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Testing an Auxiliary Air Regulator in a 1979 super beetle

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--- Quote from: pittwagen on August 15, 2019, 04:19:44 PM ---Here is one from my spare 2.0 motor taken at 23deg C. an hour ago.  Never messed with, adjusted - nothing.  Did you check the resistance at the plug as per the Bentley.  Should be 30 ohms.  Mine is 30.9.  Best one ever.  Most I have had (probably 10 or so) are in the 40's or 50's. This engine starts right up idles fast and slows down to 900 or so.  Higher fast idle in the cold.  Just as it should.

Maybe you should try one from a FI Rabbit/ early Golf or Jetta.  The don't stay open as long but the initial air flow is similar.  I have looked at them all.  They all fail or work poorly at some point and the rebuilds are junk.

--- End quote ---

Hmmmm.......Pittwagen: so yours in a cooled off state seems to have the almost exact same opening amount as mine in my photo #3.  But yours is from a larger bus engine and I wonder if that is the amount of air that a bus engine uses and a Beetle needs more, possibly?   Although the engine on the bus is significantly larger so that would seem unlikely:  I would almost think it's the other way around and the bus engine needing more air than the beetle engine.   

I had not measured the resistance but I was ignoring that because the purpose of that heating element in there was to close off the airflow through the AAR as the engine warmed up and I was pretty certain that was fine since the engine runs and idles fine when it's warmed up.   But now as I sit here late at night thinking about it, I'm wondering if in fact the resistance/heating of that spring in there is in fact whacked and maybe as soon as I start the engine it's heating up way too much too fast and closing the orifice within a few seconds instead of a few minutes.   That seems possibly hard to believe it might be doing that but I suppose anything is possible.  I will measure that resistance this morning.   Or I can go radical and just pull the electrical connector off and try starting the beetle because then I will know for 100% sure it's not heating up quickly and closing off the airflow.   

Although for fun, I looked up part numbers for the AAR and according to, it seems the same part number 280 140 101 was used for 1975-79 Type 1 and 1976-83 Type 2 so now I'm thinking possibly my AAR is in fact working ok since the opening amount while cooled off is seemingly exactly the same as yours.   Hmmmm....

And..................FIXED!!!!   So thanks to Pittwagen mentioning his "spare 2.0 motor" and my realization that later FI bugs and buses used the exact same AAR in the mid-late 70's and hey, I have a spare bus engine too!  So I went to that spare engine that's been sitting collecting dust, spiders and the odd mud-wasp for the past few years and disconnected and dug out it's oily/greasy/dirty/nasty AAR.   Cleaned it all up, cleaned it out with carb-cleaner and jeez yeah it's opening was just about double the size of the opening of the one I pulled out of my ailing super beetle.  I'd say overall it's about 50% open at room temperature.  The beetle's AAR was around 25%.   Popped it in and tightened up the hose clamps and voila, she started right up and immediately went into that strong purrrr of initial faster idle as she warmed up.  No hesitation.  No chugging slowly and stalling.  Just pure purr.   

Thanks all!

-George, Soo-Jean and Penelope the '79 Super Beetle.


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