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Author Topic: O2 Sensor Output (mv) compared to measured AFR  (Read 153753 times)

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hogasm

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Re: Re: Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #135 on: July 02, 2013, 07:24:19 PM »

I use a flash light and prebend  the copper tube up to help me.  I know it was always real easy to tell where you were at when using power commander as you could just adjust fuel and see what the readings did.

Looks as if it is that easy, then the dyno operators I have watched are just lazy
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Steve Cole

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #136 on: July 02, 2013, 09:03:50 PM »

I think it is like everything else, once you see someone else do it, it's a lot easier. There are going to be some cases where getting a tube in is tough but it sure doesn't mean you should not do it. Having a long drill bit to reach up through the muffler helps too. I learned that trick from FLTRI
« Last Edit: July 02, 2013, 09:07:06 PM by Steve Cole »
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hrdtail78

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #137 on: July 02, 2013, 09:19:02 PM »

I use blocks of different varieties. As Steve is saying. There are different problems for different ways of doing things.  Different style of blocks even bring up different problem. 

I think a step test might reveal more. Without some of the variance of O2 sampling procedures might induce.
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FLTRI

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #138 on: July 02, 2013, 10:21:33 PM »

 :jack:
you don't think lag comes into play because of the hose length?
I've worked with all the systems and have come full circle back to the dyno sniffer for a few reasons:
* Convenience. I have the opportunity to tune my sniffers for best sample quality...as monitored by watching O2 activity as the sniffer is moved deeper or shallower in the pipe(s) especially @ low rpm/load.

* O2 sensor pressure and temp stability. Mounted in the pump away from the bike pressure remains much more constant than in the pipe where the huge pressure variances alter sensor reading output.

*Accuracy. I have done simultaneous live (power commander) testing with sniffer probes, bung-mounted, and "Herko"-type" blocks in the pipe. They all seem to report fueling changes to me (at the monitor) about the same time.

I know I will take heat for the above statement but I challenge anyone to do the same test and come up with different results.
This is why it works:
Steady state tuning AFR is stabilized before making changes. This can take a couple seconds.
During sweep tuning there will be about a 1/4 sec offset on WOT pulls so that is taken into account when changing VEs.

 Disclaimer: The probe is limited to accessibility, so there are times when another method is used to get good quality sampling.

Bob
PS- As far as the jacked thread...as long as there is something positive to be gained I thinks it's great. :2vrolijk_21:
« Last Edit: July 02, 2013, 10:37:40 PM by FLTRI »
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mayor

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #139 on: July 03, 2013, 06:54:20 AM »

that's good info Jason and Bob. I have the herko blocks now, but I have also considered buying a different style as well. I saw the blocks from the bay area when I was at the vtwin expo, and I did like that set up.   

I have tried to stay away from collecting with the sampling tube while playing on the dyno, but only because my friend's dyno has the old style air pump and I haven't quite figured out how to keep the pipe from moving while the engine is running under full load. We still use that pump, but only to draw air from the herko blocks.  At some point we would like to update that pump, but I would like to hold out to see what DJ has in store in the future.  I'm hoping they come up with an affordable dual channel set up, but that could just be wishful thinking.  One more off topic question for you guys, how are you keeping the sampling pipe from blowing back while running the engine under full load?  I used the sampling pipe on my old RK, but the pipe just wouldn't stay put.     

back on topic:
This premise of this test seems to be whether or not a fixed targeted narrowband o2 sensor data point can be used to determine whether the wide open throttle afr is operating within a safe range.  The test is based on aligning a known collected external reading to the mV readings of the narrow band sensor taken at the same time.  My only concern was whether collecting afr sample with a hose would skew the live data when comparing the collected data from the dyno to the collected data with the narrowbands that are located in the headpipe, since the test is at WOT.  You posted what my concern was, that there can be a lag between the two.  So, will a hose sampled afr reading be close enough for the purpose of this test? 
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FLTRI

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #140 on: July 03, 2013, 11:18:12 AM »

I have tried to stay away from collecting with the sampling tube while playing on the dyno, but only because my friend's dyno has the old style air pump and I haven't quite figured out how to keep the pipe from moving while the engine is running under full load...how are you keeping the sampling pipe from blowing back while running the engine under full load?  I used the sampling pipe on my old RK, but the pipe just wouldn't stay put.
Try using safety wire to lasso the right angle bend you put in the sample tube then anchor it to the bike or the exhaust cooling fan.
... a fixed targeted narrowband o2 sensor...can be used to determine whether the wide open throttle afr is...(added by Bob)> within +/- .5 of a target WOT AFR.
My only concern was whether collecting afr sample with a hose would skew the live data when comparing the collected data from the dyno to the collected data with the narrowbands that are located in the headpipe, since the test is at WOT.  You posted what my concern was, that there can be a lag between the two.  So, will a hose sampled afr reading be close enough for the purpose of this test? 
Sure. See my comments addressing this in my previous post.
Bob
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hogasm

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #141 on: July 03, 2013, 01:30:51 PM »

  You posted what my concern was, that there can be a lag between the two.  So, will a hose sampled afr reading be close enough for the purpose of this test? 

