Hi folks, I cant work out how to add to the Pierburg carb discussion so I'll start here and hope someones reading.
Just bought Scirocco 1.6 GT 88 on an E, cost peanuts as it cuts out after 10 mins or less, coughs, splutters and dies only to restart promptly. Classic symptoms of carb icing as experienced on numerous similarly equipped VWs in the past (Mk1 Scirroco GLS, Mk1 Passat, Audi coupe gt5 carb etc etc)I plan first to try and eliminate this by just taping up the intake for cold air. But to add to the fun I find that the little green vacuum hose that feeds the green sphere has collapsed, what's this for? and, more interestingly the filler neck has done the usual rotting out trick..... which may have allowed water ingress from wheelarch.
This has caused me problems before and very similar to carb icing, ie car revs badly, cough and dies, only to restart once float chamber has been refilled by pump. The fuel filters get blocked by water... this can happen on injected cars too. Re someones concern about injected icing, never seen it, consider it unlikely as the wet bits (injectors) are right in the head and kept warm. A warm air tube is therefore not present, only the ducting from the airflow meter/fuel distributor (depends which K jet or digifant)
Question...has anyone else experienced fuel contamination like this and do they reckon it gives the same symptoms as icing? (before I take out the tank sender and manually drain the fuel system).
GTi's wise Where's the oil pressure relief valve on a Mk2 Digifant golf? I keep getting buzzer and lights have replaced big ends, oil and filter but not mains which thump a bit whrn warm (I know, I know, it's a bodge but the cars pretty much kippered and I don't want to go mad on it)
Incidentally, I'm not going mad on the pierburg either, I've got a twin choke weber sat in the shed waiting for its chance!
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Carb icing is easily solved by making sure the hot air feed from the exhaust manifold area is attached, and the little flap which controls the cold/hot air mix is not stuck. My mate's polo had this problem when he fitted his weber carb and it was a total knightmare until he refitted the hot air feed - cold air is not always better!
I think the green ball thing is a vacuum resevoir (thinking back to an old Audi 80 GL), which controls the secondary throttle on the carb.
I had an 80 sport with K-Jet and never experianced any problems with 'injector icing', seems fairly unlikely to me as the fuel is blasted out at reasonably high pressure. K-jet can be a knightmare to debug - check all of your vacuum hoses plus air by-pass valve.
Not sure where oil pressure relief valve is, all know is that the warning light on the 80 used to flick on and off (with buzzer over 2k) but the oil pressure gauge used to show full pressure. Not sure whether the switch was faulty or if the gallery to head (where the switch lives) was blocked. Not sure where the sender for the gauge was but it was a fairy responsive and accurate gauge as I recall. Think there must have been a problem somewhere as it gave up spectacularly on the M1 one night! It had covered 220k miles though...
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MMmmm intersting, thanks Tony, makes sense about the green ball as it doesn't have much grunt so 2nd choke may not be working. Oil light thing is intriguing, I'll rig up a gauge to the sender port on the head and we'll see what we get.
Anyone know what pressure the light/buzzer is triggered at?
Shame about your 80, I don't fancy being stranded by a meltdown, although it might be funny at a track day!
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Duzza,
Assuming the engine is the same as the old 80 Sport (code DY or DZ), then the buzzer is triggered at 1.8 bar at > 2000 rpm.
My old 80 Sport (1985) developed this fault at 80k miles. I replaced the combined oil pressure sender/switch on the top of the oil filter bracket with two separate items and a banjo bolt - never had the warning again.
HTH,
Ian.
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Thanks for the replies guys, here's where we are:
Scirocco carb, stuck some gaffer tape over the cold air tube so it only sucks hot....cured.... Looks like I got to the filler neck just in time.
Golf GTI oil pressure....there isn't any, that's why the light and buzzer come on! I put a gauge on it via the cylinder head oil pressure switch hole, got a good 90 psi cold which slowly dropped off as oil temp got up until it got to the 100 degree mark when oil pressure is nil at tickover and about 2psi at 4000rpm accompanied by nice rattly main bearings. I reckon as the oil thins we're losing too much via the worn mains.
Anyone ever tried to do mains in situ? can you move the crank down far enough to get the upper shells out?
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>>Anyone ever tried to do mains in situ? can you move the crank down far enough to get the upper shells out?
If you're keeping the car, aren't you better to get the crank out and get it reground. Do the big ends at the same time.
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Anyone ever tried to do mains in situ? can you move the crank down far enough to get the upper shells out?
I've done it, but only on engines which have separate crankshaft thrust washers. If the thrust washers are integrated into one of the bearing shells, you'll really struggle. I found that by loosening all the bearing caps slightly, I could then remove one cap at a time, rotate the upper shell round the crank until it dropped out, smother the new one in oil and then carefully rotate it into position. But you need perfect cleanliness which is hard to achieve when you're crawling around underneath an old Golf.
Given your oil pressure readings, I reckon that if the problem is shot bearings the crank will be scored, and the new mains will last about ten minutes. I wonder whether your engine has the same problem as an Audi 80 I once owned - black gunge in the sump due to lack of regular oil changes, which is floating around and gradually blocking the oil strainer in the sump. These are pretty tough engines, and if you drop the sump and clean it out thoroughly with paraffin, you might find your oil pressure returns. But I don't know for sure. The diagnosis on my Audi was posthumous, after the engine put a rod through the side of the block.
Richard Hall
bangernomics.tripod.com
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filler neck corosion is a now fuel system killer. change it quick small filings will be drawn into the carb killing it.
pierberg probs green sphere is for holding vacumn so choke pull down and 2nd choke will open. these carbs can be relible if carefully set up. my old mk2 1.8gl golf used to do 30 ish mpg with careful driving. oil pressure switches low pressure one on gearbox side of head. high pressure on oil filter housing.
check thin earth braid between coil mount and rocker cover as if this is knackered this will give same fault.
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