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Wideband A/F idea - cheap & data logging

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Old 01-28-2004 | 05:15 PM
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Default Wideband A/F idea - cheap & data logging

Innovate Motorsports has the great new reasonably priced setup that uses the Bosch wideband. I see some debate whether these are the same used in a VW that are available for under $50 or whether the one in the kit is a revision that is both more expensive and more accurate. One critique I've seen is the base kit doesn't allow logging anything other than the AF reading.
Even if you buy their stuff to log some other parameters, it still isn't near as complete as standard scan tool software and as important, is in a different file/system from the scan software and it is a pain to splice with scan software data.

How about this idea - if we can get the wideband's sensor voltage into an unused or potentially unused sensor in the PCM, then standard scanner software can log wideband AF voltage with everything else. All we need is a table or formula to convert the voltage and all we need to buy is one Bosch sensor for somewhere between $40-$150. A perfect candidate would seem to be one of the rear O2 sensors- the only problem is that the ECM won't pass the voltage on but some signal it interprets from the voltage. Can anyone think of a sensor that would pass on the voltage and that isn't essential to the PCM? Or at least pass a # that can be easily converted back to voltage? (and then into an AF)

Dean
Old 01-28-2004 | 05:29 PM
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Bosch LSU4 sensors are not electricly compatible with anything on the stock PCM, they require precise heater control. You can buy an Innovate kit and connect it to a rear O2 sensor input on the PCM and log that voltage.
Old 01-28-2004 | 06:30 PM
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You can scale the analog output of the LM-1 to 0v-5v (or other scale) and input that into the PCM for recording.
The basic procedure to do this is on their web site.

John
Old 01-28-2004 | 08:01 PM
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the vw(ag) sensor is $17 wholesale. It's roughly accurate to the low 12's in a/f.

The problem is that its a nernst cell/ion pump. It's a closed loop system. Best way to describe it, is that the amount of current it takes to maintain XX a/f ratio is how the unit determines the a/f ratio present. It's pumping air in through the back of the sensor...

Not quite as easy as it sounds. Most manufacturers (especially bosch motronic) are going to this on the primary sensor, as it allows the ecu to have target air fuel ratios and modify fueling rather fast. I think some GM's use this already
Old 01-28-2004 | 09:01 PM
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Thanks for the replies. So the kit is required in order to 'run' the Bosch sensor. And then it sounds like you take a scaled analog output and get that into the ECM, which it sounds might be easiest through a rear O2 harness. JNorris, did you mean that they actually tell about the part inputting the output signal into the PCM for recording? I don't find that part, which, again, seems like would be easiest through an existing rear O2 connector.. Does anyone know if ls1edit disables rear O2s by side? If not, I might have to duplicate the analog output to both rear O2s. Or maybe it doesn't matter, if the ECM will read and allow logging of the rear O2s with them both 'deleted' in ls1edit, which I'm still not sure if that means that they are deleted or just simply the codes for them being missing is ignored.
Old 01-28-2004 | 10:49 PM
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Originally Posted by Sunset01
Thanks for the replies. So the kit is required in order to 'run' the Bosch sensor. And then it sounds like you take a scaled analog output and get that into the ECM, which it sounds might be easiest through a rear O2 harness. JNorris, did you mean that they actually tell about the part inputting the output signal into the PCM for recording? I don't find that part, which, again, seems like would be easiest through an existing rear O2 connector.. Does anyone know if ls1edit disables rear O2s by side? If not, I might have to duplicate the analog output to both rear O2s. Or maybe it doesn't matter, if the ECM will read and allow logging of the rear O2s with them both 'deleted' in ls1edit, which I'm still not sure if that means that they are deleted or just simply the codes for them being missing is ignored.
Beware that you need to be concerned with the input/output impedances of the PCM and WB unit, as these will affect the voltage seen on the scanner. If they are not matched properly the scanner will show an AFR that is incorrect.
Old 01-29-2004 | 02:05 AM
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Only the codes are disabled, and they can be disabled by side. I have run with my rear O2's connected for over a year but the codes disabled. I can still read them with a scanner.

ChrisB (moderator of this section) has connected the LM1 to the rear O2 input on an LS1. I'm sure he can help you solve any problem you have connecting it like this.




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