Join Date: Oct 2007
Location: Nairn , Highland, Scotland, U.K.
2003GT Tickover Speed/ECU/TPS
As a very recent purchaser of a 2003 GT having come from an 1100RS, I was delighted to find this site to obtain loads of invaluable information about my new purchase. I have been particularly pleased to read the various bits of info regarding ECU/Cold start issues,as it was a big concern when I first got my bike, but having found that it is a peculiarity of this model and, with the help of other contributors, I was able to greatly improve the situation by re-setting the Throttle Position Sensor to the ECU. However I wonder if anyone has ever tried re-positioning the TPS after having done the re-set to try and fool the ECU into thinking that the throttle is open more than it actually is and thereby delivering more fuel, i.e. giving a richer mixture. Most contributors seem to think that the ECU mapping is set to give very lean running and a look at the colour of the sparkplugs confirms this.
As someone who has grown up on carburettors, like the nice old Amals on my Norton Commando,I confess to being somewhat out of my depth with fuel injection but all of the characteristics of my bikes tickover/small throttle opening faults would have had me reaching for a screwdriver to turn the air screw in half a turn. The faults are :- 1) The tickover is too fast at 1100rpm ( sometimes up to 1300rpm)
2) Throttle pick-up when cold is very flat.
3) There is some misfiring on small throttle openings when trickling along in the lower gears.
Does anyone know how to slow the tickover down ? I have checked all the cables for free play, and you can hear the butterflies closing with a metalic click, but onto what?? There's no stop screw for them. There's one for the cruise control cut-out micro-switch which had me fooled for a while !
Speaking of Cruise Control- When I turn mine on, the bike surges slightly. Disengage it and switch it in again, no surge. Is this normal ?
Finally, a safety issue !! Have a look at your back brake resovoir feed pipe. Mine was clipped to the pipe from the master cylinder with a plastic clip which held it out such that it was being rubbed by the swinging arm. This action had rubbed through the pipes rubber sleeving and, if left in this position, would have eventually rubbed through the hose itself !!
Any thoughts would be much appreciated particularly on re-positioning the TPS to improve all my slow running gripes. Oh ! and if anyone knows how to cure the " Box of Rocks" tickover rattle, I would love to cure that too.