[T3] Thank You for your help!!

Jim Adney jadney at vwtype3.org
Fri Sep 28 06:33:03 PDT 2012


On 28 Sep 2012 at 4:00, miah wrote:

> Well after a few hours of Volkswagen Yoga (Contorting to fit hands and
> wrists into small areas) I discovered three ground wires that have
> been floating in position. This provided the opportunity for my OCD to
> come out and play. So after some time of Clipping, Re-Capping, Shrink
> Wrapping, Labeling, Zip Tying and Tucking main wires¦ this somehow
> remedied the issue. 

Okay, glad that's fixed.

> However after startup and driving around town the "Clicking" under the
> dash still occurs when I press the brake? I´m very curious as to what
> it is that I could´ve missed? 

If this is really a '71, then I'm somewhat puzzled, as I've never 
heard this symptom in those cars. My GUESS is that the click comes 
from the TS relay, and is due to at least one ageing capacitor in 
that relay. The click occurs when your TSs come on and this puts a 
sudden extra draw on the electrical system due to the inrush current 
to the tungsten filaments. The sudden current rush causes a transient 
dip in system voltage, which the TS relay senses and one of the 
contacts in there changes state very temporarily.

I THINK there's a capacitor in there which normally filters out those 
brief transients, but that type of capacitor loses capacitance over 
time and the filtering goes away.

In your '71 the TS relay is a black plugin box in one of the sockets 
above the fuse box. If you unplug it and then try the brakes, that 
should tell you whether it was the culprit. If it is, replacing it 
MIGHT cure the click, but the problem might also be due to excessive 
voltage drop due to a bad connection somewhere in your 12 V supply 
path. 

> By the way, Would a failed MPS cause the hesitation with acceleration
> and wavering Idle? 

No. A failed sensor would stop the car. Please don't try to adjust 
the sensor. Untampered '70-1 MPSs are getting expensive, and attempts 
to "fix" them by readjusting almost always result in failure.

-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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