Idling Enrichment Valve 021 129 052 A

[Rich]

This is a small valve that is secured to the top of the left-side PDSIT carbuerator, just above the accelerator pump. It operates electronically, and it allows for richer-than-normal fuel mixture during warmup.

Can I operate the carb without it, without the carb leaking or do I have to plug up one or more holes?

Anyone know if a source for jets for the 32/34 PDSIT 2-3 carbs?

Any info appreciated.
Rich
'72 Westy

[Amskeptic]

It is a complicated little mess of orifices and whatnot to deliver the enrichment to that valve and deliver it to the central idling circuit when it decides the engine needs it. Do you not like your enrichment valve anymore? Or did you take it apart to see what's inside and found out that the resistor *was soldered to the spade terminal? I'd leave it on.
Colin

[Rich]

Thanks Colin but my problem is that I have a set of carbs (73) that I intend on putting on my 72, and the left carb doesn't have this piece. It looksd as though it has not had this piece for awhile, and what research I have done indicates that I can run without it, that I simply would not have the benefit of the richer mixture it provides during warm up.

My understanding is that is open when cold and allows more gas to the idle mixture, or that it is closed when cold, restricting air flow and thereby creating a richer mixture. Whichever it is, it reverses position as the engine warms. I am still not positive if I need to plug the hole or holes. I have never seen one of these things.
Thanks again,
Rich
'72 Westy

[rustbus]

again with the old threads...

For some strange reason I'd like to get this idle enrichment thing operational. its a hobby, right?

heres what mine looked like when I rebuilt my carbs....bad angle, but the resistor thing inside felt broken and spun freely.

this thing has come up in a few threads recently and my bus struggles to idle when its coldish out.

is there any repairing this thing? are operational OEM ones still out there or do these things just burn out by now?
_________________
May of '72 Deluxe. 2.0L L-Jet CS & 091 trans conversion
my Bus thread

[sclutty]

Mine did not spin freely, but had 0 ohms resistance, instead of the 65 required. (65 ohms is stamped on the front of the cover).

Couldn't source one locally at a yard, so I'm rebuilding mine. Since it's a bimetallic element, which just needs heat to operate the valve, and it can accept 12v, I figure I can rebuild it with some resistance wire.

OK, so I crushed my existing one and found that's how it was built. Resistance wire wrapped around a porcelain insulator.

I will post more info when I actually receive the wire, ordered from
http://jacobs-online.biz/nichrome_wire.htm

Nichrome 60 Wire (Bare Nickel Chromium Resistance Wire) 40 gauge, Nichrome, Chromel C Wire, Nickel Chromium Resistance Wire 60% nickel, 16% chromium, 24% iron, ASTM B267 and ASTM B344
_________________
'64 Bug
'73 Riviera (small top)
'73 Riviera (penthouse top) -- sold
'75 Super LaGrande -- sold

See my blog or don't

[sclutty]

My rebuild idea worked! Follow along:

Crush the original insulator to see how it was built:

Layout the parts to illustrate the rebuild - the red insulator was my first attempt at building an insulator from heat shrink tubing and JB weld. It worked, but was very difficult to do.

These are the items I used to make the second insulator. Yep, those are lollipop sticks

The lollipop stick proved to be too slick to effectively wrap the wire, so I coated the stick with the latex mold builder. This lets the wire "bite" into something and not slip around.

After I had wrapped enough resistance wire (I decided to use the 40 AWG) to get close to 65 ohms, I coated it in the epoxy. I mixed it and brushed it on with a small model paint brush. Then let it hang.

Here, you can see the wire wrapped around the insulator, under the epoxy.

After putting the enrichment valve back together, I test it by hooking it up to a 12v power supply for < 5 minutes. It opened the little valve, and after a few minutes of being disconnected, the valve shut again.

I'd call it a success.
_________________
'64 Bug
'73 Riviera (small top)
'73 Riviera (penthouse top) -- sold
'75 Super LaGrande -- sold

See my blog or don't

[old DKP driver]

You did an awesome job! isn't it a good feeling to FIX something rather than replace it or forget it.
_________________
V.W.owner since 1967

[rustbus]

My Hero, great work, and with pictures and everything -

While yours is obviously a better route, im going to also trya slightly different rebuild - I called the local electronics supply and they have 12V 65Ohm resistors - if the size is reasonable and fits in the housing, they said it would produce heat....works maybe?
_________________
May of '72 Deluxe. 2.0L L-Jet CS & 091 trans conversion
my Bus thread

[Amskeptic]

Well the funny thing about that enrichment device is that it was a long walk to a short pier.

Because VW was struggling mightily to get HCs and CO down to an acceptable regulations mandate, the carbs were adjusted "too damn lean" for driveability, and that included the central idling circuit. The enrichment box there was to get it running, then get out of the way.

We are now well-beyond such high-wire balancing acts, and you can easily compensate for its lack of participation.

That said, I too had to get mine on the late great Road Warrior to work correctly. I had a simple solder job to do, the resistor itself was fine as were the bimetal and plug, after a half a million miles.
Colin
_________________
www.itinerant-air-cooled.com

[Vanapplebomb]

Were all or just some of the PDSIT 2 carbs equipped with these valves?
_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[Vest Failure]

[Vanapplebomb]

One thing I have found is that the cover doesn't seal well on its own, and needs a little silicone sealer to prevent vacuum leaks. The bimetallic valve controls the air bleed for the central idle system. This air enters the enclosure through a small drilling that connects to a clean air supply via the float bowl. Another source of vacuum leaks is the opening for the screw that attaches the bimetallic strip to the copper radiator enclosing the resistor. If it isn't sealed, put a smear of silicone over it. There are small passages in the central idle circuit easily plugged by dirt that makes its way in from the outside of improperly sealed enclosures.

_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[Tcash]

Vanapplebomb any changes needed?

Thank You
Tcash

[Vanapplebomb]

That is correct. Sorry I didn't bother to lay out the order of the screws. Excellent job with the diagram by the way.

Number 1, 2, and 3 have small insulators benieth the heads. Number 1 is conical, 2 is long, and 3 is short.
_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[Vanapplebomb]

[1500king]

Good fun, ain't it? I've rebuilt quite a few of these. Depending on how I feel, I have used several resistor options, 63 ohm wire wound 3W and also 2W 130 ohm metal film resistors in parallel. The harder part is starting with a valve that can be rebuilt as they often rattle themselves to pieces. The opening temperature spec for the valve is between 0-4 degrees C(Pierburg).

[Tcash]

[Vanapplebomb]

They are adjustable via the threaded brass valve seat. The back side is slotted for use with a large flat head screw driver. Some get pretty stuck with age.
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1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021

[Tcash]

[Vanapplebomb]

Yes, that is correct.

Turn it in (CW) and it will open at a higher temperature. Backing it out (CCW) and it will open at a lower temperature.
_________________
1800 Type 4 Berrien 295

http://www.thesamba.com/vw/forum/viewtopic.php?t=487021