Puzzled by emissions.
- talkingcars
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Home to black Alfa Romeo 159 3.2 V6 Q4 ,green MGF VVC and red MG Maestro T16.
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My o2 sensor readings were varying between 0.2v and 0.7v. I’m not sure if those are the correct sort of levels but at least it shows that pscan appears to be able to read variations.
Anybody know what the readings should vary between because I have an exhaust leak (flexi pipe) at the moment?
Robin
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cairnsys wrote: Anybody know what the readings should vary between......
0.8 and 0.2V.
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- sworkscooper
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Bank 2 0.09 to 0.88
I can check what it is when cold (not that it would help ) later .
John
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talkingcars wrote:
cairnsys wrote: Anybody know what the readings should vary between......
0.8 and 0.2V.
Sounds like I’m ok then👍
Robin
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Have you tried a injector cleaner?
If there is no suitable signal from the O2 sensor the ECU put an standard signal in place.
You will see in that case a steady 0.50V on live data. So there is also something wrong with the O2 sensor.
And how is the fuel trim?
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- talkingcars
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I had concluded that the ECU uses the default value of .5v when it doesn't get a proper signal from the Lambda probe.
I suspect the wiring problem is before the ECU relay pack as it has relays related to the fuel pump, purge valve and the lambda probe heater circuit.
Home to black Alfa Romeo 159 3.2 V6 Q4 ,green MGF VVC and red MG Maestro T16.
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You will need an oscilloscope though!
Might be possible to pick up the step changes with an analogue voltmeter though.
You will at least be able to check the supply volts to the lambda sensor and heater, and possibly if it is responding correctly.
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Is it reading what the ECU is telling it, or is it actually reading the Lambda sensor status.
You mentioned, and I am sure I have read elswhere, that iif the lambda sensor does not give a sensible reading, then the ECU takes a "default" value as a "limp mode" to keep engine running.
Is PScan displaying this default value?
What does Pscan display if you remove the sensor?
Seems odd the lambda is a constant voltage. Are you cerain it is not faulty?
Anyway this is outside my experience so cant really be of much help!
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The old sensor was also showed a constant voltage, I have unplugged the lead and it makes no difference.
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