Wideband guage...

EmersonS70t5m · Post by **EmersonS70t5m** » 18 Apr 2019, 15:11

So, trying to install a wideband sensor, and I dont know what wire to spice to the 5 wire Bosch 02 sensor I have. The guage has one sensor wire off the back. I've tryed a few different wires but still cant seem to figure it out.

Post by **RickHaleParker** » 18 Apr 2019, 17:43

Five wires? ..... Sounds like your tapping the wrong sensor. O2 sensors are four wires. Two for the heater, two for the sensor.

Post by **bmdubya1198** » 18 Apr 2019, 21:13

The upstream O2 sensor on the Motronic 7 cars has 5 wires. I believe M4.4 and older sensors have 4 wires.

From what I've read, you can't use the stock "wideband" Bosch O2 sensor with an AFR gauge. I don't know exactly what the issue with it is, but I think it has something to do with the type of wideband gauge that it is. It's designed to communicate with the ECU, but not give specific readings that would be useful for air to fuel ratio info.
Do a Google site search on Volvospeed. There are a few threads over there that talk about this.

Post by **RickHaleParker** » 18 Apr 2019, 22:00

ME7 emissions for 2000 S70. I could not find emissions in the 1999 EWD.
Next question is: Which wire does he need to connect his black wire to?
7/15 and 7/82 are the O2 sensors.

Post by **abscate** » 19 Apr 2019, 05:09

You might find the outputs tabulated on the Bosch site if you scour the webs

It looks like the O2 sensor output I still com8ng over A41 and A42

Post by **bmdubya1198** » 19 Apr 2019, 07:40

From what I've read you need to tap into the black wire. I'm assuming the one coming from the O2 sensor and eventually leading to A41.

Post by **abscate** » 19 Apr 2019, 09:14

I completely messed you up. I think the upstream OXS is a wideband which does not toggle between 0.5V, so that post is internet fake news.

SCope traces for a wideband are probably on the picoscope website

Post by **abscate** » 19 Apr 2019, 09:25

RickHaleParker wrote: ↑18 Apr 2019, 17:43 Five wires? ..... Sounds like your tapping the wrong sensor. O2 sensors are four wires. Two for the heater, two for the sensor.

ME7 five wire OXS for the upstream one..Bosch 15667

Yellow is OXS Ground
Black is OXS signal

Post by **RickHaleParker** » 19 Apr 2019, 09:51

To figure this out we would need to know what Wideband Guage he is installing and find the instructions for it.

Post by **bmdubya1198** » 19 Apr 2019, 11:06

If he's using an aftermarket wide band O2S with a gauge, you can't use that in place of the stock upstream O2S. ME7 certainly won't like that.

The correct way to do this would be to weld a new bung into the downpipe to use the wide band sensor.