Hi, well it's bizzare, tested the car this morning, idles at 1100 rpm for 15 minutes then goes back around 900. After leaving it to cool down an hour, it starts and idles way too low at +- 600 rpm for about 10 minutes. I think i'm going to leave it be now and stop fiddling as there is a big improvement in any case. Thank you all for all the help and especially the video you sent me that was so usefull to learn about the cab,... the old girl got 89000 miles, first owner from new. I wanted the GTI but couldn't afford it so got the last 1600 cc Driver without power stearing lol.
Thanks again,
Phil.
Glad you found the video useful. There is so little info on these carbs, and it took me a while to figure out how it worked, so I wanted to share the knowledge. Its fair to say the carbs are rather over engineered, and not particularly resilient. I had a 1990 Toyota Carina for 7 years, before I bought the 91 Driver. The Toyota had a carb that worked so well from cold it used to surprise me that it didn't have fuel injection. It was flawless. It makes you wonder if the japanese could design a carb to work so perfectly, why cant the europeans!!
At the moment I'm running the supposedly better Weber. Its not true. Its better than a knackered Pierburg, but its a crude carb which cant deliver the fuel efficient running the pierburg can deliver. I've done another video on it. Its flaw, in the 1600, is the accellerator pump jet. The web con kit has the same jet for the 1600 and 1800. Why? Because its the smallest one they do. It mean it delivers too much fuel when you floor the throttle, cause it to stumble before it accellerates. It can also cause the engine to stall at idle if you blip the throttle. I have managed to improve it though. There is an external arm/cam wheel, that controls the amount of fuel. I used a dremmel to take 1mm off the cam which has the effect of reducing the amount if fuel the pump jet delivers. Its a lot better, but its still a little on the rich side, but it does the job. Its also harder to start from a warm start, as the idle and the choke are controlled both by the choke cable, and the idle only increase when you pull the choke out most of the way, i.e too much when warm.
yes sorry i did test the coolant hoses and they are getting hot. I was just about to ask if it was worth it to take it out and do the boiling water test in the hope of a miracle or improvement,...lol. I will do this over the weekend as at the moment weather here south east not the best,...If i remember well, I only have to take the air filter housing off to get easy access ? thanks again, fingers crossed as this problem just suddently started 6 months ago.
Yeah, just remove the airfilter and disconnect the hoses at the choke and the coolant pipe. On the video I mention how many milimetres (cant remember) its supposed to stick out when its fully heated up. I did my own one using this method. Sadly a year later it started to leak. Finding one in good condition is tricky.
Another test done, turn on the car, idles at 1000 rpm, drive 1 minute, shoots up to 1400 rpm, drive only 10 minutes, come home, still at 1400 rpm. Turn it off, start right away, back at 1400 rpm. Turned it off, waited 45 minutes, start again, idles perfect ! It must be the waxstat ! I'm looking to buy one again but they seem to be impossible to find now. I only found this website but it's out of stock and frankly expensive anyways as i did change it over 10 years ago and i wouldn't have spent that much i'm sure,....Any ideas where i could fetch one ? Thanks. https://www.classic-vw.co.uk/pierburg-2e2--2e3-carb-wax-stat-026129243c-7716-p.asp
I'm assuming you touched the coolant hoses to the waxstat to check they are getting hot, as you dont mention it? That aside, I would removed the waxstat, complete with its hoses (when its cold) and submerge it in a cup of boiling hot water. You should see the metal pin in the centre push out. This is supposed to reset it, ie, without spring pressure restraining it. If it leaks wax or coolant from around the pin, its knackered. If not, then refit it and see if it improves.
Whilst I remember, there is a rubber seal between the intake manifold and the cylinder head. When they get old they swell, and this can restrict the flow of coolant to the waxstat. Eventually they can break up and get stuck in the intake manifold and block it. To check make sure the hoses to the waxstat are increasing in temp at the same rate as the top radiator hose. If not you may have to remove the intake manifold. I did it recently and its deceptively tricky. You need the right tools to do it.
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.
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.
You should be getting 12 volts at the coil. I'm not sure which terminal though, should be the positive one. Check your fuses, and I'd recommend having a look at the wiring diagram in the haynes manual. I've used it a few times and its very helpful. You may have a broken wire.
Thanks very much, I have the haynes manual for it so i will find that wiring diagram
If you are not getting current to the coil, you could try bypassing it and feeding it direct from the battery (temporary), to see if it starts. However, you'd need the haynes manual to identify the correct terminal on the coil
You should be getting 12 volts at the coil. I'm not sure which terminal though, should be the positive one. Check your fuses, and I'd recommend having a look at the wiring diagram in the haynes manual. I've used it a few times and its very helpful. You may have a broken wire.
The mixture screw on the top of the pierburg carb only adjusts the mixture at idle for emissions purposes. It works the reverse of most carbs i.e. to lean the mixture you screw it out (anti clockwise) and to richen it you turn it in (clock wise). If you car is running rich, the mixture may not be the cause. Make sure the choke is fully off when the engine is hot for example. The idle speed should be 850-900rpm, when fully hot. There are a number of way of adjusting the idle speed, some which are incorrect, but people do it anyway. I suggest down loading the pdf of the manual for the correct way of adjusting it.
Note the metal clip holes the back piece to the top of carb. If you have a Weber, it bolts on to the carb through the small round hole. The front piece clips to the rear piece and the rubber bit bolts to a metal bracket
. 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.