1994 corrado VR6 wiring question

[almeidk 10]

hey guys

 

so Ive been doing alot of research because my car has a slightly rough idle.

which i quickly learned was probably my isv.

when i checked it didnt vibrate so i checked to the voltage across the terminals.

it reads only 2.5 volts not the 12v its supposed to.

from there i knew there was probably a damaged wire.

took the plastic engine covers off and the wires looked good. (they had a couple sharp bends and one or two twists so i replaced those parts of the wire)

So now im very confused because the wires to the isv look good as far as i could trace them (underneath the windshield washer fluid bottle).

I have the wiring diagram for the vr6 corrado but im not expert on reading wiring diagrams.

From what i can see the isv has no fuse and it has two wires that go directly to the ecm (page 11 and page 12 of wiring diagram).

(it seems wierd that the isv wouldnt have a fuse on its circuit.)

Corrado94.pdf

 

Am i reading the diagram correctly?

If not where does the isv connect to the fusebox ( which plug and pin position ( on the 16valve i kno its plug g2 pin 4 but on the vr6??)

And can anyone think of why the isv would be receiving 2.5 volts instead of 12 volts?

Has anyone had/fixed this problem?

Any trouble shooting suggestions?

 

I appreciate any help

thanks

kevin

[Roger Chatfield 0]

Out of interest, what's an isv? I too have a lumpy idle, I thought it was just because I have aftermarket cams.

 

Rog.

[GlosterOx 0]

Idle Stabilisation Valve, looks like this: http://www.ebay.co.uk/itm/231078964470?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

 

Ian.

[Roger Chatfield 0]

Ahhh, so is it the Idle Air Control valve on the wiring diagram.. IAC valve.?

 

Rog.

[almeidk 10]

yea its called the idle air control valve on the diagram..

I just cant find out whether or not it goes to the fuse box?...

if you have a rough idle it could be many different things.

 

check out this diagnostic flow chart.

[ATTACH=CONFIG]76271[/ATTACH]

 

to check for vaccuum leaks look for damaged hoses, if they look good, while the cars running use carb cleaner and spray any vaccuum joints and listen for any changes to rpm, be very careful of the exhaust manifold

check to see if your isv vibrates( its under the plastic engine cover at the rear of the engine)..

if it vibrates its working( whether its in spec or not youll have to check)..

its worth cleaning it (pull it off by disconnecting the rubber hoses and the gray electric plug, clean it with carb cleaner a couple times until it looks good, you should also check to see if the isv is receiving 12volts(with the key in the on position but car off) check to see if the gray isv plug is getting the 12volts, while its off you might as well check the resistance across the terminals ( dont have the bentley manual so im not 100% sure what it should be hopefully someone will post it)

let dry and reinstall

 

if that doesnt solve your problem its most likely your maf ( clean that also but be very careful because most maf's are very expensive)

 

if not that it could be a number of other things

 

this forum is full of very good information

use google search instead of the forum search and you can find pretty much anything your looking for

 

i highly suggest gettin your hands on vag com

and the bentley manual( looks like im getting one too cause im at the point where i need one, unless someone helps me out :) )