MK2 GT2 over revving

[willgt290]

1990 Scirocco GT2:

When I start the car it revs up to around 1600 which is about normal for a cold engine, however when I drive off and then come to a stop again the revving has increased to 2000 plus. As I am currently only doing short journeys the engine doesn't seem to calm down and stays loud whilst idling fast.

I am concerned that it may be more serious than a mere timing adjustment, but am not sure what it could be.

[Crasher]

It will normally be one of two problems. If the carb itself is OK then I would suspect it is either the wax operated thermostat on the front of the carb and if it is alloy bodied they are the unreliable type, the later black plastic type are better. A common issue on the Scirocco 2 and Golf 1 Cabrio using the 1.8 carb engine (EX on the Scirocco and Cabrio, GU in the Golf) that the Golf 2 does not suffer from is that the clutch cable passes very closely to the wiring for a device called a Thermo Time Valve which is on the side of the carb and the wiring is very vulnerable to damage. To me it sounds like your problem is a lazy wax stat causing the initial high idle (1600 is too high) and then the 2K idle being the result of the TTV not getting power. One way to tell is to let it idle long enough for the idle to come down, if it suddenly drops that is a common indication of the TTV not having power.

http://i222.photobucket.com/albums/dd20/Crasher1964/2E3TTV.jpg

[willgt290]

That sounds right. My idle is unreliable at the moment, although it was never caused the car to stall it does suddenly rise/drop seemingly at will.
Is it pretty cheap to put this right?

[Crasher]

Have a look and see if the wiring to the TTV is damaged.