Open/closed loop

[Bob Wooten]

thank you gents,

this makes more sense now.  in either case after it has gone into Closed
Loop it can be brought out to goto either PE mode or Hiway Mode.  in either
case it is not in the "normal" operating mode (i guess that would depend on
what you would define normal as, WO is the preferred "normal" but stuck in
traffic is the more common "normal".

i get the PE but is Hiway mode the same in that it reads the O2 sensor but
does not listen to it any more?  or is it similar to PE only it uses the O2
but leans it out instead of fattening it up?

BW



> [Original Message]
> From: Bob Valentine <bob at tecmark.com>
> To: <gmecm at diy-efi.org>
> Date: 12/4/00 4:00:03 PM
> Subject: Re: Open/closed loop
>
> I thought the same thing at first also, not just you confused.  
> 
> The ECM goes closed loop once certain factors are met; min temp, min
> runtime,  02 sensor crossings, mabye a few others I can't remember.
> Going into PE or Highway mode are special-case items that cause open loop
> operation even though the closed-loop entry specs are met and maintained.
>   
> The Int should lock 128, but the BLM will stay wherever it was when you
> went open loop into PE mode.   PE mode is when the ECM is not regulating
> the AFR thru feedback from the 02 sensor.   There's nothing that I know of
> to indicate that you're in "closed but open loop" except the locked
> Integrator.   
>   
> -> Bob Valentine
> -> bob at tecmark.com
> 
> At 10:25 PM 12/3/2000 -0800, you wrote:
> >I used Data master to record the runs & the flag did not go out of
"closed
> >loop".  i did notice that teh integrator (& i think BL) are locked @ 128
&
> >thought how odd.  I am not smart enough to know that this is not "closed
> >loop".  i am assuming that there are some conditions that have to be met
> >for the car to be in closed loop & when one or more of them are not met
any
> >more that it ought to go out of that state.  is there a bit that gets set
> >(or more basically, is there a name for) the period that the "closed
loop"
> >bit is set but the computer is not using the O2 data for determining
> >Injector on time?  is there another Bit that is set (or not set) that
tells
> >you when the computer comes out of closed loop?  this is considered PE
mode
> >is it not, when the CPU is using the additional data in the other tables
> >for additional fuel enrichment?
> >
> >thank you gents.
> >BW
> >
> >I am going to re-read the tuning tips & 101 & see if some more of it will
> >get absorbed.  
> >
> >
> >> [Original Message]
> >> From: Bob Valentine <bob at tecmark.com>
> >> To: <gmecm at diy-efi.org>
> >> Date: 12/3/00 8:45:04 PM
> >> Subject: Re: Open/closed loop
> >>
> >> What makes you say it doesn't go open loop?
> >> 
> >> When mine's (730/$8D) in PE or Highway the scan tool shows "closed
loop",
> >> but closer investigation shows that the Integrator is locked at 128,
which
> >> effectivly is open loop.
> >> 
> >> -> Bob Valentine
> >> -> bob at tecmark.com
> >> 
> >> At 07:59 PM 12/3/2000 -0800, you wrote:
> >> >I just came back from the track today & i am a bit confused.  i
thought
> >> >that when you were past a certain percent TPS (setable via a lookup
> >table)
> >> >that the ecm would go into open loop.  i made 6 WO passes & never once
> >did
> >> >it go into open loop.  
> >> >
> >> >BTW, this is a 7730/$8D ecm.  i don't know what the broadcast code is
i
> >> >have not been able to figure that out yet.  
> >> >
> >> >I am going to analyze the data tomorrow, i am pooped.  it is terrible
> >what
> >> >the sun does to you.  i bet it was 75 Deg in the stands & probably
closer
> >> >to 80-85 on the track.  you gotta hate those Southern Californians.  
> >> >
> >> >thanks Guys, 
> >> >BW
> >> >
> >> >
> >> >--- Bob Wooten
> >> >--- r71chevy at earthlink.net
> >> >--- 71-91 Camaro
> >> >
> >> >
> >>
>
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> >
> >
> >--- Bob Wooten
> >--- r71chevy at earthlink.net
> >--- 71-91 Camaro
> >
> >
>
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--- Bob Wooten
--- r71chevy at earthlink.net
--- 71-91 Camaro


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