TPS Adjustment - My Findings

Ok so today I have been able to test the results of the TPS adjustment I did at the weekend. Power delivery and throttle response is definitly smoother, not just at the lower rev range but right throughout the rev range. One word of caution, once you have done this adjustment you will only get engine braking with the throttle fully closed. I found it much easier getting the throttle balance right through bends, it wasn't the usual on or off snatchy power delivery. The reduced engine braking caught me out when approaching a bend a couple of times.

On the motorway cruising at *0 seemed more effortless, the engine was smoother and less throttle opening was needed.

One thing that I like about the SV is the low down pulling power it has, this adjustment has improved it even further.

One other benfit that may be gained from this is improved MPG especially on amotorway run, has anybody found this, or was it worse because you made use of the extra grunt

Tim

[TSM]

was this on a pointy or curvey?

[Stu]

I think he has a pointy.
I can't believe it is anything other than psychological benefit at other than low revs.
But it's good to know another one has only found positive benefits to it.

[TSM]

Originally Posted by Stu

I think he has a pointy.
I can't believe it is anything other than psychological benefit at other than low revs.
But it's good to know another one has only found positive benefits to it.

TPS if not calibrated properly can make for very bad running especialy at lower revs. A freinds TL was way off and it would realy make it run bad when trying to do any slow speed stuff.

TPS is diffrent to the TRE.

TRE works higher in the revs.

Originally Posted by Stu

I can't believe it is anything other than psychological benefit at other than low revs.

As far as I know all modern engine management systems have a throttle position sensor. This sensor does not just tell the fuel injection system when to start adding more fuel but it is also used to determine how much. The management system will be monitoring the quantity and possibly density of the air entering the engine and read messages from the TPS of what the rider/driver wants to do i.e go faster, stay at a constant speed or slow down. Hence the adjustment of this sensor is important for the whole rev range not just low revs. If incorrectly adjusted the fuel mapping for the engine can be completely wrong throughout the whole rev range.

On more complex system a knock sensor will be used, the ECU will use this information to constantly adjust the ignition timing for maximum effeciency. If the SV had one of these you would get the full benefit of fuels like Shell V Max.

Kind regards
Tim

[TSM]

The carbed bikes also have TPS, so i guess with them it adjusts the ignition timing.

Originally Posted by Stu

I think he has a pointy.
I can't believe it is anything other than psychological benefit at other than low revs.
But it's good to know another one has only found positive benefits to it.

The TPS works as a resistor. You pull the wire out, and it affects the resistance given, which tells the ECU (or other gubbins) what it's supposed to be doing.

Pull the wire further, you get a more accurate result due to the mechanics of the spring loaded resistor. I know this from a long time spent testing a hydraulic system that used this very system to tell how far the hydraulic jacks were extended. Fix the wire to 2 solid objects, with a yoyo spring one end, move the objects using the jack, get the resistance & translate this into distance. Pretty much what the bike does, judges distance that the throttle has moved.

With this in view, obviously if you move the TPS so that the wire is pulled sooner, it gets pulled further at every throttle position, and would give some benefit. How much, I'm not sure, and I haven't noticed it on my K6 with the TPS adjustment done.

[Stu]

Very now.
The TPS adjustment is adjusting when the line moves from the middle of the screen to the top. Which to me sounds like an on off switch.
What Baph says makes sense, but does not equate to the sensor having 2 positions IMO. Who is right?

The line moves when a certain resistance is met.

Does that help to clarify?

Originally Posted by Stu

Very now.
The TPS adjustment is adjusting when the line moves from the middle of the screen to the top. Which to me sounds like an on off switch.
What Baph says makes sense, but does not equate to the sensor having 2 positions IMO. Who is right?

OK. The TPS is definately not a switch. The ECU is programmed to respond to the voltage being returned from the TPS. The ECU needs to know what position the throttle is at, what movement is being made and how fast. The ECU will be programmed so that once a minimum voltage has been reached it will start injecting more fuel. This is what you are adjusting when setting the position of the TPS.

A carburettor is quite an effecient mechanical device but it does have it's limitations. Basically it is designed to react to the air being drawn through it and emit the right amount of fuel into the air stream being drawn through it.

With fuel injection the ECU has to determine when to start inecting fuel and for how long. This is no easy task. So much needs to be taken into account, engine temerature, engine speed, change in engine speed, intake air pressure, intake air temperature, throttle position, rate of throttle position change, direction of throttle position change.

Kind regards.
Tim