thought id ask on here as they have no idea on the vr6 owners club. when cold its ok when warm it idles anywhere between 500-650rpm hunting every now andthen. ive now run out of ideas -

i have replaced the following in my years of ownership -

new lambda sensor
new HT leads
new dizzy
tried several idle control valves
tried another throttle body
tried another inlet manifold
sprayed engine to too see if theres any air leaks
replaced all vaccum hoses at back where idle valve is
new temperature senders
cleaned the MAF
had it on VAG COM and there are no fault codes
new 4 bar fuel pressure regulator

any ideas would be great, i havent touched the injectors or the ecu side of things.

 

Sounds like you've done all the usual

Early VR6s with idle valve always seem to idle shit, mine in my mk2 is the later engine with stepper motor, no probs with the idle.

Only thing I can think of is a bit of a 'bodge' but.. If car does not have AC , there's a spare wire on the ECU that (when AC fitted) goes to ground with AC on , and raises the idle speed, if you ground this spare wire on the ECU it raises the idle speed. Seem to remember it being a blue wire, will see if I can find out which pin.

 

yep early obd1! i know the odb2 everyone says they have a better idle!

yep it doesnt have AC!

 

http://www.a2resource.com/electrical...nicvr6aba.html

Pin outs on here.

Looks like it's pin 39 blue/red.

Other things to check are -

Check voltage on fuse 15 with key on, if ignition switch is playing up, you get less voltage on fuse 15 and this feeds ECU.

Also check relay '30' if it's hot when running replace it.
Also yours will have a '109' relay which is for ECU,check that too.

 

top man that was my only other thought was electrical related! so if relay 30 and 109 are hot ill replace them.

any ideas what voltage fuse 15 will kick out?

when cold it runs fine, just when warm!

 

With it running,warmed up check battery voltage across battery - Say it's 14v

Then check fuse 15, should be same voltage. Had ignition switch fail on my mk3 last year, only had 10 volts at fuse 15 when warm.

 

cool so when your ignition switch went the bad idle started i take it?

 

Mine (mk3 is an 8v GTI) had overfuelling issues and during sorting that out I found the ECU had low voltage as above.

Pretty common fault on mk3 Golfs.

 

Coilpack? I know my mate had issues with his coil pack on his VR6

 

as above 1st post car doesnt have a cooil pack bud.