no revving is engine timing.......sounds like the timing is WAY out. Either mechanically or something is really advancing the timing cause early ignition.

    i know you said the timing was ok.......but from the sound of the fault it doesnt seem so

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    Quote Originally Posted by pizzaeater View Post
    Without vvt it would struggle up top....

    Incorrect.

    VVT is there to aid lower rpm torque and power, its turns off around 6-6500rpm from factory.

    Without VVT you have alot less low rpm power and torque till about 6000rpm then it evens back out again..

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