1034cc HZ engine with Peirburg 1B3 carb,

Before I removed the inlet manifold – I removed the air filter and took some photos. Since then, I’ve lost the photos and after much studying of the Haynes – I’m very confused about the vacuum hoses and electrical connections.

Usual searches have not found the kind of diagrams I hoped to find…

Please can someone who knows their way around the under-bonnet please give some advice.

VACUUM HOSES;

One hose runs as an 8mm hose from the manifold then steps down to a vacuum size (4mm?) hose and connects to some sort of solenoid on the bulk head (two electrical cables – one is black, the other is black with a yellow stripe). There is another vacuum hose coming from here, does this connect to the DISTRIBUTOR or to the AIR FILTER HOUSING?

There is a vacuum hose connector on the carb at the front of the carb body (car front) – where should this go?

There is a vacuum hose on the back of the carb body – where should this go?

ELECTRICAL.

Should the manifold heater be connected to the RED wire under the MASTER CYLINDER?

There is a heavy(ish) red cable with a 6mm (female) spade coming from the STARTER SOLENOID – where does this one go?

Thanks again – all answers gratefully received – even partial ones. Once I get a couple of connections sorted out, the rest should become simpler.

The lowest connection goes to air filter housing as provides constant vacuum to operate the hot air flap when thermovalve in air filter says warm enough.

The higher connection on front goes to capsule on distributor to provide ignition advance for better economy.

The step down from big tube to 4mm surely goes to bulkhead thingy for idle speed stablisation.

That's from my memory of Sean's carb after he had converted...

Looked in So wird's gemacht by Etzold/

On the bulkhead thingy the top tube goes to the back low part of the carb and bottom tube goes to the stepdown manifold connection.

Edited 30 June, 201511 yr by dvderlm

Thanks dvd,

That sounds like all I need to know....

What is the bulkhead thinngy? is it connecting the vacuum from the inlet manifold to some sort of activator on the back of the carb? What does it do?

Was ist "So wird's gemacht" I've seen the site, can you purchase and download this manual? Looks interesting..

Thanks again

The bulkhead thingy is an 'Idle speed boost 2 way valve.'

Relay 82 controls it when revs drop below 700rpm to keep idle stable and prevent stalls.

See figure 14.4b on page 4A-12 and paragraph 22 on page 4A-15 of Haynes Golf manual.

eg

http://users.net1.cc/pafkata/personal/Scanned/docs%20-%20ebooks/HAYNES%20-%20Data%20Book/VW/1081-04a.pdf

Sean's Weber 32TLM that replaced the 1B3 had a slight idle wander - more modern cars advance ignition to boost idle speed and have a smaller hysteresis. I imagine a heavier crank or flywheel would reduce the wander, but make car sluggish.

Don't know whether you can download it, but I bought a hardcopy of the Etzold book from Germany. It has a multi-page fold out circuit diagram and needs no batteries.

Thanks again DVD.

The book you have, is it this one?

http://www.ebay.co.uk/itm/VW-POLO-2-86C-DERBY-Reparaturanleitung-So-wirds-gemacht-Etzold-Reparatur-Buch-/371239017835?pt=Automobilia_DE&hash=item566f91dd6b

So the 'Idle speed boost 2 way valve.' is connected directly across the coil, when the pulses are over 700/m, it closes the valve? So providing I plug off the vacuum connections, leaving this thing disconnected will cause no more problems than a greater tendancy to stall?

Good info - thanks again.

Yes blocked so there's no vacuum leak. You might find the revs wander from 600 to 800 to 600 every few seconds at idle.

Yes, that's the book.

http://www.amazon.de/gp/offer-listing/3768804089/ref=dp_olp_used?ie=UTF8&condition=used

Thanks DVD.

Not sure if I should order the book new or used at the moment, going to depend on postage for a used one.

I always work from printed material (age thing) but these days I try to buy electronically and print it as this allows me to scribble across it whilst working. You would not beleive me if you saw the state of my laptops though.

Great help - thanks again.

Thanks for all info and help.

Just in case any one (myself including) looks at this thread in the future...

This is the arrangement on my1990 1043 HZ engine with a pierburg 1B carb.

Left,right,front,rear are from the drivers view.

There are two vacuum connections on the back of the carb.

The R/H connection connects to the front most connector on the air filter.

The L/H connection goes to the distributor.

(The other Air filter connection goes to the actuator on the air intake pipe)

There is an adjuster screw (with a large flat head) in a plastic surround - on the front O/S corner low down on the carb. Pointing forwards from there is another vacuum sized connector.

This goes to the L/H connection of the 'Idle speed boost 2 way valve' mounted on the bulkhead.

The R/H connection of the 'Idle speed boost 2 way valve' goes to an adapter allowing it to connect to a 10mm? Pipe stub high up on the inlet manifold.

Thanks everyone for sorting this out.

Where does pipe at bottom of actuator go. Thanks

Air filter inlet warm air flap actuator?

To a source of engine vacuum via a thermo valve in air filter housing.

 

or do you mean the 2 way idle boost valve as pictured here, item 17

https://volkswagen.7zap.com/en/rdw/polo+derby+vento-ind/po/1989-9/1/129-15000/

 

Edited 5 April, 20206 yr by dvderlm