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RE: [T3] cold start behavior


On 28 Apr 2004 at 14:52, type3@comcast.net wrote:

> What makes me suspect the AAR is not adjusted correctly is that when I had
> it out on the work bench - it was room temp (68ish) and yet the spring
> seemed to be applying pressure to close the valve - not open it.  

The "spring" probably isn't applying force in either direction. It's a 
bimetallic (thermostatic) coil, which just changes the position of the valve 
stem as a function of temp. The central shaft should turn freely in either 
direction. If you release the coil, you should find that the central shaft will 
turn round and round with no real force at any point. It's fairly easy to do 
that and then just put the screw setting the calibration back where you found 
it.

> This seems opposite to what it is supposed to do - open when cold, close when hot. 

Check this in situ by checking whether there is air getting thru it in the hot 
or cold states to vary the RPM.

> I did that hose-pull test...when engine warm I pull off hose to the air
> cleaner and no engine RPM change which is good.  You're right - I still feel
> some suction but not much and plugging the hole to the AAR makes no change. 

Okay, it's working in the hot state. Now do the same test when cold.

> The decel trick did work to clean out the rich cylinders so that is good. 
> Martin at the DDB is going to work on it for me Friday - perhaps I have some
> faulty sensors and/or low voltage from the regulator. 

Could be sensors, or just dull electrodes on your plugs, or just could be the 
idiosyncracies of the FI. 

Do carbed cars ever do this?

BTW, Paul and others, please consider deleting the unused quoted material from 
the bottom of your posts. This saves archive space and bandwidth when you 
consider that it gets resent to hundreds of people around the world.   

thanks!

-- 
Jim Adney
jadney@vwtype3.org
Madison, WI 53711-3054
USA

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