I shortened up your post a little to ask about the lag.....why would one tune a bike using a sniffer or even a narrow band O2 sensor when/if  the bike will be run with wide band O2 sensors. Shouldn't you tune the bike with the components that the bike will be run with :nixweiss: or will the lag be so insignificant that it won't matter

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joe_lyons50023

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Re: Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #142 on: July 03, 2013, 02:16:04 PM »

I recently acquired a wide band commander that I can use with my power vision to view both wideband and narrowband at the same time and my fatbob headpipes don't have horrible locations for the 18mm setup.  I will have to get it hooked up and going.  I know the sample rate won't match the narrow bands but I think it will be fine for the test.
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mayor

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #143 on: July 03, 2013, 02:17:10 PM »

I shortened up your post a little to ask about the lag.....

1. Why would one tune a bike using a sniffer or even a narrow band O2 sensor when/if  the bike will be run with wide band O2 sensors?

2. Shouldn't you tune the bike with the components that the bike will be run with :nixweiss: or will the lag be so insignificant that it won't matter 
I separated your questions into two components.  Before I answer this, please keep in mind that the discussion that we are having right now is to test the validity of using the stock narrow band sensors to dial in the wide open throttle load ranges of the calibration. Your questions are actually closer to general tuning questions, so some of what we are discussing may not make sense since we are talking about doing things well our of the norm.  My answers below may clear up the reason for this discussion though. 

Here’s how I would answer your questions:

1. The stock HD bikes come equipped with narrow band sensors, and because of this the HD closed loop EFI system is only a partial closed loop system.  This system does run a portion of the operating in an open loop mode.  The narrow band systems are the fastest and most accurate in measuring around stoich.  This limits the closed loop control with the factory narrow bands to an area around stoich and with loads around 27~83 kPa MAP (give or take, dependant on the calibration). In laymen’s terms, this will be in your typical cruise areas.  This means that when a heavy load is applied, the system reverts to open loop control.  The open loop fuel pulse width settings are controlled by the settings in the calibration.  The calibrations have an AFR table which tells the ECM what AFR is desired, but that table is only accurate when the VE cells are calibrated to that particular motorcycle.  Since the stock narrow bands are currently limited in use leaner than the typical richer values used to calibrate heavier load open loop cells, broad band sensors are used to calibrate the ve’s in these cells.  If these cells are not calibrated, then the afr can and will be a crap shoot regardless of what the afr table states the desired to be. 

2.  yes, but keep in mind no matter what you do the issues I’ve outlined above still exist.  IMO, the only way to make a closed loop system work is to tune that system with the sensors that you will be using to keep the system in closed loop.  This means that I would not recommend tuning the VE tables with broad bands in the closed loop control able areas.  The reason for this is the data that you wrote into the calibration has the potential of not matching what the sensors are reporting, which could result in a host of other issues.  This does not mean that the open loop section can not be tuned with broad bands.  In fact, as of right now this is the way the majority of people tuning are doing the open loop cells. 

Now with the two above answers, hopefully this thread will make some more sense.  The issue that is in the market right now is most guys that want to tune their bikes themselves (DIY’ers) do not have broad band sampling ability.  What FLTRI (Bob) is proposing is the likelihood of using data that is being reported by the stock system to establish safe limits for wide open throttle.  This isn’t going to change the fact that the fuel control is in open loop, but it really doesn’t matter as long as the engine is operating in a safe range.  What this thread is based on is determining if Bob’s idea has validity, and if so what those safe ranges would be. 
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mayor

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Re: Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #144 on: July 03, 2013, 02:22:07 PM »

I recently acquired a wide band commander that I can use with my power vision to view both wideband and narrowband at the same time and my fatbob headpipes don't have horrible locations for the 18mm setup.  I will have to get it hooked up and going.  I know the sample rate won't match the narrow bands but I think it will be fine for the test.
will be an interesting test for sure.  did you get the AT-110? 
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hrdtail78

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Re: Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #145 on: July 03, 2013, 03:44:30 PM »

I recently acquired a wide band commander that I can use with my power vision to view both wideband and narrowband at the same time and my fatbob headpipes don't have horrible locations for the 18mm setup.  I will have to get it hooked up and going.  I know the sample rate won't match the narrow bands but I think it will be fine for the test.

That's good to go.  I have been reading and checking stock sensors against a couple of broad band set ups I have for sometime.  Amazing what one can see and determine from this info.  Also makes me shake my head when I read how vtune don't work, but...anyway.  Good stuff to have.
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Steve Cole

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #146 on: July 03, 2013, 04:03:33 PM »

One issue that you need to understand when trying to tune with an outside source is that it has no way to align itself with what the ECM is doing. So this becomes and issue when trying to switch between open and closed loop if not done properly. I would assume to be able to use the Broad Band sensor kit with a DJ pv you turn off the narrow band system. If my assumption is right then the stock narrow band system is not being used by the ECM but any of the saved corrections are. So you would need to reset them prior to running this setup to at least put them back to there starting position.
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mayor

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #147 on: July 03, 2013, 04:13:26 PM »

I would assume to be able to use the Broad Band sensor kit with a DJ pv you turn off the narrow band system.
no, they have options for each sensor option individually or both simultaneously.
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Hilly13

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #148 on: July 03, 2013, 05:02:55 PM »

no, they have options for each sensor option individually or both simultaneously.

Even so I think Steve is right about the corrections having to be cleared to get an unaltered result.
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mayor

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Re: O2 Sensor Output (mv) compared to measured AFR
« Reply #149 on: July 03, 2013, 05:12:10 PM »

I think that is a given when using any closed loop set up to auto populate the ve tables.  I read Steve's comments as a one or the other, which is not the case with that system.
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