Classic carb icing, the Pierburg 2e2 has several systems to prevent it: 1. Warm air feed, which goes from a metal shroud round the exhaust manifold to the airbox. This is controlled by a vacuum operated flap, so make sure the vacuum pipes are plugged in and the flap opens when the engine is running 2. Heater screwed into the front of the carb (See FAQ link below) 3. Heater in the inlet manifold, only active for a short while after a cold start, deactivated when the coolant is warm enough, (see FAQ link below) 4. Carb & inlet manifold is warmed by coolant from the engine (See FAQ, the bit about the coolant channel o'ring) Have a read through my 2E2 FAQ Post, has lots of usefull info about the 2e2 and all the little bits that make it work
OK, had a go at today at checking all the bits mentioned. I found that the channel heater unit is open circuit so that might pe the problem? Is that enough to cause icing up? Has anyone got a spare unit going begging? I never did find the hedgehog - what the hell is that and where is it? I had full movement of the flap with engine running and it stayed where it was (closed) after I switched the engine off. Didn't check the carb coolant bits though. I hope replacement of the heater will sort it.
oh cool, how do they fix on then? is it just on top of your k&n (pressuming thats your k&n in your sig)
The hedgehog is the inlet manifold preheater, its screwed into the base of the inlet manifold. Theres a big chunky wire going to it round the back of the carb Edited by: rubjonny
I stuck it inside the K&N so that it warms he air and the carb itself. They get pretty hot. Hot enough to burn your hands after a while. Been a week now and no carb icing and able to go off choke in about a mile of traveling so I know it must be doing it's job.
In the winter hot air feed is use practically all the time, so this heated air in the K&N should and doesn't appear to affect my engine in any way. In the summer I will remove the heater. Cold air does give you more power though as the air is denser. Warm air will reduce your cars performance.
Well, I thought I would be OK today as it's much warmer - about 8 or 9 degC - but I'm still having trouble. The engine tried to die going up hills twice this morning, and once just ambling along the flat at 50 or so. OK, I have identified that the part throttle channel heater is open circuit, but even so I would've thought that I wouldn't have icing today anyway . I have a few tests to do first, but I'm inclined to do 2 things initially - start using super unleaded (95 U/L in at the no), and try and place the cold air intake away from the front i.e. point it towards the engine. Ant thoughts folks? I'm feeling pretty desperate as I'm relying on this car to go away next week
It is still cold enough for carb icing to occur, I've had it on much warmer days than this. Its more likely to happen if there is moisture in the air too. Check this tech info I found on the subject: Edit, take the cold air feed to the wing off, or just bodge the warm flap fully open with a self-tapping screw Edited by: rubjonny
I'm confused about the flap arrangement - how does it work? Does it not open to cold air as soon as you get a vacuum or is it controlled by something else
doesnt it get controlled by a temp regulator inside the airbox? the vac pipe goes from the carb via this regulator to the flap. im not sure when exactly it allows/shuts off vacuum though....anyone know? or am i talking pooh pooh
I guess as the engine warms up the sensor allows the vacuum to open the flap a bit more to allow more cold air in - so it's normally (when cold) closed to cold air and just takes air from the exhaust manifold pipe?
The sensor in the side of the airbox detects the temperature of the air passing through and regulates the flow of vacuum through it to the flap accordingly
penny's dropped now - I bodged the flap permanently on hot air until I can replace the channel heater, hope that works, find out lateer - thanks all..
Still no joy with this problem. I'm going off the idea it's icing aas it's dying when cold now. Gonna check for pooe in the tank...filler neck?
The filler neck on Mk2s are plastic so they don't rust & let crap in like the Mk1's. Could still have crap in the petrol though. Is the carb flange in good condition - these crack & let air in leading to running problems
Did you check all the other stuff in my FAQ post? Mikey are you refering to Golf MK2s or Sirocco MK2s? Daviddd is having this issue on a Scirocco, dispite his sig pic BTW if it was carb icing its more likely to die when cold rather than warm Do you have any other symptoms? Over-reving, running rich etc? Check your plugs too, what condition are they in? Edited by: rubjonny
