EFILive question, loop display
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TECH Apprentice
Joined: Jan 2002
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From: Murphy, TX
EFILive question, loop display I haven't had much time for hobby stuff since last fall, but believing life would return to normal at some point I snagged a copy of EFILive V5 Pro. I found some time the other day to familiarize myself with it a little prior to getting back to tuning my 98 C5. I like it a lot so far. Howevere, nothing ever goes quite according to plan... <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />
I noticed that the Bank X status indicators (the little yellow/green cells on the upper left and right of the screen) indicated open loop only at startup, not under WOT/PE conditions. So my first question is whether or not to expect the Fuel System Status PID to indicate open loop at any time other than startup. (I am thinking yes and that I am having a problem going into OL.) Unfortunately, in looking at my old (AutoTap) logs I don't have any scans where I've captured this parameter and been in WOT/PE conditions so I can't really compare to how it used to behave.
My second question has nothing to do with EFILive, but Paul seems like a smart guy and maybe will look here. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> What should the normal response from the rear O2 sensors look like? I used to think it was ideally a phase shifted (really an inverse) diminished amplitude version of the pre cat sensor signal. I don't have a feel for how different a real world signal should look. For some reason I have it in my head that the area under this curve is related to the converter's effectiveness...
My tuning issue is that I'm lean (indicated by WB 02), down on power (indicated by dyno), and mileage is a bit off. No issues bad enough to throw codes and I just passed a TX emissions inspection. Additionally, B2 appears richer than B1. I'm trying to work backwards from the O2 data, verifying that it's valid and go from there. I have some data plots if that's useful. I do have a small sample of old rear O2 data that appears consistent bank to bank. I'm currently seeing a significant variance between banks. <img border="0" alt="[cry]" title="" src="graemlins/gr_cry.gif" />
The service manual states that the rear O2s also contribute to fuel trimming when the signal is well above or below bias voltage for an extended period of time. I haven't heard this mentioned a lot. My third question is whether or not anybody knows how long this "extended interval" is or any more details about the role of the rear O2s in fuel trimming.
TIA!
<img border="0" alt="[USA]" title="" src="graemlins/patriot.gif" />
I noticed that the Bank X status indicators (the little yellow/green cells on the upper left and right of the screen) indicated open loop only at startup, not under WOT/PE conditions. So my first question is whether or not to expect the Fuel System Status PID to indicate open loop at any time other than startup. (I am thinking yes and that I am having a problem going into OL.) Unfortunately, in looking at my old (AutoTap) logs I don't have any scans where I've captured this parameter and been in WOT/PE conditions so I can't really compare to how it used to behave.
My second question has nothing to do with EFILive, but Paul seems like a smart guy and maybe will look here. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> What should the normal response from the rear O2 sensors look like? I used to think it was ideally a phase shifted (really an inverse) diminished amplitude version of the pre cat sensor signal. I don't have a feel for how different a real world signal should look. For some reason I have it in my head that the area under this curve is related to the converter's effectiveness...
My tuning issue is that I'm lean (indicated by WB 02), down on power (indicated by dyno), and mileage is a bit off. No issues bad enough to throw codes and I just passed a TX emissions inspection. Additionally, B2 appears richer than B1. I'm trying to work backwards from the O2 data, verifying that it's valid and go from there. I have some data plots if that's useful. I do have a small sample of old rear O2 data that appears consistent bank to bank. I'm currently seeing a significant variance between banks. <img border="0" alt="[cry]" title="" src="graemlins/gr_cry.gif" />
The service manual states that the rear O2s also contribute to fuel trimming when the signal is well above or below bias voltage for an extended period of time. I haven't heard this mentioned a lot. My third question is whether or not anybody knows how long this "extended interval" is or any more details about the role of the rear O2s in fuel trimming.
TIA!
<img border="0" alt="[USA]" title="" src="graemlins/patriot.gif" />
Re: EFILive question, loop display </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ToplessTexan:
<strong>So my first question is whether or not to expect the Fuel System Status PID to indicate open loop at any time other than startup. (I am thinking yes and that I am having a problem going into OL.)</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The PCM uses open loop prior to O2 sensors reaching operating temperature.
Early PCM's would also enter/exit open loop based on driving conditions such as WOT and decel fuel cutoff.
Some recent PCMs will not enter open loop mode once closed loop has been achieved (unless a fault occurs) regardless of the driving conditions.
I believe this is more of a semantics issue than a fundamental change in the way PCMs operate. Just because the PCM no longer sets a flag to say it is on open loop mode does not mean the PCM is not performing (mostly) the same functions that it would perform in open loop mode. i.e. ignoring the O2 sensor feedback and not updating the fuel trims etc.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ToplessTexan:
<strong>My second question has nothing to do with EFILive, but Paul seems like a smart guy and maybe will look here. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> What should the normal response from the rear O2 sensors look like?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks for the vote <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" /> but I'm a software designer not an EFI tech. I have not taken much time to log/observe the rear O2s. So I won't comment about what you should be looking for and if the data can be used for anything other than cat efficiency.
