Misc ?? EFI

[Scot Sealander]

thergen at svn.net wrote:

> I've seen both these conflicting viewpoints expressed before.  To me,
> "closed loop" refers to a control process that is presently using 
> feedback (like an O2 sensor) to maintain some parameter (like AFR).

Exactly.  During PE, the O2 sensor (feedback device) is no longer being
used.  So by definition, it is open loop.

 
> It may be just a question of semantics, but I think it is hindering 
> some  of the discussions.  If we can't all be on the same page, knowing
> what individuals mean by their use of "closed loop" may be good enough.

Tom, you maybe correct.  But I don't think the incorrect use of closed
loop is good enough.  I think those who say it is still in closed loop 
while in PE have never examined any of the control loop code in the 
ECM....

Take this quote:

> While in PE it stays closed loop but it no longer is in learn mode,
> meaning that the BLM and INT values are no longer being modified, 

The integrator is no longer being modified?  How is it then in CL?

I think the culprit is the scanner.  GM never shuts off the closed loop
flag during PE or DFCO.  The only conclusion I can come to is that they
see the CL flag still on, so think the scan tool must be right, 
regardless of the actual operating mode.

Scot Sealander    Sealand at clarityconnect.com