Hey guys, been having issues with my 1991 1.6 Mk2 over Xmas. its got the Weber fitted, but this was already on there when i bought the car. First problem was that it wouldn't start at all at the end of December. Turned over fine, seemed to be getting fuel etc and checked 1 of the plugs for a spark. After a lot of fiddling with my hand in the air-box to push the choke flap and jump starting etc, it started. 30 mins down the M3 and it wouldn't accelerate unless my foot was on the floor. Which wasn't a problem until i got to a roundabout and had to pull-away! took it for a few local runs and sometimes it was ok, and then the fault would return. if i kept my foot static it would lurch and bog and sometimes stall. then I'd get round a corner and it would be fine again... so far i have: -changed fuel filter -changed air filter (was a bit wet and needed doing anyway) -replaced vac line from Weber to air-box cold air flap (which was seized but i have now lubed) -replaced hot air ducting from manifold to air box -removed Weber and sprayed with carb cleaner. checked all moving parts and lubed springs etc. -removed each jet and checked for blockages After fixing the air-box hot air intake, the car started (eventually) and was running great for about 3 days. This lead me to assume it was all down to icing and that by re-introducing the hot air feed and fixing the cold air flap on the snorkel, I was all good. Went to start the car this morning and again, it wont start at all, even with some start spray (was -2 outside) only thing to note is that whoever fitted the Weber, hasn't taken the Pierburg throttle body heater off and put it onto the Weber- so that is missing. I have had a look around, and seen other posts regarding sourcing one but this seems almost impossible! So on my list of things to check now is: -inlet manifold preheater and related red topped temp sensor -check each spark plug for a spark -check earth points Anything i am missing here? The car has been running faultlessly all last year, and the only similar issue i have had was when my Alternator was sending a much higher volt to my battery which gave me similar, lurching acceleration, so the Alt and battery have both been replaced and running fine since. the Alt was the first thing i checked this time around, and I'm getting 14.5 volts under load at the battery.
FWIW I have recently fitted a Weber on our 1.3. I'm happy to say it works very well. I don't think icing is your issue if it won't start from the outset. I would deffo check that the manifold heater is connected. My Pierburg did not have a throttle body heater and there doesn't seem to be anywhere to fit one on the Weber. Are you sure you don't mean the cut off valve? As mentioned on another thread do you have a swirl pot? The recommendation there was to remove it and connect the pipes directly with a restrictor in the return line. This is what I have. I'm assuming yours is manual choke. If so are you sure this is working correctly and you aren't flooding the engine? I'm sure those with more knowledge will be along soon.
Thanks for your reply Phil. Yes, there is a specific mounting place on the Weber for the heating element along with a threaded hole to mount it, and i remember having to switch it over on my last golf when i did the conversion myself, as it was detailed in the Weber instructions. I do have a swirl pot, as it happens i have a new replacement one ready to fit. what do you mean by restrictor in the return line? i have a spare non-return in line valve sitting here, but I'm not sure you would call it a restrictor. Yes, manual choke. Checked that it operates from interior lever to the butterfly on the carb and it does indeed close completely when engaged.
Mine closes completely. I don't think that is completely correct but it still works. I do find that once started, almost immediately, I have to let the choke off quite a bit. It's fully off within a mile even in these temps. I think the normal procedure (it was in my instructions) is to do away with the swirl pot and put a Y piece in the fuel feed which connects to the fuel return. On the return side of the Y piece is a restrictor to prevent too much fuel returning.
hmmm, ok. Maybe i'll pop the new one on and see if that fixes the issue. it seems unlikely that the swirl pot is preventing the car from starting though? from my understanding, the swirl pot is to allow a constant feed of fuel when cornering?
what symptoms/problems where you having that this fix resolved? and where did you source the parts for the fix?
I didn't, I just followed the instructions and all the parts were included in the kit. All i was doing was replacing the ancient and complicated Pierburg. See here for the other thread i mentioned. https://clubgti.com/forums/index.php?threads/1-8-gu-weber-32-34-sluggish.290645/#post-2493129
To be fair, looking at the kits available for the 1.6 they don't seem to include the Y piece. It may be worth e-mailing eurocarb for the instructions and see how they match up with your install. They were very helpful to me when i did mine.
yes, i'm lookign on their site now and i cant see that part either. I certianly dont remember discarding the swirl pot on the conversion i did on my last golf. i guess i'll pop the new swirl pot on anyway as i have one.
yes for 1.6-1.8 you're supposed to leave the swirl pot in place, sometimes the factory fitted restrictor in the pot goes missing and the usual fix for this is insert a welding tip in the return to sort issue. you can temporarily remove the pot and block the return to see if it helps. but having said that if easy start didnt get you anywhere doesnt seem to be a fueling issue. plus as mentioned bad starting from cold wouldn't be helped by fitting a carb heater either since it would take some time to get up to temps, though you should try to source one anyway i would have a look at the rubber flange between carb an inlet, plus make sure the steady bracket and rubber bobbin is fitted to the front of the airbox to stop the carb flapping about too much
Hey Jonny, The rubber bobbin is certianly fitted as i replaced it about 6 months ago, i did wonder about the carb flange as i know it can take a bit of a beating. Would this prevent the car from starting on a cold day though? whats the simplest way to test the flange when i cant start the car? have someone apply some downward pressure on the top of the carb/airbox to temporaraly seal any leaks?
generally what you do is give the carb a good wiggle while its running, and try spraying easy start round it see if the idle changes in either test. pressing down hard would help seal any splits and could explain how you managed to get it going after lots of faffing... may be worth pulling out the sender unit in the tank make sure thats all good, but again if easy start didnt get you anywhere... I would have the plugs out and see how they look, might be its flooding right away for whatever reason
thanks Johnny, i'll give her a wiggle.. Do you know the part number for the flange? the one i am looking at on ebay says it isnt compatible with 4 bolt carbs...and i remember buying one in the past for a conversion and it was wrong... yes, i plan on pulling all the plugs and seeing how they look too. been meaning to get the Gunson on there anyway to tweak the carb settings.
Hey guys, so, had the plugs out. they where very wet and pretty grim so replaced all four and the car started. swapped out the swirl bowl whilst i was there, and replaced a few vac lines. I also adjusted the idle and mixture on my Weber using a Gunson Colourtune and took it for a drive - spot on. this was yesterday. got in the car just now - same again. wont start. Can i assume this is now down to engine flooding? whats my next port of call?
maybe you have a weak spark issue? next cold start check voltage at the coil both ignition on and while cranking. check the wiring over for the spark module in general, connection to battery, coil terminals all clean, peel back rubber grommet on the distributor & spark module to check wiring in the back of the pin crimps is good plus pins themselves are clean and fully inserted into the plug. check quality & condition of the plugs, leads, cap and arm. I would only use bosch or beru ignition components, plugs same plus ngk and champion are oem fit also. this is where ~I usually shop for this kind of thing if not ebay: http://www.vwspares.co.uk
