JAW 1.03 Calibration and Accuracy - questions

[skint]

So - I am really getting on well with my 1.03 JAW.  I use the 5V output direct to my ECU and can log the lot - perfect!

But I want to ensure it's very accurate down at 11.5AFR

My calibration currently comes out at either -1 or 0 which seems about right for my low mileage bosch sensor.  Heat sitting at 14.

What I noticed though is that if the battery voltage is a bit lower (car sitting for a while), and heat is 17, I get a calibration of 5.  This is MILES off.

(Note, I am taking the sensor out for true free air!)

So:   Is there a voltage sensitvity here?  Should I do it with the engine running?  (nearly 14V operation).

Any other tips to help me get this as accurate as I can?   

[admin]

Hi,

do not start the engine that will cause noise. If you get swings in the calibration value, just do a number of calibrations and put in the average result.

[skint]

Thanks!   I have now used a balanced 14V supply and re-done the calibration at 16 Heat.   It still comes out at either -1 or 0 so looks good and stable.

It does report (on average) leaner than my narrowband at around the 14.7AFR point.   (thus the initial question actually)

What should win?  Calibration value that matches Narrowband at 14.7 OR true JAW Calibration value?

Maybe my upcoming dyno run will sort me out here!

[skint]

OK - I sorted this:

1) The jaw was a tiny bit out on calibration.  I use -2 instead of -1

2) The V-out from the JAW was not behaving well.... this is where my error in my datalogger was having issues.

I checked and rechecked the v-out from JAW.  I used the default and uploaded the LC-1 mimick as tests.

In the end I made my own calibration and it's spot on now. The values do not match the official V-out table.

I have yet to prove whether this is an issue with the JAW or not - I will get my voltmeter out and measure it all properly but do not assume the V-out is spot on - safer to measure and set it.