Re: Re: Magnum ignition systems - how do they work?

From: Aaron (acolona@i-55.com)
Date: Thu Feb 10 2000 - 19:37:48 EST


nope, you can spin the cap and the pcm will reset the timing back. More than
the crank position sensor is used. You'd be surprised what these pcm's do. I
watched the code list come up on the computer at a dealership, it measures
just about everything you can think of, battery voltage, coolant temp,
voltage draw, vacuum, etc.etc.

----- Original Message -----
From: Shane Moseley <smoseley@ix.netcom.com>
To: <dakota-truck@buffnet.net>
Sent: Thursday, February 10, 2000 10:51 AM
Subject: DML: Re: Magnum ignition systems - how do they work?

> 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
>
>
>



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