O2 delete question...

[supraguy@aol]

Ok, let me just admit right now that i didn't try to search this subject beforehand:

If i use a wideband O2 gauge's output to simulate the narrowband signal to the ecu, do i need to worry about the heating circuit? I'm wondering if the ecu will throw a code because it's not seeing the proper resistance in the o2 heater circuit. Would this be an issue, or am i giving the factory ecu too much credit in this case?

Thanks in advance.

 

[hvyman]

I don't believe our factory Ecu can handle the wideband sensor input.

 

[The DB]

Some wideband O2 controllers have a lambda output as well.


The DB

 

[jetjock]

Yes although iirc the heater code (21) isn't set on later model years. Otherwise the emulated NB signal should work fine. With earlier years the heater current can be duped with resistance.

 

[supraguy@aol]

Yes, Hvyman/ DB; the wideband unit i am sourcing has a 0-1 volt narrowband output.

Thanks JJ. That's what I was wondering about.
My car/ harness/ ecu is 1988. I was planning to splice the narrowband output into the signal pin of an original oem O2 connector, to keep wiring neat. Should I bridge the two heater element wires with a resistor, and if so, what rating should it be?
I'm unfamiliar with how much current normally passes through this circuit.

 

[jdmfreak]

When I installed a wideband on my 88 I used the narrow band signal it works fine I clipped the sensor wire to the stock sensor and left it (the old o2 sensor) zip tied in my engine bay still connected to the heater wires to avoid the code until I found out what resistor to use however on a unrelated issue I blew the engine before I found out

 

[jetjock]

Iirc about 1.5 to 1 amps depending on if it's the older or newer, shorter, O2 sensors. There's a thread on it somewhere. 1 amp should be plenty to make the ECU happy. Use around 15 ohms @ 20 watts. Wirewound or film. Allied or Newark et al has them. Screw the small packaged film one to something for sinking. The other option is to do what jdm suggested and simply leave the old heater connected.

 

[supraguy@aol]

Yeah, sounds alot easier if i just leave an O2 sensor in situ, and just hijack the signal input.
OR... Just not use the narrowband feature of the wideband unit at all, i suppose...

 

[jetjock]

Well, you seemed bent on using the WB but my recommendation has always been to stick with the NB for feedback. Contrary to popular belief it's more accurate.

 

[Dan_Gyoba]

I did some research after asking the same question here.

The primary thing "wrong" with the wideband simulated output is response speed. The upshot of what I found was that the majority of users should be fine with it, but occasionally it can cause problems because it doesn't react fast enough.

I'm leaving the stock sensor in place, and am setting up a switch so that I can use the simulated output from my wideband as well.

 

[Nick M]

Yes, Hvyman/ DB; the wideband unit i am sourcing has a 0-1 volt narrowband output.

In addition to the wideband? The Toyota "wideband" that they call the air/fuel ratio sensor operates at a much higher heat range than a standard oxygen sensor. I don't know why yours would not be the same way.

 

[jetjock]

His does Nick but what he's referring to is the sensor controller's ability to emulate a signal that can be substituted for the stock NB. That way he can get wide-range display with narrow-band control. It works but I've never been a fan of the arraignment. Must be all those years as an automation guy...

 

[supraguy@aol]

Sounds like a new stock unit is going in...