Aaron wrote:
> nope,
Nope what? I would love to spar w/ya on this subject my friend 8-)
> you can spin the cap and the pcm will reset the timing back.
This assumes that spinning the cap will 'set' it somehow - NOT!
> More than
> the crank position sensor is used.
For timing - you are correct - there are LOTS of inputs to the computer that
affect the timing. But they are ALL based on the crank position as a starting
reference. The crank sensor alone would be enough but for driveability and
emissions reasons - other inputs are considered (like rpm, map, vss, etc.)
> 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.
>
Uh Yes. Purchase a scan tool and you can watch them at will. Even log them
w/some models. Right Bernd? 8-)
>
> ----- 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
> >
> >
> >
-- '96 IndyRam w/lots of mods (mine) '96 IndyRam w/lots of options (wifes) - also a numbered (#142) "Track Truck" '74 Triple-Black Dodge Challenger Rallye 360 home-brew EFI R&D vehicle '68 Black Corvette Convertible 427 (For Sale)
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