GSX-R1000 K1 (2001) Throttle Position Sensor (TP) hack (16/10/2005)

Apparently, this is a "batch fault" with the 2001 GSX-R1000's.

My "TP" sensor started failing at the start of the year. I blamed it on poor tuning, bad fuel, cold mornings, bad suspension, bumpy roads and bad riding etc. After a thorough tune-up at 30 grand (and to no avail), I got a tip off from JeffW of gixxer.com (thanks a million mate !, you're a bloody legend ;).

The TP sensor has a funny style connection to the throttle drive.. So the throttle drive can only apply a turning force to the TP in one direction only. The TP therefore relies on a spring to return it to a lower position. What happens is that the "o-ring" inside the TP sensor swells up.. so that when the throttle turns the TP sensor, the TP will not spring back (see o-ring pictured below)--

The bummed output voltage of the sensor seems to confuse the ECM (Electronic Control Module)-- When you close the throttle, the ECM still thinks you have it open.. therefore it cuts the motor (it didn't analyse exactly what it does-- whether it cuts the ignition or cuts the injectors-- one of the two anyway).

These were my symptoms (and common with this fault)--

  • "Bike dies after a high rev (twist and then remove your hand from the throttle)" [1]

  • Open the throttle right up in 2nd gear (or any gear) up past 9 grand, drop it off a fraction (5% of a full twist), and it's like you have cut off the throttle completely.


    • I rang up Peter Stevens here in Adelaide (our local Suzy Dealer), and they wanted $180 for a replacement !!. Like, fuck me dead man !!!!!!!!!!!!!!!!!. I nearly chocked when they told me that.

    Electrically, The TP sensor is simply a (passive) 5K ohm linear variable potentiometer. Dick Smith sell "Pots" for about $1.60--

    http://www.dse.com.au/cgi-bin/dse.storefront/4351feca0d4569bc2741c0a87f9c0757/Product/View/R7553

    If you want a good quality one, then Farnell sell them for between $10 and $60--

    http://uk.farnell.com/jsp/endecaSearch/searchPage2.jsp?Ntt=5k+potentiometer&newSearch=true&Nto=potentiometer&Nty=1&showImages=true&N=401&Ntk=gensearch

    This gives you an idea of just how ridiculous the $180 asking price is-- It's day light robbery.

    As a temporary fix (and to verify the fault), I repaired (dodgyed) my TP sensor. Basically, I removed my TP sensor from the throttle value. Cracked it open with a stanley knife, identified the problem, removed the o-ring, and glued it back together (epoxy resin). This fixed fault.

    I'm now working on building my own TP unit, sourcing cheap parts (watch this space). Here are some pics of the finished hack--

    For anyone with this fault, then I hope this saves you from throwing away your hard earnt $$$$$$.


    --
    Jason Nunn (aka-- USENET alias "Fred Kroft")


    [1] Jeffw, "Re: 01GSXR1k running problems?", www.gixxer.com
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