O2 sensor oscillations

[Bruce Plecan]

-----Original Message-----
From: mrvette <mrvette at bellsouth.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Friday, October 23, 1998 2:21 AM
Subject: Re: O2 sensor oscillations


>Bruce, from reading the below, it sounds as if you are running one on a
bench,
>not an operational engine, is this correct?

Right

  if it is, than your comments seems
>to make sense, as that is what would happen on a bench...as a dynamic
running
>system on an engine, there would have to be something wrong,

What's the something?.  By using one injector to trigger the O2,
that's the same as the exhaust pulsations off of a 2 barrel TBI,
on a dual plane.  The 55 trims the pulse lenght, and I clip the O2
v.  So what's missing?>
Bruce

 ....GENE
>
>Bruce Plecan wrote:
>>
>> -----Original Message-----
>> From: Greg Hermann <bearbvd at sni.net>
>> To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
>> Date: Thursday, October 22, 1998 9:46 AM
>> Subject: Re: O2 sensor oscillations
>>
>> >>OK, Here's a question:
>> >> I read that, while in closed loop - the voltage on the O2 sensor is
>> >>supposed to cross 0.45 at some particular rate.
>> >>
>> >> Are these crossings producted by "puffs" of exhaust going across, or
is
>> >>the ECU intentionally running lean-rich-lean-rich-lean in order to keep
>> >>the avg mix (over time) "centered" on the ideal?
>> >>Thanks!
>> >>-Bill
>> >>I dunno, but some time with a scope hooked up to look at the frequency
of
>> >>the crossovers vs ignition spark frequency might well begin to give an
>> >>answer--anybody???
>> >Regards, Greg
>> >
>> Running car-no.  Final info.-no.  As things look, right now, on the
>> bench the ecm looks for a +v at a particular time, in ref to a ignition
>> event, as seen by the O2.  TBI, much less picky then TPI.
>>   This O2 feedback to ecm is a pain.  +v is a function of inj PW,
>> and a time delay, from when Int changed.  Maybe the duration of v+
>> will work, but it's a guess for now.
>>   With the 747 I used a 555 on after delay and read off an inj fire
>> signal.  Would kinda go closed loop properly but after time would
>> go open, and wierd IAC BL INT numbers.
>> Bruce
>
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