On Sun, 31 Aug 2003 16:12:17 +1000 "Henry Mydlarz"
wrote:

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?

Most modern cars have what is called an "Idle Stabilizer" which is a
valve which tries to respond to changes in the idle speed to help keep
it constant. Adding more electrical draw to the system naturally asks
the alternator to put out more current which will always pull the idle
speed down. This is much more likely to be noticable in a 1.3L engine
than in a 4L engine, which may be what you're more used to.

Try to find the idle stabilizer and see if it is working. As another
poster mentiond, it us usually a PWM type of device.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------