ported abf throttle body woes

Discussion in 'Throttle bodies & non-OEM ECUs' started by new2gti, Oct 11, 2021.

  1. new2gti New Member

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    I replaced old tb with used new one as the old one had aftermarket micro switch glued to the side

    ported the new out inlet side and matched on the other

    didn’t go mad and go up to the butterfly, kept it 5mm back both sides

    engine doesn’t like it at all
    car will tick over from cold but as soon as throttle is touched it cuts out and won’t start after

    ive now taken the working switch off the new and put it on the old tb and all good

    any ideas why this may be happening

    any help appreciated :)



    [​IMG]
     
  2. Tristan

    Tristan Paid Member Paid Member

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    Sounds like the switch is out of adjustment?
     
  3. TonyB Paid Member Paid Member

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    That's not a micro switch its a TPS if its an ABF (throttle position sensor). It senses where butterfly is in relation to the throttle pedal and tells the ECU so it can work out where the crank and pistons are etc, so it can set the fuel and ignition accordingly.

    As you can guess if its set wrong it will mess everything up, and same if its not working at all, it will throw everything out.

    Are you running an aftermarket ECU? What was the aftermarket TPS for? Maybe the wiring had been altered to match?

    Porting the TB will have so little effect on power/torque, I wouldn't worry too much, if the old one works then fine, plenty of other things to do that will have far more benefit.
     
  4. rubjonny

    rubjonny Administrator Staff Member Admin

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    so you mean the idle switch? if so, what about the throttle position sensor, have you tested that
     
  5. new2gti New Member

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    haven’t tested the throttle position sensor only the micro switch which is good

    I did check check the wiring as a new plug was fitted for the micro switch and all good there

    thanks for the reply’s
     
  6. rubjonny

    rubjonny Administrator Staff Member Admin

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    yeah I'd say the tps has probably gone then :)
     
  7. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    If the car does not start, replace the throttle body with the old one. Start the car. If the engine fires up, good.
    Remove the TPS and fit to the target throttle body with the porting.
    Start the car. If it starts all good. Adjust the idle cam that has the throttle switch for idle. You want to adjust this, so that after a blip, the engine deaccelerates in a dashpot then come finally settles to ~ 800 to 900 rpm if on a Digifant 3.x ECU.
     
  8. new2gti New Member

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    thanks for all the replies

    in the end it was a broken wire on the coolant temp sensor

    when I first swapped the tb’s over all seemed good but after a short drive the following day it was back to running rough

    swapping the tb’s over must of moved the wire so there was some connection there [8-}]

    broken wire sorted and ported tb is on and running sweet

    thanks all
     
  9. Toyotec

    Toyotec CGTI Committee - Happy helper at large Admin

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    Excellent.

    Rule of thumb.

    ABFs either work or do not. If they do not, retrace your work steps [:D].
     

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