I should probably know this already, having owned this car for 5 years now,
so feel free to flame. I’ve got an ’87 Stanza, with the CA20E engine. This
engine has twin-spark ignition (i.e., eight plugs and a distributor with
eight points). How exactly does this work? Does it switch between sets,
say at a certain RPM? Or does it fire both sets all the time, maybe to
ensure complete combustion? They definitely don’t fire at the same time,
judging from the pattern of the points; one set seems to be 45 degrees out
ahead of (or behind?) the other. Just wondering, really.
Thanks,
—
Mike Smith. No, the other one.
On Tue, 3 Nov 1998 14:31:19 -0500, "Mike Smith"
<kld_msm…@NOSPAMearthlink.net> wrote:
>I should probably know this already, having owned this car for 5 years now,
>so feel free to flame. I’ve got an ’87 Stanza, with the CA20E engine. This
>engine has twin-spark ignition (i.e., eight plugs and a distributor with
>eight points). How exactly does this work? Does it switch between sets,
>say at a certain RPM? Or does it fire both sets all the time, maybe to
>ensure complete combustion? They definitely don’t fire at the same time,
>judging from the pattern of the points; one set seems to be 45 degrees out
>ahead of (or behind?) the other. Just wondering, really.
>Thanks,
>–
>Mike Smith. No, the other one.
The 2 plugs per cylinder design is to allow the the ignition system to
switch from the normal 2 plug to 1 plug ignition during heavy load
driving conditions in order to reduce engine noise. The system also
functions to advance timing by a specified amount during 1 plug
operation. The switching is done by the ICU (ignition control unit)
signals to the distributor in response to signals from the ECU (engine
control unit). it changes to 1 plug operation whilst the engine is
under heavy load and the engine temp is above 59degF. The input
devices used are the air flow meter, throttle valve switch and engine
temp sensor.
Trapper