First off forgive me if this arrives in duplicate - I got pissed off
when my web-based work email system possibly cancelled my last reply to
the list. I have re-subscribed using my home email addy
(smoseley@ix.netcom.com). Ok so on w/the subject at hand...
I would have to agree with V8dakLECC@aol.com on this one - the crank
sensor is the only thing that is required to provide ALL ignition timing
to the magnum motors (V6 & all V8s). The PCM simply switches the ground
circuit on and off inducing current in the high-voltage windings of the
coil. The timing of which is completely controlled by the PCM
(requiring a new program to change ANYTHING). It can do this due to the
resolution that the crank sensor provides - down to a few degrees of
crankshaft rotation. For example suppose the computer is providing X
degrees of timing at 2500rpm. If it decides to advance the timing 5
degrees at 2500rpm - it simply toggles the ground circuit at X-5
degrees. If it decides to retard the timing 5 degrees at 2500rpm - it
simply toggles the ground circuit at X+5 degrees. All in the computer
baby! The distributor does just that - distributes the spark to the
correct cylinder. This is why moving the distributor can have very
detrimental effects - surely you dont want to change the firing order!
This potential mechanical 'error' as well as wasted spark energy are
reasons why the distributor (obsoleted) has been replaced entirely using
direct-fire coil-on-plug setups like on most production vehicles today.
Questions? Send em - I try my best...
Latr,
Shane
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 11:47:59 EDT