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22
Engine & Gearbox / Re: High rpm when cold for 20 minutes,...?
Last post by Keekster64 -
Quote from: philip on
Thank you very much for your very very helpful comments and video. I will study this when i have a bit more time. I see you got the same golf as mine and even the color tornado red :). I have done my test so basicly instead of driving for 20 minutes for the rpm's to drop back to normal, i started the car, ran it 10 minutes as it does at 1400 rpm+-, turned it off for 30 minutes and started it again and the idle was perfect ! So, correct me if i'm wrong but seems to me the 3 point unit is just very slow to retract ? or is it is the waxstat thing with the needle that is frozen ? I did change it 10 years ago to a metal one instead of plastic,..Food for thaughts,...Thanks again. Phil.
My best guess, without seeing it, is that the waxstat is slow to react.  So when you switch off the heat from the engine rises up to the carb and causes the wax to melt and push the idle down.  Why its slow to react is a good question (lack of coolant flow perhaps).  Have a watch of my DIY video first.  I describe how the warm up procedure works, and what and how the various parts of the carb operate together.  Once you understand the process you'll be able to understand what is going wrong.  In short, if the waxstat is to blame, there will be a gap between the throttle arm and the 3 point unit.  If its the 3 point unit to blame, the throttle arm, once hot, will be touching the throttle arm. 
There is a useful PDF of the pierburg manual, which shows the various vacuum hoses and what they connect to.  There are also a few other older videos that explain how the vacuum system works, but the short version, is the thermo time value and the solenoid reduce and increase the amount of vacuum that the three point unit receives, to control the position of the 3 point unit.  Any leaks in the hoses therefore mess up the position of the 3 point unit.  I believe you can bypass the thermo time valve and solenoid and the three point unit will always sit in the middle position (hot engine), but of course that makes driving it cold a nuisance as it will stall.
23
Interior, Upholstery & Trim / Window trim
Last post by RichMyers -
Hi. I have started to rebuild my golf that I basically bought in kit form and I am missing a couple of parts from the window set up. Difficult to find but if anyone can point me in the right direction I am missing the piece of trim that goes between the rear driver side 1/4 and the window.

Also two small chrome bits that go on the corner of the front doors in front of the 1/4 windows.

The car is a 1984 and the one where the mirrors are on the doors.
24
Engine & Gearbox / Re: High rpm when cold for 20 minutes,...?
Last post by philip -
Thank you very much for your very very helpful comments and video. I will study this when i have a bit more time. I see you got the same golf as mine and even the color tornado red :). I have done my test so basicly instead of driving for 20 minutes for the rpm's to drop back to normal, i started the car, ran it 10 minutes as it does at 1400 rpm+-, turned it off for 30 minutes and started it again and the idle was perfect ! So, correct me if i'm wrong but seems to me the 3 point unit is just very slow to retract ? or is it is the waxstat thing with the needle that is frozen ? I did change it 10 years ago to a metal one instead of plastic,..Food for thaughts,...Thanks again. Phil.
25
Engine & Gearbox / Re: High rpm when cold for 20 minutes,...?
Last post by Keekster64 -
Ah the joys of the pierburg.  A few things to get us started.  The idle is not controlled by the choke.  Its controlled by the three point unit, and the waxstat.  When you first fire it up it should briefly reach the initial idle speed, about 1400, for a 10 secconds or so.  This is controlled by the thermo time value that adjusts the vacuum and causes the three point unit to stick out as far as it will go, which I'll call position 1, then the three point unit should retract to its middle position (position 2), at which point there will be a gap between the throttle arm and the three point unit as the waxstat will keep the idle higher.  As the waxstat warms up (check you are getting hot coolant flowing to it), it will push a pin which will cause the throttle arm to move back towards the three point unit.  When hot there should technically be no gap between the throttle arm and the three point unit.  Mine always had a gap, but I never got around the adjusting the three point unit.
The fact that it eventually drops to 900 when hot suggests that everything is working but the waxstat is slow to warm up.  To be honest, they are always a little on the slow side to warm up, but I would say 5-10 minutes is probably like normal.  Start the car on the drive cold and watch the carb go through the cycle.  Check to make sure coolant is flowing through the small hoses to the waxstat. 

Position 3 of the three point unit is when its fully retracted, which happens when the you turn the engine off causing a solenoid to close/open, and the total vacuum increases to the maximum causing the three point unit to pull back.  This causes the throttle flap to shut and the engine cuts off.

One last thing.  The choke only controls the mixture.  In my experience they tend to give far too much choke when its fired up form cold.  I backed mine off a bit, cause it ran too rich when I first fired it up, causing it to flood a bit (lower revs). The choke is controlled electronically and via the coolant.  When its cold make sure the choke is getting 12volts.  If not it will be relying on the coolant to warm up and that is waaaaaaay too slow.  Its controlled by a thermoswitch on the top hose to the radiator.  The video explains.

I did a video a while ago that explains all the parts of the carb, that you might find helpful.
https://www.youtube.com/watch?v=taTBdkrQouI&t=16s

26
Engine & Gearbox / Re: High rpm when cold for 20 minutes,...?
Last post by philip -
Hi, may be i didn't explain correcty too lol. So when stone cold, start the car, rpm goes to 1100 ( auto choke i guess,.. ), i start driving and after 1 minute, the rpm goes to +- 1400. After driving for about 15 minutes when the temp is in middle and car hot enaugh, it starts to slowly drop back to normal idle within +- 5 min. To answer your question, yes, at that point if i turn off the car and resart it immedialty it idles perfect at 900 rpm and for the rest of the day until stone cold again,... And yes it should be warm enaugh long before all this,...I am going today to do another test as i might have a theory, not sure. I will drive the car for a few miles, it will idle at +- 1400 still, park, turn it off for 20 minutes and see if it goes back to 1400 rpm immediatly or if it will idle fine. I will let you know,...thank you.
27
Engine & Gearbox / Re: High rpm when cold for 20 minutes,...?
Last post by scs -
Hi I obviously did not word that too well what i meant was as soon as the engine is warm enough not to need the choke if you stop the engine and restart does it run normally. The engine should be up to temp long before 20 mins.