Date   : Sun, 21 Nov 2010 17:07:24 +0000
From   : zeem.uk@... (Alex Taylor)
Subject: [OT] Who'da thought...

On 21 November 2010 13:08, Adam Sampson <ats@...> wrote:
> Rick Murray <rick@...> writes:
>
>> If you don't have a choke, you DO have an ECU.
>
> Not necessarily: my MkII Golf has an automatic choke, but the control
> system for it (and the ignition timing) is mechanical, working its way
> through a multi-stage sequence as the engine warms up using
> temperature-sensitive and time-delay valves driven by the engine vacuum.

Many early auto-chokes simply used the coolant flowing through a
bimetallic spring arrangement to operate the choke lever on the
carburettor. Often converted to manual choke with aftermarket kits
because they didn't work very well when they got old.

I've got a 1987 Audi Coup? GT with Bosch K-Jet injection. It's also
got a small box of what I think is analogue electronics controlling
some of it, tucked behind the glovebox. When I got the car the box had
been mostly destroyed by water ingress, and plugging all the various
sensors in would immediately cause the engine to shut off.

Anyone learning to drive nowadays is *very* highly unlikely to see a
choke control. A couple of years ago I lent my dad my 1989 Seat Ibiza
903cc. He gave someone a lift to work on a cold morning and they were
*incredibly* surprised to see him operating the choke knob under the
steering column. It's also got conventional points ignition - pretty
crude even for 1989. It's been sat idle in my dad's garage for a
couple of years now, as it's so 80s looking and boxy that I don't have
the heart to get rid of it.

-- 
Alex Taylor