Cold start and cutting out problem again!

[jocarl11]

Hi guys, Back in summer I had an idle problem which all of you with gti's will know is a very very common problem (cutting out at junctions and dipping revs). What i did at the time was cleaned the throttle body arm and made sure the throttle switch was being pressed which it was working fine! I then reset the idle according to the guide on this site,  i searched for any air leaks which i couldn't find so i got some advice on here and checked the temp sensors on the side of the block by switching the wire for the temp gauge to the other 2 sensors and they proved to be working to. I then cleaned the isv and perhaps for a few days (on and off) ran well but then got even worse and now the revs would just keep increasing untill i cut the engine out! I should say at this point i did buy a second hand isv but the problem was as bad if not worse with the replacement.

Eventually i disconnected the red wire next to the coil and as i remember the car ran fine just idling of the idle screw alone for a while but then the high revving came back to haunt me and i found if i disconnected the hose that goes into the main air intake from the isv and blank it off at the hose and main intake sides it worked fine again!
1 month ago the car went back to square 1 ie.. cutting out when revving when its cold and it doesnt start as easy now either as it takes about an average of 10 to 15 seconds to get her goin! Everything under the bonnet is as i left it so this leaves me with the question as to whether the WUR or even cold start valve could be faulty?

Thanks Carl.

[dan7]

Try disconnecting the multiplug on your WUR. Then start it from cold, that sometimes helps.

[jocarl11]

Try disconnecting the multiplug on your WUR. Then start it from cold, that sometimes helps.

Ok thanks ill give that 1 a try!

[jocarl11]

Ok that didn't do anything, I also disconnected the cold start multi plug and it was still the same! Could this mean the wur and cold start are not working? If so it could point towards the thermotime switch? The car is fine when its warm although a bit powerless.

I also checked for voltage at the cold start when the engine was cold (ish) and i got voltage for a second before it went to 0 but i suppose thats because the engine had been run for a while only a couple hours before.

[jocarl11]

Also the thing i dont understand is how the engine revs will increase to full unless i cut it out with the key! It does this when the isv and connecting pipes are all in line but it doesnt matter if the isv is unplugged at its connector or red spade connecter at the coil the revs will always increase unless I take off the isv pipe at the main intake hose side and blank off both the intake hole and the end of the isv pipe, So i have effectivly completly taken out the isv but in doin so has that taken out the wur and cold start valve? because they are both connected to the isv via that hose i've blanked.

Any help would be great before i buy 1 of those new Idle valves for 60 off ebay and waste my money lol.

[gixer1400]

hi about those idle valves on e-bay bought one for my mk2 and it started ok idling at about 1100 but after i drove for a very short time and stopped at a junction the revs went up to 2300 and then down to 900 as if i was blipping the throttle continuously 
made me look lke a boy racer 
ended up sending it back got a replacment which made it a pig to start as if the cold start choke was not engaging but ran fine after 
an odd thing is that the temperature gauge with the old valve takes forever to move off the cold position in fact not moving at all on my 8 miles to work but the new one is very quick moving up within a couple of miles whats that about ?  
do you take a chance with a new one and waste your money mine is in the boot but its not gr8 with the old one as it does drop the revs as if its about to die then picks up again but at least it starts 1st time