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Adapted from Chewy's "how to..." 07/11/2004
Q: What does it do??
A: The TPS senses what revs the engine is running at and then
'instructs' the fuel injection and engine management systems to make
adjustments (basically to start squirting more or less fuel into the
cylinders). MOST bikes are set wrongly and this causes the bike not
to run smoothly at low speeds (due to the fact that there's not
enough fuel getting into the engine & then all of a sudden the fuel
starts pumping in faster but by then it's a bit late!!) This
adjustment rectifies the problem!
Throttle Position Sensor (TPS) Adjustment
Step-By–Step Guide
**Before undertaking this task I strongly recommend that you
read the instructions through from start to finish and have them to
hand during the process.
You will need:
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1) You will need to make your diy ‘dealer mode
tool’…
Simply take a piece of wire about 3 inches
long and strip back about 8mm of the insulating sheath (twist
the cores together on multi-core cable). Snip off the last
2-3mm with a pair of scissors or a wire cutter to leave a
clean end. |
2) Undo the side panels
under the saddle…
And remove the seat…
3) Undo the tank retaining bolts…
Lift the tank & prop up with the tank prop (surprisingly!!)
4) Run the engine until at it’s normal operating temperature (most
are around 85-90 degrees – I plump for 86!!)
5) Check & adjust your idle speed… It should be about 1200rpm.
6) If (as above) the idle is too low, locate the
idle adjust screw – on the left hand side of the bike in one of the
triangular recesses in the chassis and adjust. Turn clockwise to
raise the idle speed and anti-clockwise to lower it… Go in small
movements and ‘blip’ the throttle after each adjustment and allow it
to settle before trusting what the rev counter says!
7) Undo & remove the pillion seat. 8) Locate the
Dealer Mode Activation Connector
If you look into the tail unit from behind, on the left hand side
you should see a bunch of a few wires & connectors behind a bit of
plastic protruding from the undertray.
Follow this bit of plastic down towards the rider’s saddle and you
should find another connector. It’s rectangular, white plastic with
6 holes for connectors in and only 4 of them used. It also has a
black rubberised cover on it.
9) Turn off your ignition and put your ‘dealer mode tool’ in
the two terminals that are next to each other.
**WARNING**
Do NOT short out the wire onto the chassis or any other part of the
bike. Do NOT connect either of the other two terminals to anything.
10) With the ‘tool’ still in the connector turn on your ignition.
The temperature display should have disappeared and now you will see
a little line (like a minus sign), the letter c followed by two
zeros. If you have any other numbers shown in this display there is
a fault (it’s the dealer diagnostic display!)
11) Start your engine and SLOWLY turn the throttle while looking at
the little line on the dash… It should move from the middle of the
zeros to the top at about 1450rpm. I will bet money on the fact that
it won’t!! It will probably move at about 3000rpm.
This is where the fuel injection starts injecting more fuel into the
engine so when it’s set too high the bike will be jerky at low
speeds! (The line takes a second or two to move, hence turning the
throttle slowly!) 12) Turn off the engine and
locate the Throttle Position Sensor… It’s under the tank on the left
hand side of the bike, just behind the air box.
13) Using your size 25 Security Torx bit…
CAREFULLY undo the two torx bolts on the sensor (the ones at the top
& bottom, not either side!).
**WARNING**
The bolts are very hard to get to (especially the lower one) and are
made of a very fine, soft French cheese!!!!
I found it easiest to adjust if you don’t undo the top bolt very
much as this way you can pivot it a bit better!
14) Start the engine and turn the sensor anti-clockwise (I think) to
decrease the sensor’s activation point. You will need to make very
tiny movements of the sensor!
You may find that the engine cuts out (or nearly cuts out). If it
does stop, try moving the sensor back in the opposite direction &
thumbing the starter button again. If this doesn’t help, try
increasing your idle speed a little at a time until the engine
starts & runs properly again!
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15) Keep making small adjustments, turning the throttle slowly while
looking at the display to see when the line moves to the top of the
display. It should stay in the middle of the display whilst idle and
move to the top at around 1450rpm.
Keep fiddling – it does happen although it can be bloody fiddly &
infuriating!
NOTE: It takes a couple of seconds for the display to show the
change once you move the TPS so you have to be a little patient...
16) Once you’ve got the line to move
at about 1450rpm, very slowly tighten up the bolts on the sensor
again – it’s easiest to do the top one first. It’s not a bad idea to
hold the sensor steady as you tighten it as if it moves, the sensor
will activate at a different rpm! Check that the line moves at the
same revs after you tighten each bolt. 17) Remove
the ‘tool’ from the connector, replace the rubber cover, tuck back
where you got it from and check that the temperature display returns
on the dash!! 18) Put the tank back down, replace
your saddle, side panels and pillion seat and go and test!!!
Note for PCIII owners:
by TLRMan - Once you set the TPS against the bikes calibration, you
then set the TPS calibration on the PCIII. This way they are in
Sync.
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