More carb worries!

Hi, I've been having a few embarrassing carb situations since the colder weather set in, and have been through the explanations on here, which are clear and helpful.
This resulted in my removing the manifold, bead blasting in inside and out, and refitting with a new O-ring.
I've just worked out how to adjust the 'spring' cold start mechanism by turning the housing, so that should be solved, but I've still got two missing connections. The first is an electrical solenoid next to the accelerator pump, which doesn't seem to be present on the pics in the sticky thread. It's the light brown housing, on the first photo:


My question is what should be plugged in to this part - I don't seem to have any availible wires in the vicinity except the lead which goes from the base of the carb to the rocker cover.

The second missing connection is a vacuum pipe, from the air filter housing. According to the sticky it should go to the back of the carb, but the pipe on the back of the carb is already connected to a Y piece which joins the dizzy via a filter and the top of the black Pierburg housing.


I've seen a sort of globe connected to some carbs, on the bulkhead. Is this what I'm missing?

Any help much appreciated.

Robin

the solonoid is the carb heater. i can see the wire for it is plugged into a spade connection on the rocker cover. it takes an ignition live feed so you have probably blown the fuse for the carb heater now
the spade on the rocker cover should be connected to a wire that runs to the top of the carb, its just an earth for the carb body.

the vac hose in your picture does go to the back of the carby, look again in the sticky thread, the connection for it is the one i have circled in red on the picture of the back of the carb

Ok Thanks for that. I'll reconnect the carb heater ang check the fuse. The vacuum pipe at the rear of the carb seems to be already connected to the Y piece. Are there two small pipes on th erear of the carb?

Robin

yep 2 connections. like I said look at the vacuum diagrams again

I've checked the fuses, none is blown, so I'll have a lok at the wiring. Does it need a 12v feed from the ignition? For the carb earth, can I simply fit a wire from a bolt on the top of the carb to the tab on the rocker cover?

My main worry at the moment is the high idle syndrome, which is at 3k rpm for a good ten minutes until the engine warms up, but it isn't coming from the water channels, as I've sorted them out.

Should I think abour a radiator blind to speed up warmup?

Robin

yerah its just an ign live feed to the heater, and the earth theres a screw on the edge of the carb but any good metal contact will do.

the high idle could be the 3/4 point unit, you can clearly see it in your pic with the plunger in the fully extended position. start the engien and watch it, the plunger should retract to around 10mm within a few seconds. if not switch the engien off and switch the ignition on and listne very carefully. you should hear some clicks from the 2 electrical valves on the back of the carby. again you can see them there clearly! both of those 2 pin plugs should also get ign live. if you shorted or melted the carb ign live feed when you put the carb heater plug to the rocker cover that probably disabled both those valves at the same time

OK Thanks.

Both the connections on the back of the carb are connected - the one I think I need is connected to the Y piece. What should the Y piece be connected to?

Also, I've been through the very good fuse location diagrams, and I can find a relay for the inlet manifold heater, number 1 in position2, but no fuse for the carb heater. Would it be the same relay? Do you have any idea which would be the corresponding fuse?

Your help is much appreciated.

Robin

look at the vacuum diagrams, I carefully coloured them in for you even to make it easy

try fuse #17, thats what shows as the heater and vacuum unit fuse in my mk2 golf haynes. check #18 as well while you're there

Thanks again - it looks like I'm missing the vacuum reservoir and it's pipe is connected where the filter pipe should go. I'll take a trip to the scrappy tomorrow.

Robin

aha yes you're right, i can see this in the first picture

Ok,some progress has been achieved, but it's not right yet.

I've been to the scrapyard and picked up the missing bits for the vacuum lines, cleaned and fitted the reservoir and the lines in the correct places, with new flexi hoses on the ends, and fitted an earth strap to the top of the carb, which runs to the tab on the rocker cover.

I also picked up some more temperature sensors to test, but I couldn't find a grey one…

My two sensors, red and grey, after cleaning and testing, were both isolating whether hot or cold, so I binned them and fitted a good red sensor (with 55°c 65°c printed on it) I need to find or order a grey sensor, since the others I found (black or blue) are sensors which switch on when hot.

With the grey sensor shorted, and ignition on, there's still no movement or click from the 3/4 Point Unit, so I need to look at finding another one of those too.

Car is still running fine, just takes a long time to reach sufficient temperature to switch off the idle control.

More soon,
Robin

the sensors only do the carb heater and inlet heater, nothing to do with the 3/4 point unit
the 3/4 point unit is controlled by the 2 electrical valves round the back of the carb, you should hear a click from back there with the ignition

RobinFromFrance said

I need to find or order a grey sensor

Ive been searching for one of these aswell :dontknow:

worst case you coudl use a red one, better than nothign anyway. VW still sell both though!
251 919 369 B - thermal switch, red - 10.23+VAT
191 919 369 B - thermal switch, grey - 10.23+VAT

rubjonny said

worst case you coudl use a red one, better than nothign anyway. VW still sell both though!
251 919 369 B - thermal switch, red - 10.23+VAT
191 919 369 B - thermal switch, grey - 10.23+VAT

I assumed they would no longer sell them! Part numbers and prices aswell  :mrgreen:  ill add it onto my ever growing list of parts I need to get from VW.

If I ever meet you i'll buy you a beer! . :wink:

rubjonny said

the sensors only do the carb heater and inlet heater, nothing to do with the 3/4 point unit
the 3/4 point unit is controlled by the 2 electrical valves round the back of the carb, you should hear a click from back there with the ignition

Ok, thanks for that. I've tested the power leads, and only the rear socket is getting power, the front lower one isn't getting 12v at all.

Can I remove and test the 3/4 point unit? Is it simply a question of running 12v into one of the tabs on the socket? Which one is 12v in and is the other an earth lead?

Sorry about the question, but my Hayes manuas shows a black wire to each socket for power in, but the second wire isn't shown.

Thanks again,

Robin

all they need is ign live and earth, check all your fuses to start with though iirc both valves get 12v from the same place so it could be a break in the wiring or the earth is bad.

the 3/4 point unit can be tested off the car, you need a length of vacuum pipe and some suction. your mouth works if you dont have a vacuum pump

I cant remember off hand which way it works, but iirc you suck on one of the pipes and it should retract to running position, then block the other pipe with your finger and carry on sucking and it should retract all the way. also it should hold vacuum when you put your tounge over the end of the pipe.

the haynes covers this in more detail, also see the 'haynes2e2manual.pdf' in my sig