GTI 16v Cold idle problem.. Testing the ISV and wiring.. HELP!

[JRW91]

Okay, plugged the multimeter in. Got a reading of around 7 but the car was erratically idling. Would it be a gunked up connection restricting the power?

[itavaltalainen]

probably ok, if you're measuring dc.
the ecu pulses the output, to look at the waveform you'd need an oscilloscope.

have you checked the temp sensor already?
it's in a different location on the abf (since the manifold goes round the front) but the procedure is the same there.
you can measure the temp sender in situ at first (cold in the morning when it shows just about 50-60 and then when it shows 90).

http://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=719242

poor cold idle could be due to that as well....

[Jasikasisback]

where is this thing located???i'd love a pic from the AAM engine as mine is the same. tried to find it on the net, but no luck.

[JRW91]

Cool, I will get testing that as soon as i get in from work

Only question is though.. again i'm still new to all of this, and cant find the answer on here, where on earth is the temp sensor on my 1997 mk3 golf gti 16v?

Thanks for all the help

[itavaltalainen]

where is this thing located???i'd love a pic from the AAM engine as mine is the same. tried to find it on the net, but no luck.

look at the pdf i've linked... all in there (photos are actually from an aam but its the same for abs, 2e, ady, agg)

on abf I think it lives on the side of the cylinder head. would need to check but dont have time today, need to party

[Jasikasisback]

sorry i meant the ISV.

[JRW91]

Okay tested that! all seems to be fine with the temp sensor!

Found a broken vacuum pipe from the little nipple just below the ISV.. fixed that and now the isv seems to come alive when the ignition is switched to on.

Now it will not start at all though!!!!!
It is making all kinds of buzzing and vibrating noises, seems to be coming from one of the pipes running to the fuel rail?
I can no longer connect to the engine with my obd2 reader either!!

Major frustration!!!
Any help would be massively appreciated as i need this car to get to work.. now that it wont start im buggered!!

[JRW91]

This is the pipe in question..

[Dogbot]

That's the fuel return pipe... Doubt that's where the buzzing is  from unless your injectors are randomly firing.. Which I doubt on the basis of your posts

Also the isv is powered by 5v feed controlled trigered by the ecu, if you've rammed 12v up its backside I doubt it's done it much good.... Although the are just a motorised stepper to produce an air gap that opens an closes, so can't see it mullering it to much, fuse 15 is the one for isv (engine electrics) I would have checked this but if you saying you have buzzing and your sure its isv then that's not the problem... They are quiet simplistic really

[JRW91]

The fuel pipe seems to have just sorted itself out on its own.. and the car will now start again.. all be it with a bit of throttle applied to stop it from stalling.

I have removed the ISV again and have left it since last night full of WD40 and capped off at both ends, hopefully this will really clean the bugger out.. i will dry it and reattach it tonight to see if this has helped at all.

Did have 7v running to the ISV so i don't think it will be the fuse, although i will check it just in case. 

Thanks for all the help guys.. will keep you all informed of any changes, in the mean time any more helpful ideas would be appreciated!