Re: [ST] Check Engine Light on

[Rusty Ford <rford@xxxxxxxxxxxxxx>]

My 01 ST with dealer tune for S&S pipe runs great but will stall when 
declutched in a higher gear. Could it be that the POS sensor / setting 
is at fault?

 Frederic NIZERY wrote:

>Marc,
>
>Yes it is. ISO 9141.
>You can as part of the standard software OBDII port (PID).
>I think I noted at  home the bit map of the supported PID on
>my 02 ST.
>
>I use windows at home (linux at work) and I only tried windows
>software for that matter.
>http://scantool.net/?mode=displaySoftware&software_id=39&category=ScanTool.net
>I use also my PDA w/
>http://www.qcontinuum.org/obdgauge/
>
>Note that I don't have the bit map for the pre 02 engine. Probably the same
>except the O2 sensor which is not present on this model.
>I can read most of the sensor data and the fault codes. I can reset the 
>MIL too.
>
>The problem that you could face is adjusting the CO rate as it's 
>proprietary PID's.
>The throttle position sensor could also be a problem as the it's the 
>absolute throttle pos
>that can be read and not the relative pos. The absolute pos is related 
>to the potentiometer
>voltage reading, and the relative one is related to the corrected 
>position as used by the ECU.
>To make it short, the relative position should be 0 or very close to 
>when the throttle body
>butterflies are closed.
>
>But their is a trick to bypass that problem that works most of the case 
>(worked for me).
>SOmething I learned reading carrefully the tuneboy online help. Fasten 
>your seat belt:
>When starting, the ECU reads the relative throttle position RelPos.  
>RelPos is calculated
>by:
>AbsPos - CorrectionFactor = RelPos
>
>If the reading is negative i.e. RelPos < 0, then the ECU recalculates 
>the CorrectionFactor
>and keeps it in flash.
>
>The dealer procedure and the tuneboy procedure is to modify the 
>CorrectionFactor (they can do it w/
>proprietary PID) turn on the key and then the ECU will compute a new 
>CorrectionFactor to have RelPos = 0.
>
>TuneBoy event mention that they post-adjust the CorrectionFactor in a 
>tiny extend. I think to avoid the
>stalling problem when the throttle close up rapidely w/o any charge (in 
>neutral or clutched out).
>
>But you can reach the same point by setting AbsPos. Setting AbsPos means 
>moving the throttle position sensor
>(it is on the left of the throttle body on the 02 engine) in such a way 
>that AbsPos becomes lower than CorrectionFactor.
>But it's a blind manipulation as you can't read CorrectionFactor nor 
>RelPos w/ the stadard PID's.
>Then the next time you switch the key on the ECU will adjust itself.
>
>Honestly I don't remind for sure if it's clockwise or counterclockwise. 
>I could probably have a look at mine as I put
> the sensor at the max possible position. But I have to remove the tank 
>probably which is not so easy.
>Normally, giving the direction in which the butterflies rotate you can 
>determine that yourself.
>
>Then how I know it worked? Because w/ an O2 sensor, when the ECU reads 
>RelPos = 0, it will use the O2 sensor voltage
>to regulate the mixture. Then you can see it going up and down arround 
>0.5 volts (0.450V actually). And w/ scantool, the last
>indication of the first page (I don't know which PID it's related to) 
>it's showing if it's driving, idling closed loop or idling
>open loop.
>
>The reason why I had to do that is because my dealer mechanic  wasn't 
>able to fix a stalling problem properly and modified
>the pos sensor to enrich the mixture artificially (he didn't say it 
>though). I just saw the scratches on the sensor screws.
>Result: no more O2 sensor regulation and a consumption going hight and 
>higher when commuting.
>
>Hey, Hey. Are you asleep?
>
>Fred ST 02 BRG
>
>
>
>
>
>
> 
>
>_______________________________________________
>Triumph Sprint ST/RS mailing list
>Send list posts to ST@xxxxxxxxxxxxxx
>Change your list options at www.Triumphnet.com
>
>
>
>  
>


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