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Adjusting idle speed Mk2 GT 1.8 Auto Pierburg

Posted: Mon Sep 28, 2009 8:42 pm
by RevDarkman
My rocco idles at 2000rpm when warm, it's actually a little less when cold!

Where on earth is the idle speed adjustment on this carb?

When looking at the carb from the front of the engine, theres a face on round thing on the left side of the carb, I suspect this has something to do with it as I can push the piston in on this and slow down the idle speed - am I in the right area?

Ta v much!

Re: Adjusting idle speed Mk2 GT 1.8 Auto Pierburg

Posted: Mon Sep 28, 2009 10:25 pm
by dozzum
directly behind the piston is a 13mil adjuster for the idle speed,
enjoy getting back there and turning it. and the CO mix is under the airbox in the top at the back.
If i were you though id be inclined to check all your vacume hoses before you start messing with the pierburg, they are very tempermental.

Re: Adjusting idle speed Mk2 GT 1.8 Auto Pierburg

Posted: Mon Sep 28, 2009 10:31 pm
by RevDarkman
heh I'll have a crack at the weekend again on this.....

Did check the vacuum hoses (oh so many) and they appear to be ok. I've just bid on a haynes manual on ebay, so should have that for the weekend for reference as well.... I'm beginning to hate hovering on the brake so much.... on a flat road it will actually change gear on tickover!

Re: Adjusting idle speed Mk2 GT 1.8 Auto Pierburg

Posted: Thu Oct 22, 2009 7:49 pm
by RevDarkman
Hmm I've been lost on this, everythign looks in the right place when I compare to my Haynes manual. The only other thought I've had - Could my autochoke be connected the wrong way round? As the hotter it gets, the higher the tickover!

Re: Adjusting idle speed Mk2 GT 1.8 Auto Pierburg

Posted: Thu Oct 22, 2009 8:41 pm
by dozzum
The choke might not be fully opening when warm. Take the airbox off and watch what happens as it warms up. You should see it start off closed and then open as it warms up. Here are some pages i used when trying to diagnose my pierburgs problems that turned out to be caused by something else. http://members.fortunecity.co.uk/baden/2e2.htm
http://www.clubgti.com/FORUM/showthread.php?t=36156
http://www.clubgti.com/forum/showthread.php?t=144497

Re: Adjusting idle speed Mk2 GT 1.8 Auto Pierburg

Posted: Thu Oct 22, 2009 8:54 pm
by RevDarkman
nice tips!

Thanks for that, I'll have a look at the weekend

Re: Adjusting idle speed Mk2 GT 1.8 Auto Pierburg

Posted: Thu Oct 22, 2009 9:53 pm
by dozzum
Check all ur vac hoses go to the right places. these are helpful.
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Re: Adjusting idle speed Mk2 GT 1.8 Auto Pierburg

Posted: Fri Oct 23, 2009 7:53 am
by Nate
also make sure the throttle cable is actually letting it close all the way to the stop. if the cable is a bit tight it'll bring the idle speed up