Is your throttle cable length set to correct length / setting as per rob and dave ? http://www.vw-resource.com/accelerator_cable.html#adjust This can cause hesitation ,have a look if you havnt already
Would be better if you got your warm air feed working. The heat risers are likely well bunged up (as everybody's are): I wouldn't say they make much of a contribution, meself. The air cleaner either breathes cool-ish air through its "snout", or hot air from around the cylinder heads via the pipe through the tinware. The air's deflected by a flap that's operated by manifold vacuum. The vacuum is switched by a thermostat in the air cleaner (the bit that @scrooge95 mentioned). Pretty straightforward if you take a look. Best to have it working, as the engine doesn't like breathing hot air after it's warmed up.
Found this, after a lot of searching: On mine, the vacuum flap control pod is missing, as I mentioned before. The strange thing is that the flap itself (red in the pic) is completely stuck in the up position So the engine is only getting warm air. Now I’m really confused.
It takes about 3 miles driving for the air to reaching the carburettor to be hot enough to improve/remove hesitation. Then if the flap is stuck the engine will possibly switch from lean hesitation while cold to over rich liss of power when the air gets hot. The carb vacuum hose goes to the distributor its ported so no / little vacuum at idle or WOT but only while accelerating. The manifold vacuum is high at idle speed from below the throttle plate and reduces as the throttle opens. At WOT it is basically a bit below atmospheric so the hot air flap drops closed increasing engine efficiency at high speed. As soon as you take your foot off it goes back to high vacuum and feeding warm air for idle and killing flat spot. The expensive little switch stops vacuum to the flap so the intake to the carburettor never exceeds 30 degrees C. On a cold day it does nothing (except maybe leak totally) so connecting manifold vacuum direct to the flap actuator should work. Somebody has wired up the flap I suspect. Un clip the capsule underneath the cold air intake to get at the actuating mechanism.. maybe though its like mine which broke when I finally got it working. It thumped down so hard with the vacuum .. So I made up a spring out of springy wire and reattached the actuator to the flap.
Helpful info. Thanks! Unfortunately, the capsule on mine is missing, and I’m pretty sure the flap has rusted/been painted closed or something—looks like it was welded, but I can’t imagine anyone bothering. I think I’ll replace the whole can with one that’s in better shape. Need to get a fitting put on my manifold too: it’s been removed and sealed.
Ah my apologies, I thought you meant that the thermostatic valve was absent (number 5 in the pic) but I see you are talking about number 3 ^^^ There were a few whole units on ebay when I was looking for a replacement valve, around the £50 mark if I recall correctly.
I had a quick look today whilst @Tony boone was messing around with your seatbelt mounts . I`ve done my back in so couldn`t get down an` dirty but after a feel around , the choke wasn`t closing fully , maybe open 15-20mm down the front . A simple adjustment by loosening off the 3 screws should help things
My hot air flap was welded shut while I owned it in 2000 by a mechanic in London. He was a Kiwi with a big workload fixing bays for antipodeans travelling around Europe. Looks from the thread that welding it shut wasn't the best idea so I've replaced mine. I found it was defective and probably so did Grant the Kiwi mechanic. http://www.thelatebay.com/index.php?threads/oil-bath-air-filter-pipe.67375/#post-1243971 BTW I replaced the actuator with a second hand one. I haven't been able to test the temperature at which the replacement actuator opens to let the vacuum through very accurately. Does anyone know if the screw on the actuator holding the little plastic ball in varies the temperature at which it opens or not? It seems to me to vary the vacuum going through but I wonder if turning that screw might set the correct temperature. I thought I got it working using a hairdryer and then connected in the garage but went for a drive on a very cold day recently and it didn't open the flap to let the cooler air in after a short journey. Couldn't get it to open using my armpit either!
Well, if you leave yours with Tony any longer he’ll install one, probably fabbed out of magnesium billet, just as soon as he’s done shoehorning in a 427 V8 and . . .
Ah! My van’s also a west Londoner and I know the PO took it to Jack’s Garage, so maybe Kiwi Grant got at it too. That explains a lot. Complete bodge job, but I know these guys are often on owner-mandated tight budgets. I’ve got a replacement cleaner on the way. I hate not having things working properly. Next I need to get intimate with the Chelsea tarmac and make sure my thermostat and flaps are functional. I’m going to hazard a guess nope.
I don’t know, but wouldn’t the thermostatic valve only open at colder temps. I would expect it to be open below maybe 10°C or so. So it would already be closed in your garage, no? And a hair dryer or armpit would only cause it to remain closed. Try popping it in the fridge and then letting it warm up to room temp. (Caveat: it’s early and I’m under-caffeinated.)
I wouldn't fiddle with the adjuster - you'll regret it . When I had an original (paper) airbox, on chilly days the flap would take a surprising amount of time to open...
It's supposed to open when it gets to 30° C to let in colder air through the "snout" rather than from the cylinder heads via the stovepipe I think. In fact I think mikedjames answered my question already to some extent above saying "On a cold day it does nothing (except maybe leak totally) so connecting manifold vacuum direct to the flap actuator should work." It was a cold day so maybe the actuator never reached 30° I know snotty I thought of that but I had 3 actuators from 3 different air cleaners and none was open at room temperature. I managed to clean one out by removing the ball and adjuster but didn't really have any option. I do regret it but I'm still trying to avoid the £58 for a new one at the minute...
30° seems kinda warm. It’d never reach- wait, are we talking in Celsius or Fahrenheit? (edit: never mind. You said Celsius)
I saw complete oil bath air cleaner assemblies on the mega-bug junk stand outside the grandstand at Volksworld for £10 each last year. Next to the secondhand aluminium degree pulleys with half the markings rubbed off for £4.
