I have just purchased and fitted a dawes AFR meter. It only has four lights and concentrates on the top end of the voltage range from the lambda sensor.
The instructions quote that outputs of around 0.92-0.94 volts are indicative of the best AFR.

But now I have read something lese that says that the lambda sensors output around 0.5 volts to 0.7 volts at the optimum AFR.

Which is the correct info???

Based on the dawes info my car is running lean, based on the other info, it's running fine.

 

Both are right - the first on full load, the second on cruise/idle.

I would find 0.90 or more generally acceptable, although many standard cars will run 0.92 to 0.94.

With heavy mods you need to confirm with a wideband though.

 

Thanks for that. It seems that during WOT my car is running less than 0.90v. Is this something to worry about?

infact I can never get it to read above 0.9v.

 

mines normally on .895mv (full boost 4/5 gear)according to my scooby monitor, until it warms up and then reads less

you do relise that they genrally read lean when they get hot, the hoter they get the leaner they tend to read

Bob Rawle told me this way to do a test, which was to cruise about for a while to get it "coolish", then select 4th gear and power through to the redline and monitor the readings.
try that and you might get diffrent readings (if you just hammer your car all the time you probably wont be getting a correct reading)

 

Not necessarily a problem, but what is your model and mods? Any mods to inlet tract?

 

It's a 94WRX with scoobyecu, downpipe, standard induction.

I have read recently that the max voltage output signal from the bosch sensor is 0.9v so that would explaing why I never read above 0.9v.

 

slight hi-jack sorry

John, Im interested in getting a WB but so far the cost has been prohibitive, any suggestions?

 

Got it explained now:

The WRX dawes meter reads up to 0.9v:

http://www.dawesdevices.com/wrxmeter.html

The normal dawes meter reads up to 1v:

http://www.dawesdevices.com/airfuelmeter.html

I bought the wrong one!!!!!

Make sure you don't

 

I realise I am talkin gto myself here but just incase someonw does what I did and gets the wrong Dawes AFR meter, I found if you open it up there are two trim pots to adjust the voltage reading values, so it's easy to sort out.