mk2 16v idle problem

[Winso]

Spoke to a bloke on the phone today who I'm looking to hopefully buy a mk2 16v off soon. Not seen the car yet, ran through some details and sounds in good shape apart from and issue with the cold idle. He says when started it will idle a bit rough and splutter a bit, then stall when you try to pull off. However if you sit with the revs at about 3k for less than a minute, then drive it, it's is fine and doesn't stall. Said he has had a valve of some sort changed (didnt know what it was called) which he was told would sort it but hasn't. I'm new to mk2s, is this something fairly common or should I stay well clear?

The bloke sounds like he is trying to be honest, but I dont want to go wasting my time and petrol viewing if this is going to be a serious problem.
Car is a 1991 model, if it helps!

[Diamond Hell]

Sounds like he replaced the idle stabilisation valve.

If he's done that then the next port of call would be to clean out the throttle butterfly, using carb cleaner and a 1/2 paint brush.  That should sort it out.  If not, then there's likely to be further issues elsewhere.  Thing is the 16V motor runs K-Jet, which is simple mechanical injection, so it shouldn't be too difficult to diagnose.

[Conker]

When I was looking for a 16v'er, I was put off buying one because it had a poor idle, but now I know more about it, I wouldn't let it put me off in future (so long as the rest of the car was good).

The k-jet system is very simple as Diamond Hell said, in that its all mechanical, but there are many, many possibilities that could contribute to a hunting idle. In other words the diagnosis will take time, not money, e.g. you'll probably be searching for a tiny vac leak, rather than having to buy a new part.

There are loads of posts on poor idle, so you can use the search function for that, but heres a recent one where I compiled a massive (but not exhaustive) list of possible causes (as you can tell, I've sufered with this problem too!!):  http://www.golfgtiforum.co.uk/index.php?topic=71501.msg569972#msg569972


You mention that the guy said that it goes away when the engine is warm?? That suggests something a little different to the usual idle problem (which usually occurs no matter what temperature the engine). At a guess I would suggest it could be a faulty temp sender (cheap fix), or the cold start valve not operating properly, or the warm up regulator.

Overall, if you really like the car, I would say its worth a test drive. You can always come back to the forum with more detail on what the engine does exactley.

PS... Remember to ask him not to warm it up before you get there so you can see what happens on a cold start.

PPS... You might know all this stuff already, but check this buying guide out - helped me a lot:  http://www.matey-matey.com/golf_buying_guide.shtml