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Thread: Flat Spot between 4K - 5K

  
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    cwaigy's Avatar
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    Flat Spot between 4K - 5K

    I've got a flat spot roughly between 4000 - 5000 RPM that I'd like to get to the bottom of. It's fine up to 4K, a bit hesitant between 4K and 5K and then it picks back up again at 5K.

    It used to have a random boost and hesitation problem below 4K but I seem to have solved that by having the following done. (the above flat spot was still an issue before doing any of the stuff below so these haven't caused it.)


    • Change both Boost Solenoids.
    • Change the standard AFM for another standard one.
    • Change the turbo for a VXR one (as the seals were on their way out)

    Aside from the above I'm still running standard map and all other stuff is standard too.

    I'm thinking MAP or Lambda sensors may have been damaged by my old leaky turbo (although ECU lights not on)? Any other ideas?

    Cheers
    Craig

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    Enigma ???'s Avatar
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    Quote Originally Posted by cwaigy View Post
    I've got a flat spot roughly between 4000 - 5000 RPM that I'd like to get to the bottom of. It's fine up to 4K, a bit hesitant between 4K and 5K and then it picks back up again at 5K.

    It used to have a random boost and hesitation problem below 4K but I seem to have solved that by having the following done. (the above flat spot was still an issue before doing any of the stuff below so these haven't caused it.)
    • Change both Boost Solenoids.
    • Change the standard AFM for another standard one.
    • Change the turbo for a VXR one (as the seals were on their way out)
    Aside from the above I'm still running standard map and all other stuff is standard too.

    I'm thinking MAP or Lambda sensors may have been damaged by my old leaky turbo (although ECU lights not on)? Any other ideas?

    Cheers
    Craig
    Don't think it will be the standard VX map at all,if the lambda sensor or sensors have gone the dash should be like an Xmas tree if the bulb behind the dash is working the other thing that could make it do that is the ignition module £100 odd from VX

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    Enkidu's Avatar
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    What PSI are you running since fitting the VXR turbo? Also are you running the standard IC?

    Reason i'm asking is because I had that flat spot when I fitted my VXR turbo and I think the charge was getting to hot so I wound the actuator back 1/2 turn which cured it.
    Arden Astra GSI - Phase 3.5

    EDS Phase 3.5 288 BHP 340 FT/LB

    Inlet cam and Dbilas manifold.

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    montyfox's Avatar
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    Try swapping coil packs if you have a spare or spark plugs.

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    Not sure what boost I'm running, although the problem was still there before the VXR turbo was fitted, but I guess it might still be worth a look though.

    I've had the spark plugs changed for iridium ones to try and eradicate this problem but that didn't help either.

    Cheers
    Craig

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