1.8l carb issues: oil in the airbox, sticky throttle
Posted
#1414452
(In Topic #186221)
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I've cleaned it all out with a bit of rag but it just recurs. The air filter isn't saturated with oil, but it's present all along the lower edge of the rubber seal. I assume it's coming from the crankcase breather, but why so much? Don't think it's overfilled, the level's in the centre of the dipstick…
The engine's been running a bit fast (combination of a sticky throttle cable with a poorly-adjusted idle - doesn't seem to respond to the idle screw on the carb, but maybe I've been tweaking it wrong?) and it's had a fairly long motorway run back from Europe at 3000-4000rpm, but it happens in town driving too so seems to be here to stay.
Any ideas? Not hugely keen on getting used to smoke from the engine bay, as you can imagine! Stone
Last edit: by Stone
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
Posted
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See these examples:
Stone
Last edit: by Stone
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
Posted
MOTY 2013
anyway yes you will see some oil in the airbox this is normal, if the breather mesh (if fitted) is blocked it can make the block breathe a bit heavier but the trouble is if it has a mesh these are next to impossible to clean as they are multi layered mesh stacked together. some have had success chopping out for proper cleaning, or getting other random mesh and welding back in.
if its leaking out the airbox tho it could be its loose or seal is missing
Hello my name is John and I'm a dub addict.
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Posted
Local Hero
1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 317,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.
Posted
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It also needs to run in P or N for 10-20 seconds when first started, putting it into a driving gear stalls it - again it runs fine after it's slightly warm.
Would it be worth pulling a bit more of the choke inner cable through then, so it's tighter? Wondering if it was left that way to account for the non-returning throttle arm. Operating the throttle lever progressively, the choke butterfly opens at the end of its travel so that seems to be working as expected.
The airbox was all replaced by CQ recently as the previous one's front rubber mount was snapped off.
Is there supposed to be a seal between front and halves of the airbox? I only have the rubber lip around the air filter sandwiched into that gap at the moment. I guess if there's an air leak it has to be upstream of the carb to cause increased idle speed, so the seal between carb and airbox is propbably ok. The top bolt holding airbox to carb is definitely wrong, it's just a regular hex bolt and (bent) washer when it looks like it's supposed to have a top-hat washer - might see if I can get something machined up, but I don't know if that would improve the del. Might stop it vibrating loose, mind…
Stone
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
Posted
MOTY 2013
the EW/EX airbox it would be clipped on originally but since you have a weber you loose the clip and instead it is bolted down, the proper hardware is like an odd T shape nut that threads down onto a stud on the bracket. its shaped this way to slip nice down the hole in the airbox and tighten fully to the bracket, if you dont have this then a self-lockign nut should help or find a sleeve that drops down the stud so a nut and washer can tighten proper
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
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Posted
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I don't have the correct fixing hardware up top, just a bolt and washer - if it's vibrating loose it might explain why it gets a faster and faster idle over time - thought it could have been a heat issue…
I have two single piece clips on the top of the airbox and one jointed one either side, is that the right number? Maybe they're not holding the halves tight enough as the oil drip is from the bottom.
Stone
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
Posted
MOTY 2013
a self locking nut should stop it working loose, but the worst thing that can happen with a loose airbox other than rubbish getting in the carb is the warm air feed will loose vacuum and eventually you might get a bit of carb icing, it wouldnt affect the idle really
the clips all sound right, probably just too much oil to seal against affectively. you could get yourself a catch tank to stop the oil, I rigged up a milkshake bottle temp just to see if crank case gasses were affecting anything. once it was clear it made no difference i put it back. as i say maybe the mesh in the rocker cover if there is blocked causing excessive breathing?
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
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You'll need to sign into google/gmail for the link to work! (its free!)
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Adjusted the choke cable a little - runs a little better now but the outer cable's not clamped very well, feels like the thread on the clamp may have stripped. Hoping a new spring, seal and air filter might calm it down a bit, if not I may just have to live with it
Stone
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
Posted
Settled In
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
Posted
Local Hero
Set up of choke cable and the adjustment of the screw (circled in red) which when you pull the choke cable out increases the idle speed by opening the throttle, there is a light gap so the screw is not touching the throttle adjustment when the choke is off but it's not easy to see in the photo.
Set up of spring, it was orginally attached in the little hole but after a couple of years it started to make the hole bigger and I thought it might wear it's way through the metal to moved it to the bolt which holds the accelerator cable but just keep an eye on yours.
