PLX Question

[07C6]

Can I hook the NB output from the SM to the harness from the stock 02 sensor, thus sending the ECM a signal, making it think the stock sensor is still in place, or is it more complicated than that. I seem to remember reading somewhere about hooking a couple of 10ohm res in series to simulate the heater also???:shrug Maybe this would be better asked on the PLX forum if there is one.

[KySilverado]

I am doing exactly what you are asking. The analog ouput from the PLX unit runs into the stock wire harness at the original narrow band 02 sensor loaction. I do not use any of the capacitors.

[1BadVTX]

I also wired in my NB through the exising NB plug. Cut the old o2 sensor off then wired the PLX up to the plug. PLX support originally told me to use a 1k ohm resister to emulate the heater but in my case it didn't work. Went with what the instructions said, 20 ohm ( or 2 10 ohm in series) and its been perfect. PLX support seems to believe that it is one or the other depending on the OBD type/application. My service manual gave an o2 sensor operating value of between something like 5-25 ohms as being correct for my o2 sensor so I went with a 20 ohm 10 watt resistor as that value fell within the required range of the stock o2. If you check your manual for your specific NB o2 it should give you the operating ohm's value. That will give you an idea of what resistor to use. Just make sure it is rated for at least 10 watts.

[EC_Tune]

You can also measure the heater ohms (two brown wires on most) and go off that.

[07C6]

On the stock O2 plug (07 LS2 Vette) there are 4 wires. White, Blue and 2 black or dark brown. Is the blue the NB signal, white ground and the 2 dark wires the heater wires? Where did you mount the SM module(little red box) I got the gauge as well, may just make some type of temp mount position for it as a double check to the HPT software. I do not have headers as yet, the stock right side sensor is in the middle of the exhaust manifold between plugs 4 and 6. Did you have to remove the heat shield to get the stock sensor out? Any other pointers in hooking this stuff up? Thanks John

[Dirty Howie]

Are you guys running the PLX sensor in the stock 02 sensor hole or are you putting it in a separate bung.

If you are using the WB in the stock hole is it working well as NB and WB simultaneously????

Thanks,

DH

[EC_Tune]

07C6 -- You do have to remove the heatshield (usually) to remove the stock o2.

The two dark wires in connector Pins D&E are the heater. Put a 10watt 20 ohm resistor across those terminals.

The blue (IIRC) is the NB input to the ECM, and White is signal ground.

DH-- I have been using the PLX as a NB sim for at least a year without any problems. However, I usually run it in OL EVEN while in NB sim mode.

[alanderson1978]

I didn't hook up the NB sim when I put mine in, but I'm tuning on open loop as well. And the voltage of th NB sim is not going to be the same as a real NB sensor. Is there any problem with running open loop all the time? I'll probably have extra bungs put in with the new exhaust. Is there documentation for connecting th NB sim? PLX does not provide one.

[Dirty Howie]

DH-- I have been using the PLX as a NB sim for at least a year without any problems. However, I usually run it in OL while in NB sim mode.

I'm glad to hear its been successful for over a year. I'm a little confused cause I thought the NB was needed in closed loop so I don't really understand what you are trying to tell me

Can you drop me a PM on how much to install this in my Vette ???


DH

[EC_Tune]

If you are adding a bung for the wideband, that is the preferred method. And if so, you don't need the NB sim output.

If you are *replacing* your NB sensor with the wideband and you intend to run closed loop then you *need* the NB sim.

I prefer the additional bung in the collector as it makes everything super simple and can be done by any competent muffler shop (or competent guy with a MIG/TIG welder ). And the stock o2's do their thing in closed loop.

[KySilverado]

I didn't hook up the NB sim when I put mine in, but I'm tuning on open loop as well. And the voltage of th NB sim is not going to be the same as a real NB sensor. Is there any problem with running open loop all the time? I'll probably have extra bungs put in with the new exhaust. Is there documentation for connecting th NB sim? PLX does not provide one.

http://www.plxdevices.com/AppNotes/PLXApp004.pdf

[Dirty Howie]

If you are adding a bung for the wideband, that is the preferred method. And if so, you don't need the NB sim output.

If you are *replacing* your NB sensor with the wideband and you intend to run closed loop then you *need* the NB sim.

I prefer the additional bung in the collector as it makes everything super simple and can be done by any competent muffler shop (or competent guy with a MIG/TIG welder ). And the stock o2's do their thing in closed loop.

The reason I wanted to just replace the NB with the WB is that I thought it would be simpler and less expensive. I have already burned up a few NB sensors and they are $80 each for my 2004 Vette. Also the idea of burning a hole in my expensive Kook headers seems counter intuitive to me


DH

[EC_Tune]

We put in addtional bungs on Kooks all the time. SS welds nicely

[Dirty Howie]

We put in addtional bungs on Kooks all the time. SS welds nicely

Doug

I know you were referring to my LT's and not me personally...right

Anyways, I'm ordering the PLX SM-AFR this morning. I will drop you a PM regarding possible installation for me !!!


DH

[EC_Tune]

ROTFLMAO!

Not a problem. Just let me know...