747 VSS Question

[Bruce Plecan]

A G20 is a large van, yes?.
Bob on that van was there a speedo cable?.
If with a speedo cable then was there an inline magnetic vss sensor?.
Now ya got me curious.
Geesh, this is maybe related to what the cruise?.
Bruce


>
> The optical buffers I've seen are lime-green in color. They have
> a three wire cable to the optical head. The edge card conn has
> two sets of outputs, one for the ecm, the other for cruise.
>
> Recently I grabbed a '747 out of a van that had a small black
> box attached to the ecm mount. At first I thought it was a drac.
> However, no jumpers and not too much inside. Now I'm thinking
> it was maybe a magnetic buffer. Next time I run into one at the
> yard, I'll check more closely for the pickup. An inline mag unit
> that goes to this buffer would be handy.
>
> And yes, I've kinda' wondered about that magnet generator
> shown on the prints.
>
> BobR.
>
> Bob Valentine wrote:
>
> > No ABS on the van, front or rear.   If it makes a difference this was a
> > factory TH400 van.
> >
> > I'm going to open up the VSS buffer tomorrow and see if there's
something
> > like a unused set of inputs for a mag sensor.
> >
> > -> Bob Valentine
> > -> bob at tecmark.com
> >
> > At 07:19 PM 12/15/2000 -0500, you wrote:
> > >
> > >
> > >Sounds like the G20 had maybe some version of ABS??.
> > >For those they need a high resolution VSS, so yes there would be a DRAC
of
> > >some fashion.   This is all off the top, of my head seen I've never
actually
> > >seen what you have there.
> > >bruce
> > >
> > >
> > >
> > >> On a '88 G20 van I just ripped apart the VSS is optical and goes to
the
> > >VSS
> > >> buffer, which is what I expected.  Saved cluster and buffer just in
case
> > >> needed.
> > >> From the '747 diagrams posted on /incoming (specifcally 747ecm5.jpg)
it
> > >> shows a "permanant magnet generator"  hooked to the VSS buffer and
then to
> > >> the ECM.   I thought '747 trucks used optical VSS?
> > >> Is there a different VSS Buffer for magnetic and optical?  Is there
such a
> > >> thing as a '747 truck w/ a mag. VSS?
> > >> I looked in the archives and there's a ton of info about the later
DRAC's,
> > >> and about eliminating the pass. car VSS buffers for TBI -> '730
convert.
> > >> I'm putting a '747 TBI on a '84 GMC pickup.     Might be able to put
the
> > >> 88' G20 van speedo guts in the '84 GMC pickup cluster if I need to,
last
> > >> resort.
> > >> -> Bob Valentine
> > >> -> bob at tecmark.com
> > >
>
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