High idle 16v

[Alexg40]

Merry Christmas!!

My 89 16v today started idling at about 1100rpm.  Any ideas??

[Gambit]

idle for a 16v is 950/1050rpm when upto to operating temp, just give the idle screw a small tweak clockwise and it will lower it

it will idle higher in cold mornings (cold starts) but this will eventually drop as the engine gets upto temp

[Alexg40]

Yes well, yesterday it was doing it after a 25 mile run down the motorway, so it was pretty warm!! Today it hasn't done it at all. I'm a bit confused by all this 16v malarky, I'm a G man meself! Has anyone else had this prob??

[golfvr6]

Check for air leaks around the throttle body and inlet, also check ISV.

[Alexg40]

By ISV I assume you mean Idle Stabilisation valve?!  How and what do I check??

[Alexg40]

Help me please!!  I know bob all about these 16v thingies!!  

[Jon16]

Does the idle stay fairly constant once it's at 1100 rpm? If so it probably justs needs the idle screw turning down slightly to about 1000rpm - its on the throttle body. People turn it up slightly in winter when you have a higher load (heater, lights, rear de-mister etc) to stop the car stalling at lights, when parking etc. The screws tend to be a bit loose and can adjust themselves slightly (some people even put a speck of pain on them to stop unwanted movement). However, if the idle is erratic then it is probably the (expensive) idle stabilisation valve.

[Alexg40]

It's not like it has gone up and stayed up. This morning it did it, but tinght it was back at around 900rpm.

[Gambit]

just disconnect the ISV and try running it

ive been running mine for about 6mths or so without it

[Alexg40]

That's just it!!!  I don't know what it is or where it is OR how to diconnect it!!