As for the dipstick tube have you got a picture of what type of dipstick you have, a picture of it in the engine and out of the engine would be good?
I've one of those tubes on my Golf but not one on my Scirocco so you may not need it
1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 317,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.
Posted
MOTY 2013
edit: they came in 31/7/1983 onwards
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
Posted
Settled In
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
Posted
MOTY 2013
Hello my name is John and I'm a dub addict.
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
My wiring diagrams and other documents have moved here:
VAG Documents & Downloads
You'll need to sign into google/gmail for the link to work! (its free!)
Posted
Settled In
The warm air flap vacuum feed seems ok - putting a finger over the end when it's hot it alternates between very slight vacuum and a bit stronger, so I guess that's probably ok? Haven't checked the actual flap yet, maybe it's gunged up and stuck closed?
The airbox is still secure to the top of the carb so I don't think it's vibrating loose. Will be taking it all apart for a clean and a new air filter later but I'm not wildly hopeful…
I've also gained an intermittent rattle / knock underneath somewhere, had trouble with the middle exhaust mount before so hopefully it's just loose? Doubt the engine mounts are very happy either, the dieselling when I turn it off and the surging can't be doing them any good!
Stone
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
Posted
Local Hero
I'll try and find it….
Found it, does this sound likr your problem?
http://sciroccoregister.co.uk/carforum/viewtopic.php?f=12&t=15397&p=108435&hilit=Restricting#p108435
Last edit: by mark1gls
1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 317,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.
Posted
Local Hero
Stone said
Doubt the engine mounts are very happy either, the dieselling when I turn it off and the surging can't be doing them any good!
Stone
What do you mean by "dieselling when I turn it off"?
1988 Mk1 Golf GTi Cabriolet 1.8cc DX, K-jet. Daily drive. 317,000 miles and counting
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.
1978 Mk1 Scirocco GLS 1.6cc FR, Webber carb. Weekend toy.
Posted
Settled In
That does sound exactly like it, actually. Not sure why restricting it would help though - and why are people removing the vapour separator also? Wouldn't VW have left it off if it was unnecessary?mark1gls said
Just a thought but I did read somewhere about restricting the fuel return to fuel tank?
I'll try and find it….
Found it, does this sound likr your problem?
http://sciroccoregister.co.uk/carforum/viewtopic.php?f=12&t=15397&p=108435&hilit=Restricting#p108435
When I turn the ignition off, the engine stops, then coughs a couple of times and either stops completely or comes back to life, runs really rough for another second or two and then stops. Since the coil's disconnected with the ignition off, the spark plugs shouldn't be firing and it's most likely that residual heat in the cylinder walls is providing enough heat to ignite the fuel that's admitted by the carb. - that's why it stops after a second or so as the cylinder walls cool and the fuel stops igniting. It's called dieselling because the engine's running by compression ignition, like a diesel engine…mark1gls said
What do you mean by "dieselling when I turn it off"?
Edit: just popped over to our machine shop and been gifted a 0.8mm MIG welder tip. Is trying it out as obvious as removing the vapour separator, tapping the return feed to M8 and inserting the tip? (after a good clean, naturally!) Would ideally like to get it sorted before I try to drive home as doing such low speeds on the motorway is quite unsafe…!
Stone
Last edit: by Stone
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
Posted
Settled In
Taking the return pipe off the separator, there is a restriction already in the pipe - but the hole in it is huge. Going to try removing it and fitting the MIG tip instead for the drive home…
Stone
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
Posted
Settled In
I realised the MIG tip was too big to tap into the separator (unless I snapped off the outlet and tapped into the hole, but I couldn't see how to take it apart so didn't want to get bits of swarf stuck on the inside…); the old restrictor was just stuck into the pipe so I gave the new one some WD40 and forced it in, then put the pipe back. Changed the air filter while I was there just in case, old one looked alright but the new one has a thicker foam-type seal so might stop the oil a bit better!
Comparison of old with new:
The old one was almost equal in size to the bore of the fuel hose, and it looks like it's stretched slightly over the years so fuel could get all around it as well as through the big hole in the middle. The new one is quite substantial and thoroughly blocking the pipe off so none can get round the edges…and it suddenly feels a lot sportier! Revs much more easily and needed choke for far less time to get it going well. Fingers crossed but it may be sorted, I'll give it a week or so to recur just in case
Thanks for the help!
Stone
"Klaus": 1987 Clipper Cabrio, LA7Y, 1.8 Weber (auto)
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
1995 Corrado VR6, LK4Z: RIP
2003 Golf R32, LB5R
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