[Diy_efi] northstar DIS and what it all means ?

[Tom Sharpe]

do you have the code?  disassembled and commented? copy please. Tnx Tom.

John Stricker wrote:

> I can't tell you what the engine will do on the fuel side in the event of a
> cam sensor failure, but I'm trying to figure it out on the trouble shooting
> charts.  The cam sensor is used to provide the ICM with cylinder #1 firing
> order information to control the SFI.
>
> As for the dual crank sensors, the crankshaft has a reluctor ring with 24
> evenly spaced notches plus eight additional notches used for synch.  The two
> sensors are spaced so that the signal of the lower one lags the upper by 27°
> of rotation.  The ICM first counts the number of the lower pulses between
> every two upper pulses.  There can be 0,1, or 2 lower pulses between upper
> pulses.  When the ICM sees 0 lower pulses between upper pulses, it starts
> counting lower pulses between upper pulses.  when it counts exactly 4, it
> synchs the ignition on the very next upper pulse.  If the ICM counts over 4,
> it waits for another '0' lower pulse between upper pulses to start counting
> again.  This allows the ignition to synch and fire the fist spark plug
> within 180° of engine revolution.
>
> I suspect the engine will continue to run in a limp home mode, although I'm
> not sure, because the purpose of the dual sensors is to provide quick synch
> and starting and to allow the ICM to maintain ignition synch even if one of
> the three sensors is bad.
>
> If it will help you, I can email the ICM input and output pulse chart to
> you.
>
> Hope this helps.
>
> John Stricker.
> ----- Original Message -----
> From: <Djfreggens at aol.com>
> To: <diy-efi at diy-efi.org>
> Sent: Monday, December 30, 2002 5:32 PM
> Subject: [Diy_efi] northstar DIS and what it all means ?
>
> > i got my hand today on a northstar v8 dis ecm sehcmatic. i was looking at
> it
> > and wondering if the dis doenst see a signal for the cam what does it do
> ??
> > would it go into a limp home mode and fix timing or would it simply go
> into a
> > batch fire mode. also it has 2 crank pickups what for. btw this is for a
> 94
> > system. ive been reasearching this for use with a 727 and $8f code. its
> looks
> > like a good system to pirate if itll work. i would imagine that gm kept
> the
> > dweel control strategy. but as for the 24x siganl. what would you send the
> > ecm the 24x or the 4x and if you disabled the cam would the signal for 24x
> > revert 6x ?? im hoping somebody out there has some answers. guidance and
> help
> > apprciated.
> >
>
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