You mentioned "area under chart" - did you know you can have EFILive calculate integrals and derivatives of charted data? i.e. it can calculate and display/log the slope of the line and/or the area under the line.
Regards
Paul
<strong>So my first question is whether or not to expect the Fuel System Status PID to indicate open loop at any time other than startup. (I am thinking yes and that I am having a problem going into OL.)</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The PCM uses open loop prior to O2 sensors reaching operating temperature.
Early PCM's would also enter/exit open loop based on driving conditions such as WOT and decel fuel cutoff.
Some recent PCMs will not enter open loop mode once closed loop has been achieved (unless a fault occurs) regardless of the driving conditions.
I believe this is more of a semantics issue than a fundamental change in the way PCMs operate. Just because the PCM no longer sets a flag to say it is on open loop mode does not mean the PCM is not performing (mostly) the same functions that it would perform in open loop mode. i.e. ignoring the O2 sensor feedback and not updating the fuel trims etc.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ToplessTexan:
<strong>My second question has nothing to do with EFILive, but Paul seems like a smart guy and maybe will look here. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> What should the normal response from the rear O2 sensors look like?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks for the vote <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" /> but I'm a software designer not an EFI tech. I have not taken much time to log/observe the rear O2s. So I won't comment about what you should be looking for and if the data can be used for anything other than cat efficiency.
You mentioned "area under chart" - did you know you can have EFILive calculate integrals and derivatives of charted data? i.e. it can calculate and display/log the slope of the line and/or the area under the line.
Regards
Paul
Thread Starter
TECH Apprentice
Joined: Jan 2002
Posts: 384
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From: Murphy, TX
Re: EFILive question, loop display Thanks for the response Paul.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by EFIliveV5:
<strong>Early PCM's would also enter/exit open loop based on driving conditions such as WOT and decel fuel cutoff.
Some recent PCMs will not enter open loop mode once closed loop has been achieved (unless a fault occurs) regardless of the driving conditions.
I believe this is more of a semantics issue than a fundamental change in the way PCMs operate. Just because the PCM no longer sets a flag to say it is on open loop mode does not mean the PCM is not performing (mostly) the same functions that it would perform in open loop mode. i.e. ignoring the O2 sensor feedback and not updating the fuel trims etc.
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I can buy that, however I am trying to verify whether or not my 98 PCM should indicate OL or not. If it is, I have a problem which may of course be related to my overall problem. I'd be inclined to think it (really the factory flash, right?) falls into the early category rather than recent.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"><strong>So I won't comment about what you should be looking for and if the data can be used for anything other than cat efficiency.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Well, that's really all I'm after, trying to establish expectations before deciding something doesn't look right.
Failing knowing what the "right" answer is I'm relying on what it used to do. For example, a plot of some old O2 data is here. The troubling new data is here for bank 1 and here for bank 2. Based on variation in data alone, I'm inclined to think something's funky with bank 1. The new data plotted directly from EFILIve is here.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"><strong>You mentioned "area under chart" - did you know you can have EFILive calculate integrals and derivatives of charted data? i.e. it can calculate and display/log the slope of the line and/or the area under the line.
Regards
Paul </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Most excellent. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> I believe I recall reading that somewhere but it hadn't occurred to me. For the current data in the above plots, the integral of B1 data would be much less than the integral of B2 data.
<small>[ April 20, 2003, 04:19 PM: Message edited by: ToplessTexan ]</small>
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by EFIliveV5:
<strong>Early PCM's would also enter/exit open loop based on driving conditions such as WOT and decel fuel cutoff.
Some recent PCMs will not enter open loop mode once closed loop has been achieved (unless a fault occurs) regardless of the driving conditions.
I believe this is more of a semantics issue than a fundamental change in the way PCMs operate. Just because the PCM no longer sets a flag to say it is on open loop mode does not mean the PCM is not performing (mostly) the same functions that it would perform in open loop mode. i.e. ignoring the O2 sensor feedback and not updating the fuel trims etc.
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I can buy that, however I am trying to verify whether or not my 98 PCM should indicate OL or not. If it is, I have a problem which may of course be related to my overall problem. I'd be inclined to think it (really the factory flash, right?) falls into the early category rather than recent.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"><strong>So I won't comment about what you should be looking for and if the data can be used for anything other than cat efficiency.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Well, that's really all I'm after, trying to establish expectations before deciding something doesn't look right.
Failing knowing what the "right" answer is I'm relying on what it used to do. For example, a plot of some old O2 data is here. The troubling new data is here for bank 1 and here for bank 2. Based on variation in data alone, I'm inclined to think something's funky with bank 1. The new data plotted directly from EFILIve is here.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"><strong>You mentioned "area under chart" - did you know you can have EFILive calculate integrals and derivatives of charted data? i.e. it can calculate and display/log the slope of the line and/or the area under the line.
Regards
Paul </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Most excellent. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> I believe I recall reading that somewhere but it hadn't occurred to me. For the current data in the above plots, the integral of B1 data would be much less than the integral of B2 data.
<small>[ April 20, 2003, 04:19 PM: Message edited by: ToplessTexan ]</small>
