1995 850 GLT O2 Sensor closed loop fault

[misha]

Yes, it is a Bosch universal sensor.
Bosch P/N: 0 258 003 222
As according to Bosch Catalog

According to my o2 sensor catalogue,this numbers are matching with oem o2 sensor.Why did you wrote that it's universal?
It fits to 850 2.0 b5204s '91-'96
2.5 b5254s

[moacyr]

Yes, it is a Bosch universal sensor.
Bosch P/N: 0 258 003 222
As according to Bosch Catalog

According to my o2 sensor catalogue,this numbers are matching with oem o2 sensor.Why did you wrote that it's universal?
It fits to 850 2.0 b5204s '91-'96
2.5 b5254s

Because the connector is different. My older sensor's P/N was 0 258 003 593 (4 pin/1 connector), as the new one had 4 pin/2 connectors. So I cut the wires and used is as universal.

I have already done twice the connections. Problem remaining...

Besides, there is 2 white wires, and I was told by a mechanic that it does not matter the orientation on its connection. Is that correct?

[misha]

The only problem with universal o2 sensors is connector.You can't just solder the wires to old connector.They need to be properly crimped and sealed.Sometimes,universal o2 sensors comes with splice box.
Those two white wires is heater circuit.You can connect them either way.Black is signal and grey is ground.
There was a few complaints about bad oem Bosch o2 sensors right from the box,so there is possibillity that yours was born bad.Bad thing is that you can't return it because you cut off it's connector.

[Ozark Lee]

Besides, there is 2 white wires, and I was told by a mechanic that it does not matter the orientation on its connection. Is that correct?

It is, the white wires are for the heater and it doesn't care about polarity.

...Lee

[moacyr]

The only problem with universal o2 sensors is connector.You can't just solder the wires to old connector.They need to be properly crimped and sealed.Sometimes,universal o2 sensors comes with splice box.

There was a few complaints about bad oem Bosch o2 sensors right from the box,so there is possibillity that yours was born bad.Bad thing is that you can't return it because you cut off it's connector.

The wires were not solded.

There is a possibility, unfortunately...

[misha]

Did you crimped and seal them?I doubt that it had splicing box with it.Splicing box comes with universal ones and not always.

[draser]

Your high positive trim shows engine running lean and ECU adding fuel to compensate. Then there's the sensor question. I'd look at the sensor with the scanner, if it's stuck on low then it's bad. To check that just release some propane in the intake, carb cleaner, etc. If sensor signal goes high then it works. Should be a rapid change low to high.

[moacyr]

Did you crimped and seal them?I doubt that it had splicing box with it.Splicing box comes with universal ones and not always.

At first yes. Then I suspected there could be a connection problem, so I spliced the wires and made direct connection.

[moacyr]

Your high positive trim shows engine running lean and ECU adding fuel to compensate. Then there's the sensor question. I'd look at the sensor with the scanner, if it's stuck on low then it's bad. To check that just release some propane in the intake, carb cleaner, etc. If sensor signal goes high then it works. Should be a rapid change low to high.

I'll try that. I managed to read the trims while driving:

When stepping on the gas, voltage drops to 0V. When pedal released, voltage rises to 0.9V. At this time the loop closes and there is adjustment by STFT. When pressing the pedal again, the loop opens and voltage drops to 0V. Then the STFT locks on 0%.

[misha]

It's because ecu is programmed to totally ignore data from o2 sensors on hard accelerating(full throttle) and to use default values.The reason is that car always have it's maximum power when it needed and there is no risk that ecu will cut off fuel because o2 sensor reads too rich at the moment.

Btw...did you reset codes after o2 sensor replacement?'95 have built in diagnostic tool under the hood.