[T3] ? on dist drive

[Jim Adney]

On 16 Aug 2016 at 16:06, William J wrote:

> I've also been trying to find any info on just 
> what pin 14 on a late E FI system ECU does.

Pin 14 on '72-3 cars, E brains, controls full load enrichment.

On '68-9 cars, A & B brains, this function was done by the pressure 
switch.

On '70-1 cars, C & D brains, the pressure switch was eliminated and 
this function was taken over by the new diaphram in the C pressure 
sensor.

In '72, the diaphram was eliminated and the function was taken over 
by the TVS, on pin 14.

While the functions were the same, the various brains probably dealt 
with this differently.

Note that the instructions in the Bentley for adjusting the TVS are 
correct ONLY for '68-9. Correct adjustment of the later, 4 and 5 pin 
TVSs requires either the Bosch tester or an Ohmmeter. Late 
replacement TVSs, however have an internal stop that makes manual 
adjustment possible, without instruments, but the only way to know if 
you have one of those is to open it up and look. Then you have to 
know what to look for.

I have a writeup on how to adjust each generation of the TVSs. Email 
me if you want a copy.


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