|Get the spark right
Question : MY 1990 Ford Laser 1.3XL hesitates when accelerating but displays no untoward symptoms
when traveling at a constant
I have had the spark plugs
replaced and the fuel system
checked over by my regular
mechanic who has found nothing
else wrong with the engine.
I would appreciate your opinion
on what else could be causing the
THE symptoms you describe are typically signs of shortcomings in the ignition
The hesitation or lack of power, or even mild jerking are a result of an
inadequate spark intensity at the spark plugs, or an incorrectly timed
Since the spark plugs have recently been changed, you could easily
discount spark plug failure. You could also discount ignition timing
problems for the time being, since this would result in either detonation
(engine knock) or back-firing. The latter is a loud popping noise through
The components that are most likely to fail are the high-tension (HT)
leads and the ignition coil. Ignition leads do not wear in the true sense of
the word, but their insulators will break down over a long period of time;
the HT spark leaks through the vehicle bodywork instead of appearing at the spark plug.
Ignition coils can also fail over a
long period of time. The internal
insulation leaks electrically, resulting
in a weak spark at the plugs. The coil
is an irreparable item and must be
replaced with a new item.
Never mess about with the ignition system unless you are absolutely sure of what you are doing since
there are high voltages that can kill.