Stalling When Coming to Full Stop

[vegpedlr]

My dad gave me an article to read on vacuum gauge diagnosis from Hot Rod mag that got me thinking, even though the examples were all for Holley carbs.

My van sometimes stalls when coming to a full stop after cruising for awhile. The most common place is coming to a stop on a freeway off ramp. All is good while braking until I put the clutch in. Then it can’t settle to it’s correct idle, may bounce around a bit, maybe stall. It might be fine for days, then do it repeatedly on stopping. Always with engine at operating temp.

Any thoughts?
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1985 Tintop 4 sp GW 2.3 “Connie”
2006 Mk V GTI 2.0 FSI “Penelope”

[DanHoug]

try bypassing your Idle Stabilization Valve for a while... just remove the hose from the boot, plug the hole with a cork, cap the now open end of the stabilizer, disconnect electrical plug, and set your idle speed with the large diameter screw staring up at you on the throttle body.

you MIGHT just like not having the stabilizer in the circuit so much you leave it disconnected... like i have!
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[vegpedlr]

[DanHoug]

aw crap... just saw you had a 1.9. my bad. i don't know the 1.9 idle system well enough to advise.
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-dan
60% of what you find on the internet is wrong, including this post.

'87 Westy & '89 Westy both 2.1 4spd

Past projects can be found at--
www.thefixitworkshop.com

[eugenev]

Don't the 1.9's have a deceleration switch? You could have an issue there, old electric switches are temperature sensitive. Maybe warm up the van and then do the trouble shooting from there. Also check the air inlet hose, if the motor is getting into a position that a crack is exposed you can have an intermittent issue like that.

Wanted to bump your post back to the top as I know how frustrating these issues can be.
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1986 Savannah Beige tin top GL 2.1 manual... sold
1990 White Westfalia 1WD

[vegpedlr]

What is this deceleration switch?

It could be the air intake. The PO had some part of it replaced, and the guys at SAH said it still looked a bit wonky. It’s not a big deal, but weird because it’s so erratic, and only when nearing a full stop. Those last few feet I can see the engine struggling to find its idle. Though many times ai don’t notice until I try to turn.
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1985 Tintop 4 sp GW 2.3 “Connie”
2006 Mk V GTI 2.0 FSI “Penelope”

[eugenev]

I didn’t want to go through adding a photo to the gallery so here is a link.

https://images.app.goo.gl/iWixaL1Q6JC3cdov8

If you think about it as the force of the vehicle moves the motor it could expose an air leak in the intake. Then when the van sputters it closes then opens then closes etc. I would check these two things first and they very well could be intermittent.
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1986 Savannah Beige tin top GL 2.1 manual... sold
1990 White Westfalia 1WD

[vegpedlr]

Thanks, studying my Bentley now.
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1985 Tintop 4 sp GW 2.3 “Connie”
2006 Mk V GTI 2.0 FSI “Penelope”