Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > Sport Touring: ST4 / ST3 / ST2 > TPS SETTING

[pcn1]

I made a start on checking the TPS yesterday. After removing the airbox I located the idle grub screw (located on the throttle body of the upper cylinder, quite tricky to get a allen key onto).
I then did a reference check on the mV signal at the computer plug, 390mV which although is not important lets me know a reference point.
So now Im thinking to myself, I'll back of the idle screw and check/set the exact 150mV signal I need, but whats this, the idle screw is backed out and the butterfly's appear shut tight !!!! As the bike starts and idles OK I am going to assume the air bleeds must be backed right out ??? The 390mV is the TPS reference point and the bike has run OK ??
This obvoisly is not the way to set the bike up but it appears that is the way it is. I have not progressed the job further as any I wanted a second opion that the obove setup would still allow the bike to run.
This is the bike I took to Sigma last October for a FIM chip that could not be made to work (engine "missing" all the time) and had to have the original chip put back. Neil said to me at the time that my TPS reading seemed strange to him, and I could not leave the bike behind for futher work.
I think I should now set the TPS to 150mV, close the air bleeds and open the idle screw to start the tuning process correctly.

Any thoughts ?

Thanks

[nelly]

There's a second throttle stop screw on the throttle body next to the cable linkage on the rhs of the bike.
If you've not backed this one out to, then the throttles won't be completely shut.
Set the idle with the the one you've found, then screw the other one in until it just touches the stop and alters the tps reading.
You'll also need to watch that the balance linkage isn't holding the rear throttle open because the front one is shut, as the linkage is virtually never equal.

[pcn1]

I think I have inspected that one already, its the fast idle adjuster isn't it ? I'll double check. The vacuum gauges should tell me if one butterfly is slightly open as visually it can be hard to tell. If its not to bloody cold I'll go into the garage tonight and check!

Thanks

[nelly]

There is the linkage for the fast idle there, but the throttle stop is a small grub screw in the actual casting that makes up the mounting bracket of the throttles. It'll have a blop of yellow anti tamper paint over it. It takes a 2.5mm allen key.

[pcn1]

Nelly,
I'm getting slightly confused here, the idle screw is on the linkage on the vertical cylinder throttle body (this is a grub screw and was covered in yellow paint) but you also say there is another throttle stop down by the fast idle screw ? Why is this here ?? (I have not looked at this yet, to cold out there !)

Thanks

[nelly]

Don't really know why it's there, it just is. I guess it's more a mechanical stop to prevent the linkage twisting after snapping the throttle shut several times???????
It will stop the throttles closing though despite you having backed the main/centre one out.

[pcn1]

Nelly,
OK, without that infomation I may have been in trouble, although the articles i've read on the net have not mentioned this before. Got the day off Friday and hope to complete it all then !

Thanks