'elp.. failed MOT due to high idle prob

[Overseer]

ok so the high idle prob i mentioned a few times before has cost me (well retest is free...) an MOT..


because it idles so high it fails the emissions..

and it also cant hit the "low" box on another test..


my idle is typical 1200 and if i rev it up it can stick around 1800


now the problem is.. whats causing this?

my dads mate tried cleaning up the idle stabilisation value but its pretty much a sealed unit

i just priced up an idle stabilisation valve in my local stealership and it came out? at 275 quid (ouch)


but have been told could mean throttle body needs cleaning, or that theres an air leak somewhere..

guess it really needs to go on a reader

[Overseer]

my local VWspecialist is shut today.. booooo...

but i went to one a lil further away  to AM Cars illminster (they have a lot of cool looking hi performance quattro's there)..

he put it on a fault reader and it came up clean..


its a really easy job to replace it.. so cant be arsed paying a garage to do if its def the idle valve

i have 1 week since i get that time till free retest runs out, and that day coincides with my mot running out too..

[Dizzie]

could be a leak vacume hose. I always thought if the ISV was shot it would idle eratically up and down. cant' say I've ever had one go wrong... yet.

[Overseer]

one of the parts guys at the stealership suggested that.. he said one way to find leaks was to run the car and spray a mist of wd40, and that it'd make the car splutter if there were some.

it has gone through phases of hunting up n down.. but not very much.. its more likely to not come back down to idle.

i heard theres a plunger in the ISV so maybe thats stuck or broken?


will look for leaks with the old boy tomorrow

[Overseer]

been lookin around some more... it doesnt seem to hunt or be erratic at idle like some people describe... so hope its not really the ISV.. i'm praying for a cheapish answer

gonna check for this tomorrow as well as for leaks..


http://www.golfgtiforum.co.uk/index.php?topic=10606.0

( thread is called "high idle problems caused by throttle switches! " )

[Overseer]

ok.. so far this morning (off to halfords to buy some carb cleaner...)


ISV checked while car running.. it buzzes.

ISV removed and car started...

rev's are around 800, its a bit lumpy. it falls back to idle faster than with the ISV turned on. (kinda like how i'd expect car to run)

from what i've read i think that might rule it out of being a problem..



one question....

theres a piece of pipe coming out from under where the ISV plugs into the manifold.. its about 3/4 inches long and has a screw in the end of it. removing this pipe (only tried with ISV present) makes the rev's dip a little.

whats it for? should it be left open? or should the pipe actually plug into something ?

[Gambit]

for the retest just take it thru with the isv disconnected.

im not sure what governs the ISV on mk3's so cant really help u out with whats causin it to idle high

[Overseer]

yeah true.. i want it fixed properly now.. if i'd known what i know now at the time i would have disconnected it there and then.


i've booked it into a local vw specialist that i havent used before ( ** touch wood ** they're good.. they're in wood street after all.. lol)

i usually use http://www.carshoptaunton.co.uk ... ?they were shut due to "family bereavement" on sat when i tried to see them.. and they aren't answering the phone today.. so its off to http://www.performancedriven.co.uk instead


a couple things are still bugging me...


1.. the pipe that comes out of the manifold under where the ISV goes in. why is it apparently sealed off.. (it has a screw in the end and that screw is held in place with a zip tie).

2.. why the throttle butterfly has a hole in it.. btw.. noticed when i had the throttle body off a shard of metal was actually coming off around that hole. on the inner side.
makes me think its been modded.. grr..

3.. theres a pipe that runs across the back behind where the throttle body is. it has "motor" written on it and has direction arrows.. a connection that comes off this is partly split and has a f**kin wood screw stuffed into it. grr.. 


think i need to get me a bentley manual damn quick. haynes sucks ass for valvers.


oh and to make things worse i'm running with 3 screws on the throttle body coz i bloody dropped one and its lodged somewhere... and vw cant get me another till tomorrow.. grr..



since i took the throttle body off and cleaned it (and lost damn screw) it seems to stick at a higher idle, and appears to hunt a little now.. :/

[Overseer]

have dropped it off.. the guy seems pretty good now i've seen him the flesh... am expecting him to call in a few hours

[Overseer]

ok got it back.. (for today..) its goin back tomorrow...

the ISV is fine.. no probs with that at all.

lets take a trip back to my 'bugging things'?


number 1..

next to where the lil bit of pipe was capped off is a cover.. under that cover is where the pipes meant to go! #1 solved.


number 3..

the thing i described is something to with the word "servo".. the guy said he used to be an MOT tester and would have failed it having seen that alone. they've ordered me a new one for tomorrow.

they said its leaking air.


the car already idles a little lower and behaves a lil diff.. will see better when its cold i think.

they said they did have it running perfectly at one point, then it started doing it again.

they're also gonna replace some other hoses.. they are gonna charged me only 1/2 hr labour for todays bits..




the only worry is there was only 1 of that part left in vw uk..?