Revs stay a bit High

[WonkyGibbon]

Just a quick Q - nothing serious. I got my S3 only a couple of weeks ago so I'm still learning my way around it. One thing I notice is that after I pull up at a set of lights or stop for some reason - the car keeps the revs at about 2000 all by itself (no right foot) for 3 or 4 seconds before dropping to 1300 (ish). Is this normal ?

[roy_allen]

Your pedal could be sticking a bit, mine does this too. I`m not sure if this is the same on all S's but there is no spring on my accelerator pedal to return it to rest. On my setup, the pedal is pulled back up by the throttle mech springs which are only just strong enough to do this. So if I take my foot off the pedal fairly quickly there is no problem, but if I take it off very slowly then the throttle will not quite return. I just blip the pedal and then it comes back.

I`ll have to get round to sorting this out somehow!

Roy.

[WonkyGibbon]

Oh right - I'll give that a whirl later, thanx

[Colin BlueS2]

Yes I have a very similar problem, playing around with it this weekend (at Back Home) it seems to be something to do with the throttle butterflys.

There are two spindles on the throttle body, the first set are connected directed to the throttle mechanism. But the second one (furthest from the air intake) is controlled by an actuator on the first spindle. I've noticed that if I blib the throttle then the revs just stay up at 1300-2000. If I physically push the second spindle back against the stop the revs die down to the normal 900-1000 revs. It's only a matter of 1 or 2 mm of movement but it has the desired effect.

I think either the return spring on the throttle body is tired or there is some dirt in the mechanism stopping it return properly. Going to try and clean it tonight so will let you know how I get on.

Colin

[Colin BlueS2]

Well I finally found the time to get under the bonnet, I degreased the area around the spindles and springs because they was covered in grease and cr*p. Then I applied some light lubrication to the spindles and pivot points. Did this several times and then worked the mechanism to make sure the oil was getting into all the right places I warmed it up revved it a few times and it dropped back to 900 rpm every time. Haven't had a chance to take her on a run yet but so far so good.

Not sure if the light oil I used will be thick enough to stay in place but if not then I'll apply something a bit thicker but I didn't want to gunge the whole thing up again.

Colin

[roy_allen]

What type of oil did you use to lubricate the mechanism??? I dont want to alarm you (and I may be wrong about this), but the parts of the mechanism that the springs wrap around are plastic (they are on mine anyway), and I think that over time some types of oil can begin to dissolve some types of plastic (plastic after all is ultimately made from oil). I am fairly sure that the plastic used will be of a type to prevent this from happening and again I could be wrong about the whole thing, but it may be worth looking at. Anyone else any thoughts on this?

Roy.

[Colin BlueS2]

I used a silicone based lubricant that is safe on plastic and metal. But it was covered in copperease before I cleaned it up!

I couldn't see any plastic bits apart from the connecting arm.

Thanks anyway

Colin

[minghis]

It sounds as if you've fixed it, but on mine the underbonnet insulation pad droops down and the throttle linkage has been fouling it. This could have been a contributing factor.....

Minghis.