Erratic Idle

[AlanD]

Not having much joy at the moment, my dash is light up like a Christmas tree. Need new brakes (low pad warning light on) and this morning my nearside dipped beam light has gone faulty (another light)

Anyway, I've noticed this over the last few weeks now and it doesnt do it all the time (was brought to my attention yseterday again). When Im letting the car cool down for 30 odd seconds my idle sometimes is very erratic and revs itself between 700-1100. What would cause it to do this (sensor?) as I think its probably going to be a good idea that it gets replaced and I can add it to my list.

[Teutonic_Tamer]

Not having much joy at the moment, my dash is light up like a Christmas tree. Need new brakes (low pad warning light on) and this morning my nearside dipped beam light has gone faulty (another light)

Do you have vag-com?  Log all the fault codes, and then clear them.  Get some new pads and a bulb - you cheapskate! 

And just to clarify, it IS just the bulb and pad lights, and nowt else? 

Anyway, I've noticed this over the last few weeks now and it doesnt do it all the time (was brought to my attention yseterday again). When Im letting the car cool down for 30 odd seconds my idle sometimes is very erratic and revs itself between 700-1100. What would cause it to do this (sensor?) as I think its probably going to be a good idea that it gets replaced and I can add it to my list.

Might be the MAF.  What air filter are you running?

And maybe it is just down to high current electricals shutting down - such as air con, fans, even closing leccy windows or sunroof.

vag-com measuring blocks are really needed.

Oh, and you do know that just letting it idle for 30 seconds isn't really the best way of 'cooling down' the engine? 

[AlanD]

Yes it is JUST the bulb and pads warning light. Bulb light came on this morning so will stop off at Halfords on the way home to get a new one. Pads are getting done soon, maybe lol (its a long story).

I don't have VAGCOM (another thing to add to my endless list of things I need) but will be at the Brands Hatch meet next week so will get one of the boys to bring it with them and get it scanned then. I am correct in that I need to clear faults, go for a drive and then rescan don't I?

I'll have to check when I get in (look at the receipt) but I'm pretty sure I'm running a Pipercross filter which got added when I put in my Carbon Speed CAI (that was back in March), either way its not the standard one.

To my knowledge taking it easy for the last mile or so and letting the engine run for 30 seconds is the best practise when shutting the engine off? If that is not true please enlighten me.

[T_J_G]

I'll ask Dan to bring his laptop to Brands mate.

[AlanD]

I take it he has VAGCOM and all the leads? I thought you had it? Was just about to ask you on Facebook when I saw your post.

Thanks mate

[Teutonic_Tamer]

Yes it is JUST the bulb and pads warning light. Bulb light came on this morning so will stop off at Halfords on the way home to get a new one. Pads are getting done soon, maybe lol (its a long story).

Xenons or halogens?  And you are still a cheapskate! 

I don't have VAGCOM (another thing to add to my endless list of things I need) but will be at the Brands Hatch meet next week so will get one of the boys to bring it with them and get it scanned then. I am correct in that I need to clear faults, go for a drive and then rescan don't I?

Yeah, just clear all the codes.  You often find some 'legacy' codes hiding (maybe if the stealer done some work and failed to clear them, and also any alarm triggers) - and sometimes these can affect any fresh DTCs.  Once cleared - any 'genuine' faults will soon reappear.  And if your pads are only just catching the wear sensors, it may be another few days or so before the pad light reappears - which is handy to know for when a certain three letter test is due.   

I'll have to check when I get in (look at the receipt) but I'm pretty sure I'm running a Pipercross filter which got added when I put in my Carbon Speed CAI (that was back in March), either way its not the standard one.

IF it is the MAF, will the pipercross really be worth it?  Just get an OEM paper element.  Why do you think F1 engines dont use foam rubbish - they either use a paper element - or fcuk all!

I think I'll have on my epitaph:

"non-paper air filters are for mugs"

To my knowledge taking it easy for the last mile or so and letting the engine run for 30 seconds is the best practise when shutting the engine off? If that is not true please enlighten me.

Yeah, thats fine.  The real nerdy way is to try and keep 'off-boost' for the last mile - so try keeping the revs below about 2.5 k, and only tickle the throttle. 

[AlanD]

Xenons or halogens?  And you are still a cheapskate! 

Halogen, Im currently running the Phillips ones I got from powerbulbs. Im guessing Halfords will sell them, if they dont then there is a car spares place down the road from me which will sell individual ones so will just get one for now and order the Phillips ones online.

IF it is the MAF, will the pipercross really be worth it? 

Probably not, it all came as one package with the CAI so that's why it went in. It doesnt do it offten, maybe once a week, if that, just odd and a bit concerning is all.

[T_J_G]

I take it he has VAGCOM and all the leads? I thought you had it? Was just about to ask you on Facebook when I saw your post.

Thanks mate

I have the lead but needs dans laptop as
I don't have a laptop with windows on it.

[sambo]

Alan have you changed the PCV valve since remapping etc? There prone to failure after power increase and can cause idle issues like you have. Mine was caused by the DV but you have the forge one, i know they require servicing but not sure what needs to be serviced? May be worth a look?

Sam

[Teutonic_Tamer]

Alan have you changed the PCV valve since remapping etc? There prone to failure after power increase and can cause idle issues like you have.

Huh . . . please explain how a remap can affect the PCV?  Or do you mean the DV? 

Mine was caused by the DV but you have the forge one, i know they require servicing but not sure what needs to be serviced? May be worth a look?

If the DV is on its way out, then it would usually be much more bothersome during high levels of boost.  Again, I can't see how a u/s DV can cause erratic idling!