IDLE PROBLEMS - 8V Mk2 GTI 89 model

[AUTOYPISTA]

Hi. I am new to this site as I only bought my Golf two days ago. The most major problem is the tickover / idle. When cold she will start fine. Then, when warm she hovers at around 400 - rises up to 1600 - then back to 400!! I put her in for an MOT today but she failed - due to the CO mix. This is caused by the fluctuating revs. She is an 89 Mark 2 GTI. I have new plugs, etc, and I am now at my wits end. Once driving she is fine!! Any help would be appreciated. Thanks.

[mk1]

First have a good look at all the vacuum hoses, small pipes and breathers. Change the oil and the filter, then after a good run adjust the mixture screw (allen headed screw in the air flow sensor) out untill it idles smooth. Back to the MOT garage for a re test (free next day if it failed on free re test items,emissions is one of them) and if the tester is half decent he will set the idle mixture for you. Hope this helps, Steve.

[AUTOYPISTA]

Thanks for the advice but I cannot seem to locate the allen key hole?? Sorry - stupid question I know but I am new to Golfs and do not have a Haynes yet. I checked all the pipes and they were all fine. This is so frustrating. Started her this morning and she ticked over for about an hour on the drive ok. Then I drove her round the block and she is back to jumping up and down.

[mk1]

The allen key hole is in the air flow sensor, near the square black top bit. It is down a hole (10mm dia. ish) may be coverd with a blue plastic disc that you pick out. Hope this helps, Steve.

[richandhazel]

Hi, got your message, sorry for the delay in responding to this one, the forum is getting so much busier now it takes time to work through all the new posts.

That problem sounds like your ISV (Idle stabilization valve), assuming you have that fuel system fitted. It probably simply needs removing and cleaning in some carb cleaner.
Have a look at the following links and see what you make of them. Make sure you do look at the very last link to do with the Audi..........it describes your problem precisely

Have a look here to identify which fuel system you have fitted, I suspect you have the Digifant:-

http://homepage.ntlworld.com/richandhazel1/Fuel/Fuel_system.htm

If you do identify it as the Digfant, here is a fault finding guide:-

http://homepage.ntlworld.com/richandhazel1/DigifantOBD/Troubleshooting/ESIS.htm

A common problem is, as I said above, the ISV. Have a look here for more info on that:-

http://homepage.ntlworld.com/richandhazel1/ISV/index.htm

Also have a look here, its an Audi page but the same applies and describes your problem precisely:-

http://20v.org/engprob.htm#isv

 

[AUTOYPISTA]

Thank you to everyone who helped with this problem...and to the Site God...who sorted it for me with his in depth post and links..thanks so much:)

[richandhazel]

Just hope it helps........my Audi 20V gearbox blew to pieces to day.  :'( Gutted.  :'(

[richandhazel]

Going to get underneath it today and see if I can work out what has happened. Certainly sounds terminal.  

[richandhazel]

Good news, it wasn't the gearbox afterall.  
It sheared all the bolts that connect the driveshaft to the gearbox  
Just need to get a new set of bolts and rebuild the CV joint. Bit cheaper than a new gearbox.