Re: [ST] Sooty suggestions?

[Andrew Tait <antait@xxxxxxxxxxxxxxxx>]

Hi Chris,

Chris Harwood wrote:

[...position reset of idle air valve on power on...]

> I have seen it do a 'down to the bottom and back to somewhere' check on
> switch-on.  There's no positional feedback so it relies on assuming that
> each pulse-set results in a one-step movement.

Well, it's up to the top and back, but I'll let you off :o)

> I guess the ECU may bang it into the endstop to ensure it knows where it
> is!

 From my observations, at ignition on, it moves the valve to the very 
top until it judders, then takes it back down about 5mm.  At ignition 
off, it moves the valve almost all the way back up to the top.  The 
number 'judder' steps are obviously very small, as if you start the 
valve at the very bottom, it takes around 3-4 on/off cycles for it to 
actually reach the top.  I wonder if this is the source of poor running 
after a stall for example?

Anyway, the bikey is now running perfectly!  Given that all I've done is 
remove clean and refit the plugs, and clean the idle air valve, I'm 99% 
sure the idle air valve's soot was to blame.  I now wish I had taken 
some pictures, but I did the strip and clean after a 10 hour day at 
work, and my brain was in reverse.  Well, neutral.  Brilliant weather 
here in sunny Scotland this weekend, so I've done nearly a tankful of 
miles since yesterday morning.  Hell, if it wasn't for Deathly Hallows I 
might have done two ;o)

Thanks lots and lots again for everyone's help and input on this.

Cheers,

Andrew

_______________________________________________
Triumph Sprint ST/RS mailing list
Send list posts to ST@xxxxxxxxxxxxxx
Change your list options at www.Triumphnet.com