[Gmecm] Re: VSS help needed

[Mark Romans]

Actually it won't work without VSS because it's disabled at "X" mph, this 
is in a 730 8D ecm.
Mark
----- Original Message ----- 
From: <DOZIERHC at aol.com>
To: <gmecm at diy-efi.org>
Sent: Thursday, June 07, 2007 1:54 PM
Subject: [Gmecm] Re: VSS help needed


>
>
> Decel fuel cutoff and also enleanment typically would NOT use a VSS 
> input.
>
> Think about it this way.
>
> You have a manual trans (or  automatic with aggressive lockup) and put it 
> in
> a high gear, and decel  from that with the clutch engaged.
> When you get close to idle, you dump the  clutch (or torque converter 
> clutch
> is uncoupled).
> If the decel cutoff worked  off VSS, this would cause a stall due to the 
> low
> speed engine unloading while  the engine was being motored (dry-fired), as
> there is insufficient time to  execute a rewet of the manifold/cylinders 
> to get
> combustion restarted with  efficiency (combustion chambers dry and cold).
>
> So instead, decel fuel  cutoff works as a function of (ECT, RPM, TPS, and
> MAP/MAF).  Additionally,  catalyst heating and O2 heating can also be 
> included
> for optimizing of the  algorithm if necessary.
>
> H. Dozier
>
>
> Date: Wed, 6 Jun 2007 13:20:39 -0500 From: "James Panter"
> <_9jim30 at charter.net_ (mailto:9jim30 at charter.net) >
> Subject: Re: [Gmecm] VSS help needed
> To: <_gmecm at diy-efi.org_ (mailto:gmecm at diy-efi.org) >
> Message-ID: <000b01c7a867$63ee2dc0$6401a8c0 at COMPY>
> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>     reply-type=original
>
> Only other way for decel enleanment is the TPS I guess!  I'm currently
> working with a 7749 and have the VSS hooked up but don't really know if 
> the
> VSS is responsible for enleanment.
> I am also working with a FAST ECM and it requires no VSS signal for it to
> function properly.  Must mean it uses the TPS for the ECM to know what's
> happening.       Jim----- Original Message ----- 
> From: "Cowen" <_captain_krill at yahoo.com_ (mailto:captain_krill at yahoo.com) 
>  >
> To: <_gmecm at diy-efi.org_ (mailto:gmecm at diy-efi.org) >
> Sent: Wednesday, June 06, 2007 12:44 PM
> Subject: RE: [Gmecm] VSS help needed
>
>
> > Just a comment...
> > I don't know for sure if VSS is required for decel fuel enleanment, as I
> > was surprised to find a VSS is NOT required for decel fuel cutoff with a
> > '7730.
> >
>
>
>
>
>
>
>
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