Wide Band without an interface
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TECH Enthusiast
Joined: Mar 2003
Posts: 618
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From: San Diego
Wide Band without an interface Has anyone ever tried to run a wideband through a 0-5v sensor wire (like the AC) and then sending the output to either a guage of some sort or logging the volt reading in a scanner? I was thinking if you just log the 0-5 volt and run the log files into an excel macro to translate it all into true A/F ratio you could do wideband tuning without buying a wideband interface, although granted not real time wideband tuning.
I'm just curious, I saw it mentioned a while back but never saw any feedback.
I'm just curious, I saw it mentioned a while back but never saw any feedback.
Launching!
Joined: Nov 2001
Posts: 254
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From: NC
it was my understanding that the voltage on most wide-band o2's isnt linear, and this makes logging difficult without some circuitry. Sounds like you know how to work around this, and you may be onto something
TECH Enthusiast
Joined: Jul 2003
Posts: 697
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From: Evansville, IN
Actually quite a few people are already doing this. You need a Wideband that will put out a 0-5V signal. Feed it into a 0-5V sensor not being used, like AC pressure and log it with software. Then as mentioned above, use something like Excel to convert to actual A/F readings.
If you're trying to just purchase the sensor itself, with no controller, you won't get very far. The sensor by itself is more or less useless. The controller the sensor plugs into is responsible for controlling the heater, and the pump and nernst cells, which makes the output meaningful. You could wire the heater up but the sensor would still do nothing without proper control of the cells, and sampling of the output.
On The Tree
Joined: Mar 2004
Posts: 121
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From: Cleveland
You will most assuredly need a controller. A W/B without one is useless, as Brains stated. The Innovate LC-1 is your cheapest route. You can program the analog 0-5 volt output anyway you like, and run it into the A/C pressure sensor harness and capture it in your scanner without getting the fancy interface. Observe proper grounding if you expect accurate results.
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Where is the A/C pressure sensor/harness located? I'm very interested in this idea, anybody have any more tips for wiring? With HPT 2.0 you could convert to WB AFR using a custom PID. Also, would having the AC pressure sensor unhooked throw any codes or anything?
Kevin
Kevin
Last edited by LS1PoweredZ28; Nov 2, 2005 at 10:47 PM.
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Verdad Gallardo The sensor is located on the 3/8" dia. line running from the evaporator (firewall) to the condensor (in front of the radiator). Its a 3 wire plug. No I don't know which wire is which 
It will probably throw a code ONLY if you turn on the A/C -- so leave it off while testing
It will probably throw a code ONLY if you turn on the A/C -- so leave it off while testing
so basically u run the LC1 as normal, but plug it into the a/c pressure sensor and then just log that? In what form will the data be collected in and what does it need to be changed to?
The data will be 0-5V. The wideband output is linear, so you would need to find the conversion equation for the LC1 (I don't know if its listed or not), in HPT2.0 you can create a custom PID using the AC pressure sensor and the conversion equation to get the output in AFR. This is what I plan on doing, but I have yet to actually try it, so if I made a mistake in any of my assumptions, someone let me know.
Kevin
Kevin
the lambda sensor itself has a very non-linear output, most controllers translate that on the fly into a linear 0-5v output so it's easy to use. the only WB that i know outputs the signal in a non-linear manner is the Zeitronix one. hptuners forums have an extensive discussion of that from dec of 2004. mapping it from non-linear to linear is pretty easy, especially if you got excel, so i don't really care. the only reason to have it linear if you're feeding it to some generic 0-5v accepting gauge, as they're usually calibrated linearly. either way, the translation has to happen somewhere, unless you got both the output signal and the gauge calibrated in the same fashion.
The 0-5V signal I was talking about was from the WB controller (eventually the PLX M300 in my case). Using that, a HPT custom PID should be able to convert the translated WB output to AFR. ie, create a custom PID with the function: 2*[PID.7101]+10, where [PID.7101] is the AC pressure PID. That should work shouldn't it?
Kevin
Kevin
I'm also planning on hooking up my lc-1 to a sensor input, thinking about using the EGR pintle position input (since my EGR is gone). Someone in an older thread about this said that the sampling rate of the AC sensor is low, so you wouldn't get accurate real-time readings. I've got the EGR connector just hanging out there, would be easy to hook up, just need to figure out which wires (anyone know, or can post the schematic for the EGR?).
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
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From: Lake Zurich, IL
^^^ thing I'd be concerned about there... the stock O2 sensors operate on 0-1 volt... wideband operates on 0-5 volt ... I don't know that the PCM is setup to handle the extra voltage on those pins internally....