Problems turning engine off

[T_J_G]

Right,

when i go to turn off my engine it revs down, then bangs a bit then it'll rev back up to idle then cutout.

doesn't do this all the time although it is very annoying.

Is this a common problem, how can it be fixed?

Tim

[rubjonny]

What car? Can be caused by a few things:
1. Excessive carbon build up in the bores, can be solved by putting water/carb cleaner into the inlet whilst the engine is running
2. Overheating, make sure the fan works and the engine stays around 1/2 on the gauge
3. If its a carb, a faulty idle overrun valve.  Make sure it gets 12v when the ignition is on and that it clicks when you turn the key.  See:
http://www.golfgtiforum.co.uk/index.php?topic=33259.0

[T_J_G]

The car is a 1.8 carb Driver.

i will try number one.

number 2) the engine never goes above 1/2 temperature and the fan does cut in.

3) i'll check thatone out thanks! But wouldn't that affect the car on idling aswell..the car is fine otherwise..

[rubjonny]

Nope it wont, mine was the same untill I swapped this part out.  Once I did it was instant off on the key every time
I also had tons of carbon build up as it had been running way too rich for ages due to the o'ring failing in the inlet manifold as they do.  Half a tin of carb cleaner sprayed down the carb choke flap and the carbon was all over the drive rather than in my engine 

[T_J_G]

I may go buy some carb cleaner now. What part do your pour it down, will i bugger anything up if i dont pour it in the wrong place.

Tim

[Haribo!]

easiest way is to take that plug off the top of your airbox and spray right into the carb, youll have to blip the throttle to teep it running or it will cut out, itll sound very unhealthy but it loves it really, try and do abit at a time, i found it easer that way, doesnt cut out as much

[rubjonny]

Just take the airbox off completly, and spray it into the flap in the top.  Prob better to do it when the car has warmed up a bit
You can give the carb a general clean while you're there too

[T_J_G]

Got the stuff...It's just had a 20 min round trip so it's fairly hot shall i leave it for some time?

It's Car Plan Carb + Throttle body cleaner only one they had.

[rubjonny]

That'll do, just get it in there
I cleaned out my airbox while I was there too, lots of oil in it.

[T_J_G]

off to do it now, will inform of results