Lambda Question...

[Simon_16v]

Hey guys,

Trying to do a bit of fault finding on my car with the lambda sensors. I've done a log so have voltages, engine speed and car speed etc.

Should both lambda sensors both be reading the same voltage at the same time? Or how are they meant to behave in working conditions?

Thanks

 

[bloke]

pre cat should 'switch' once engine is up to temp.

 

[Simon_16v]

Once they are both up to temperature, when my car hesitates the precat lambda can read as low as 0.06v and then once hesitation stops it jumps to 0.6v and creeps up with the engine speed. Would you say this is a faulty sensor?

 

[Laine_16v]

You need to log it under steady closed loop conditions, i.e say 4th gear at 30-40mph with light throttle. The sensor output should oscilate regularly between max and min (i guess 0v to 5v), to show that its properly sensing lean and rich conditions with quick response and trimming the fuel output to suit.