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Help translate info in German for carb electro choke

I have '87 E30 BMW with Pierburg 1B2 carb that needs tune-up. I bought Haynes carb manual, Bentley, Haynes and some German E30 manuals, and Pierburg 1B2 manual. I do understand English, but my German is poor.

Can anyone help with translation of a electric schematics of electro choke operation? Or explain to me how it should work? On 1B2 carb choke spring is not heated by coolant, it is only electro heated.

Now I understand that in there are two heating elements in bi-metal housing, and that one is on when the ignition is on. What I do not understand when is other one on. I tested how it works on my car. With cold engine (~5 deg C or ~40 deg F) thermoswitch is open. After couple of minutes it is closed (I do not knew at what temperature), and stays closed at normal engine temperature.

So now both heating elements in bi-metal housing are on. I measured heating elements Resistance, it's ~2-3 ohm.

Now hire is the text that I do not understand, both original in German and my translation (I do not knew if it is correct), along with the link to the drawing:

Die elektrische Verschaltung der Startdeckelbeheizung beim 2B4 Vergaser:

Die Bimetallfeder (1) im Startdeckel (2) wird von zwei Heizelementen (5 und 6) beheizt. Das untere (5) ist bei eingeschalteter Zündung (symbolisiert durch den Schalter 4) in Betrieb. Das obere Heizelement (6) ist von der Stellung des Thermoschalters (3) abhängig. Dieser gibt den Stromweg erst ab 55C frei. Allerdings schaltet er anschließen erst wieder bei 15C ab, so daß die zweite Heizung während der warmen Jahreszeit - wenn die Temperaturen erst gar nicht so weit absinken - häufig gleich vom ersten morgendlichen Motorstart an mitheizt.

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Electrical connecting of the electrical choke for the 2B4 carburetor:

The bi-metal spring (1) in the bi-metal housing (2) is heated by two heating elements (5 and6). The lower heating element (5) is switched on when ignition (symbolized by the switch 4) is on. The upper heating element (6) is controlled by the thermal switch (3). This thermal switch goes open circuit starting from 55 deg C. However it is switched off again at 15 deg C, so that the second heating element (during the warm season - when the temperatures do not drop very low) will be usually on from the first morning engine start.

I do not understand what is suppose tho happen at 15 deg C and what at

55 deg C. Can anybody help please?
Reply to
Yvan
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My interpretation would be that switch 3 goes open circuit when the bi-metal spring temperature goes above 55C, or when the *external* temperature is above 15C - in which case the single heater (5) is sufficient.

Reply to
Albert T Cone

Switch 3 is thermoswitch dipped in coolant. Can it operate like this without any electronic components? It has only two pins, one is +12 V when ignition is on, and other one goes to heating element in bi-metal housing.

Could it be that switch 3 is off below 15C so that choke flap opens slower? Since it is cold it takes loneger to warm up.

I checked today how it works at my BMW. I switched ignition on. After couple of minutes choke flap started to open. I then connected +12V to the other heating element and it started to open faster.

When engine is running, and reached it's operating temperature, both heating elements are on. So it seems that they are on constantly when engine is running at normal operating temperature. Should it be like that. Let me just note that bi-metal spring is not heated by coolant, only by +12V.

Reply to
Yvan

*shudder*

Evil bloody things, those.

Bin it and fit something sensible. Seriously.

Reply to
SteveH

Try

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model search engine is broken ATM it seems, but when it works, you can search for the car and carb model and it will tell you if there is a Weber replacement.

Reply to
NeedforSwede2

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