Thanks Stefan,

Although this 1982 car doesn't have any electronic ECU, I would bet that
there is some such mechanical compensating control which is probably not
functioning. Unfortunately the rather basic repair manual does not fully
describe such operation or all the aspects of the carburettor. Well, now I
know what to look for. Your information is very logical.

Thank you once again.

Henry

"Razor's Edge" wrote in message
...
Henry,

The ECU will automatically adjust the idle rpm when electrical loads are
connected / disconnected.
This is done by a special idle control valve that its placed near the
throttle on the intake.
They use to have a stepper motor to control the on/off time of this valve
making it kind of PWM.

Regards
Stefan




"Henry Mydlarz" skrev i meddelandet
...
My daughter has an old 1.3 litre engine Ford Laser. The idle speed is
normal
until the headlights are turned on. Then it drops by about 20%. When the
brake lights come on there is a further drop in idle speed, until the
engine
occasionally stalls. Having dabbled in car engine repair and car
electronic
repair I have never come across this. Can this be an alternator problem
where it puts too much load on the engine under heavy current? If so,
what
would it be about the alternator that would cause this? Can it be a
non-electrical problem?

Thanks for any advice.

Henry.