Cruise on 100q

[Huw Powell]

>  > http://www.humanspeakers.com/audi/cruise.htm
>
> Here's a cruise control question: why do the pedals have electrical
> switches and vacuum vent valves? Safety through redundancy?

Speed, as well, I think.  By releasing the vacuum mechanically,
immediately, there is no need to wait for the control pump to let it out
on it's own and the throttle can close ASAP.

> My cruise control system generally checks out okay but it is
> intermittent in use, sometimes not starting and other times cutting out
> while on. I'd like to take the pedal switches out of the loop for
> debugging purposes, if the vacuum vent valves will still serve the same
> purpose.

Why not just measure their resistance when they are supposed to be
closed?  Much safer and every bit as convincing.

My coupe switches were once at about 30 and 60 ohms, and only got there
for a hairswidth of travel.  After cleaning, I got a nice zero or
fraction of an ohm reading, and it was reached solidly over the last
couple of mm of travel.  Worked rock solid after that.  (used to cut out
randomly and on bumps)

--
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/