Idle issue

[russ-vdub]

Hello everyone, sorry if this has been discussed before but couldnt seem to find a thread similar.

I have a piper high lift cam which would immeadiately mean a lumpy idle but thats not the problem im having. When driving, say in slow traffic, the car sits nicely at the revs you hold it at, but when i put the clutch down to change gear, the revs drop off, to around 500rpm shaking the cabin, and then pick back up to normal idle (900ish rpm). I have a feeling it maybe the automatic choke but im not sure. another thing to note is i have a slight hole in one of the downpipes which can't be repaired as it is leaking on the flexiable/meshy part of the pipe.

any ideas to solve this would be great, apart from gettin a new downpipe which cant wait to change     :embarassed:

cheers

Russ

[russ-vdub]

no ideas ?

[8vRicey]

What fuel do you use ?
I used to get this occasionally before switching to Super Unleaded.

Either that or ISV ?

[takethefifth]

Hi Russ, 

It sounds like a normal idling issue so i'm suprised you haven't found anything to help.  Do a search for 'Idle Problems' or 'Hunting Idle' and check all the bits covered by those. You will be looking at vacuum leaks, sensors, ISV, microswitch connections etc.

Also what engine is it?

Ta,

John.

[russ-vdub]

cheers for that.

its a pb engine and i generally have to switch from super to normal unleaded all the time cos my crappy sainsburys always runs outa super and thats the only place that does relatively good stuff near me.

strange about this i had a major crack in my mid box exhaust, welded that up and it stopped..but the problem has come back again so i have a feeling all the bits and pieces are ok but its something to do with back pressure maybe. since that can was welded it has put more pressure of the small hole on the downpipe, makin it gradually bigger, could this be the problem?

bit of a noob the hole intake, vaccum hoses etc so i'll have a read about the isv as i have no clue what that is or does, cheers again

[russ-vdub]

takethefifth, nice one on the hunting idle, never heard of that term before but after searching that i think i just need to sort everything out. exhaust, isv, hoses etc and then give it a rubjonny tune. if that dnt sort it i'll jst put up with it lol

[Conker]

I made a big (but not exhaustive) list of "possibilities" a while back, although it was for a 16v, so not sure how many are relevant to 8v'ers:

http://www.golfgtiforum.co.uk/index.php?topic=71501.msg569972#msg569972

[russ-vdub]

cheers conker, can cross a few things off now..but i found the problem, the air flow screww had been wound right out but iafter a few turns back it stopped the hunting... thing is i lost some power as the engine now is gettin less air, mean less few etc etc... this avoidable by any means?

[Conker]

cheers conker, can cross a few things off now..but i found the problem, the air flow screww had been wound right out but iafter a few turns back it stopped the hunting... thing is i lost some power as the engine now is gettin less air, mean less few etc etc... this avoidable by any means?

I doubt you would have "lost" power? If anything you should gain power by fixing an air leak (if it was a leak). Perhaps your CO2 setting now needs balancing??

[rubjonny]

chec k the idle switch is clicking and the wiring to it hasn't snapped, make sure the throttle cable isn't too tight either, throttle should snap up to the stop firmly.  Once thats sorted replace the vacuum lines on the throttle body, VW will sell you 5m for £6, well worth it especially on a digi!  Also check the rubber bung the PCV valve sits in, the big black round thing.  Pull the valve out and then the seal by squeezing it and pulling out of the lip carefully, inspect it closely especially round the groove.

Once thats sorted and you're 100% sure you have no vac leaks reset the ignition timing then the idle & co as per my FAQ