Look at this schematic for my O2 sensors...

[hhosurfer]

I have been working on this for some time and just can not figure this out. It seems the ecu sends a test voltage on the blue wire to the o2 at startup. Most o2 sensors use the blue wire for the sensor signal. But from what I see the voltage on the blue runs 1v to .01volts (normal) but the white also fluctuates the same as the blue.

I added a EFIE device gas went down. Put Resistor on blue wire gas goes down, 15k resistor from white wire to ground gas mileage went up a little. or so it seems.

This does not make sense. So for this drawing what can you tell me about this o2 sensor?

Although the blue and white wires are on the o2 sensor, these colors are for the wiring harness.

Thanks for your help

[GasSavers_BEEF]

this seems to be a repost of the same question but I will try to give some insight to it.....maybe

the lines that say to fuse are probably just hot lines (straight to 12v, probably keyed though so they stay off when the car is off) and then the other side is grounded so I would assume that they are your heaters.

I am not truely sure how an EFIE changes the signal. if you want the voltage to be lower than you could just put a resistor in line (series) with the oxy sensor. I do agree with the other guy(not sure his name) in saying that you may want to do it to all the sensors and not just one.

And I can't tell the colors either. what do the designators mean? reference the schematic when talking about the wires and not the physical color and maybe someone can help you more.

If this helped then great, if it didn't, sorry at least I tried

[hhosurfer]

Yes sorry about the repost. but I did not see any answers...

Yes I did add an EFIE but only the front 2 sensors.

(B) Black (P/W) Pink/White (T/W) Tan/White

The arrow is a variable battery of some sort (o2 sensor)

But what am I looking at? If EFIE drops mileage and adding a resistor in line on hte blue drops the mileage but shorting the white to ground using a resistor increases mileage?

Thanks

[GasSavers_BEEF]

you keep referring to a blue and white wire which I am not seeing on the schematic that you have provided. maybe (and this is just a theory) the oxy sensor is acting as some sort of thermocouple type device which actually outputs a voltage at a given oxygen level.

by putting a resistor in line will reduce this voltage that is being seen which will skew your results one way or another depending on what your ECU is expecting. I haven't done that much with oxy sensors myself so I am not sure about it. I know they work better when they are warm (or hot) thus the heaters.

to clarify better, which sensor bank are you referring to? also the resistor you are shorting to ground, where is the other end of it? at the white wire? are you referring to the striped wires that you mentioned.

I am really not qualified to be answering these questions but I know how it is when you have a question and you feel like no one is willing to help.



*edit* be careful when you change these values because it may make your car run lean or rich. rich burns up gas and lean burns up motors

[hhosurfer]

Here a wiring diagram from Alldata. Now it shows a variable resitor in the O2 sensors like the ATS and CTS (air temp sensor/collant temp sensor)

the photo is a little small so please use this link.
http://www.freewebs.com/hhosurfer//photos/First%20Cell%20Set%20Up/o2sensorwiring.JPG

[bobc455]

I can't see any pictures, they must be blocked by my obnoxious firewall here at work. Could you be looking at the heater circuit for the O2 sensor?

-Bob C.

[GasSavers_RoadWarrior]

Yeah that's wierd, seems to show them as a voltage source, the circled V and a variable resistor. The variable cell symbol is more accurate IMO.