Discussion
My S1 appears to have a seized idle adjustment screw. It has been idling fast 1500 since the last service and so I dug out the bible and found the idle adjustment. It doesn't turn under reasonable pressure 
and the last thing I want to do is break it off as it is not the worst problem I have had, but if anyone has come across this before and solved it I would be interested to know. (this might be specific to the 2.8, not sure if the 2.9 has the same adjustment mechanism)
Dave
and the last thing I want to do is break it off as it is not the worst problem I have had, but if anyone has come across this before and solved it I would be interested to know. (this might be specific to the 2.8, not sure if the 2.9 has the same adjustment mechanism) Dave
Teh idle speed is controlled by the ECU on the 2.9.
There is however a grubber screw to adjust the idle on the side of the throttle body which effectively prevents the butterflies from closing fully and therefor increasing idle speed.
If it this grubber screw you refer to then they are usually locked into position by a small locking nut. This will have to be undone to allow any adjustment of the screw.
If you have undone this and it still will not turn then I would look at repetitve use of WD40 or penetrating oil over the next couple of days.
My question would be to the garage though to ask whether they have adjusted the idle speed and if so how ? If they used this screw then presumably it moved for them and what have they done to change this. If they adjusted via the ECU then you may need them to readjust it.
I have mine set so that the butterflies both are fully closed which then lets control idle speed and mixture via the Aux Air Valve. As the Throttle Pot is telling it the throttle is now fully closed.
Idle speed can be adjusted by changing the mixture at the air flow meters aswell.
To come to a point ! I would check with the garage as to exactly what work they carried out that may have effected the idle speed from the above list (not forgetting that the timing can cause variation aswell) Once you know what work was done then you can eliminate other possibilities.
Cheers
Mark
There is however a grubber screw to adjust the idle on the side of the throttle body which effectively prevents the butterflies from closing fully and therefor increasing idle speed.
If it this grubber screw you refer to then they are usually locked into position by a small locking nut. This will have to be undone to allow any adjustment of the screw.
If you have undone this and it still will not turn then I would look at repetitve use of WD40 or penetrating oil over the next couple of days.
My question would be to the garage though to ask whether they have adjusted the idle speed and if so how ? If they used this screw then presumably it moved for them and what have they done to change this. If they adjusted via the ECU then you may need them to readjust it.
I have mine set so that the butterflies both are fully closed which then lets control idle speed and mixture via the Aux Air Valve. As the Throttle Pot is telling it the throttle is now fully closed.
Idle speed can be adjusted by changing the mixture at the air flow meters aswell.
To come to a point ! I would check with the garage as to exactly what work they carried out that may have effected the idle speed from the above list (not forgetting that the timing can cause variation aswell) Once you know what work was done then you can eliminate other possibilities.
Cheers
Mark
Thanks Mark
I'll check the bible again to make sure I haven't missed anything obvious. The screw itself looks pretty rusted which is why I think it is seized. Failing WD40, I'll give the garage a ring although I suspect they have tuned it up nicely but were unable to adjust the idle because apart from this it is running really well. Good day today - went out at lunchtime into the Berkshire countryside with the top off. Best day so far this year I think
Dave
I'll check the bible again to make sure I haven't missed anything obvious. The screw itself looks pretty rusted which is why I think it is seized. Failing WD40, I'll give the garage a ring although I suspect they have tuned it up nicely but were unable to adjust the idle because apart from this it is running really well. Good day today - went out at lunchtime into the Berkshire countryside with the top off. Best day so far this year I think
Dave
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