Stalling & misfiring when warm

[asahartz]

ummm, is this fault new?
im just wondering if the power to the perol cut off solenoid is at fault.

check it is getting 12v when the fault happens, coz its possible it being routed via the them switch for the carb heater (In the end of the metal pipe above the LHS head)

the mainifold for the DG is vastly different, but you need to see if you have Dg heads or Df heads, which will be apparent when you lift the manifold off and see if the inlet ports are the same shape and sizr as you manifold, or bigger, if they are DG?

Definitely getting 12v, as I said I took my power for my strobe off there.

It's a bit irritating to have to lift the manifold just to see if the heads are the right type! Is there not a part number? I can see a number cast into the side of the head.
Getting more confusing by the minute. I know this engine has had a lot of work done on it. For one, the tappet covers carry a Volkspares label stating "manual tappets". The air ducting on top has a label stating "hydraulic tappets"!

[wasserleaker]

just an idea.... but the electrics on a faulty dist. base plate can sometimes play up when hot, causing a worsening misfire and eventually, backfiring and unwillingness to restart until cooled down, i had that prob with mine, and changed loads of ignition parts un-necessarily before finding that it was the baseplate, changed it and the hot misfire was cured.

[asahartz]

just an idea.... but the electrics on a faulty dist. base plate can sometimes play up when hot, causing a worsening misfire and eventually, backfiring and unwillingness to restart until cooled down, i had that prob with mine, and changed loads of ignition parts un-necessarily before finding that it was the baseplate, changed it and the hot misfire was cured.

Well that's a possibility, but I've gone round the engine bay with a can of freezer spray, cooling parts down, and the only bit that makes any difference is the choke pulldown unit on the carb - freeze that and the engine idles better for a few seconds.

Carb is now off being thoroughly cleaned out.

[asahartz]

By jove, I think I may have found it!

What?
If it really is heat and not that the choke has finally come off then re-do WD40 test with something more volatile, like carb cleaner.

I'd run out of carb cleaner, so bought a new can today. After stripping and cleaning the carb again, blowing it all out with compressed air again, reassembling it all very carefully, it started and ran very nicely - for a few minutes. So I started spraying the carb cleaner around the flanges again, and this time there was a distinct difference when I sprayed around the offside head/manifold joint!

So it looks like I need to lift the manifold after all. That will be fun. Is this just gaskets, or something more sinister, like a crack?

Anyone got a proper DG manifold & carb going spare?

[HarryMann]

Good discovery, yes normal gaskets and jointing paste...

If it's a pressed steel one like the 2.1's they can corrode to the point they become porous - so take a good look, maybe a wire brush will reveal something untoward! I suppose a High Temp silicone could fix pinhole leaks in the short term , but it's much more likely to be the gasket/manifold face

[asahartz]

If it's a pressed steel one like the 2.1's they can corrode to the point they become porous

No, it's a cast alloy of some sort. I'll get some gaskets ordered...

[CovKid]

Told you spraying was way to find the leak. These VWs HATE air leaks. It can't idle evenly if theres another source of air. Those who've owned bugs will know that worn throttle flaps did the same thing. I must thank Roger Ball (2 Totlands Drive, Great Clacton) for the many many carbs he rebushed for me using phosphor bronze bushes. He still does carb bushes if anyone is out that way.

[HarryMann]

Cheers Ralph, handy to know someone is still around bushing carbs...

asahartz Keep us informed, as this thread is now a Case History in the Wiki, thanks

[asahartz]

Anyone know where I can source these gaskets on their own without having to buy a full head set?

[HarryMann]

VW parts dept. using the part no. below

[img:800:500]https://club8090.co.uk/wiki/images/InletManifold_1.9.jpg[/img]

[CovKid]

I'm too tight to buy gaskets - always make my own unless its something complex. Even used to make my own carb gaskets and they're fiddly things I can tell you.

Still, these will be metal ones I guess so a visit to GSF or similar may be in order. Just be careful the nuts securing the pipes weren't stripped when first fitted as that may have led to this leak in the first place. Not uncommon - lasts a while then lets air in.

[asahartz]

I'm too tight to buy gaskets - always make my own unless its something complex. Even used to make my own carb gaskets and they're fiddly things I can tell you.

Yes, I made my own carb gasket at the weekend! Scissors and a very sharp knife... I've seen more difficult carb gaskets.

Still, these will be metal ones I guess so a visit to GSF or similar may be in order. Just be careful the nuts securing the pipes weren't stripped when first fitted as that may have led to this leak in the first place. Not uncommon - lasts a while then lets air in.

Nuts? I appear to have bolts... Another thing to investigate then.

Looks like it's going to be the VW dealer as GSF don't even list it for watercooled.

[HarryMann]

Not uncommon - lasts a while then lets air in.

Exactly...

M8 x 50 bolts with a spring washer, shown... suppose one could easily have been horsed up too much and stripped.

Surface plate the flange-ends of the manifolds and deburr the holes lightly with a 1/2" drill by hand - nothing like making sure everything sits flat, regardless of gasket joint. Guessing about 15 lb-ft torque.

Wiki on trueing flat faces

PS. GSF don't list it on the web or you've actually asked them? 2 different things..

[asahartz]

Well I've at last found the time to get this job done. First shock (and warning!) is that I have sourced two of the last four of these gaskets, after which they're obsolete with VW and no-one else has stock

Anyway, next, I stripped the manifold off and just could not believe the cause of my trouble - plain as anything, staring me in the face!

[img:600:450]http://www.b0lus.com/images/cars/vw/IMAG0543.jpg[/img]

That's right, some idiot has fitted the gasket the wrong way round, and you can see in the picture that it was only just making a seal, ever. Worse still, it means the airflow through there was restricted too, reducing power! As if I haven't got enough oddities on this bus already!

So tomorrow I get to put this all back together, and with a bit of luck I'll be back to full running order again!

[ermie571]

Glad you found the cause of your trouble! A nice simple fix hopefully!!

But it may not have been an idiot.....it may have been a learner who made a genuine mistook!!


Em
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