I am focused mostly on the Maserati.

I did the valve clearance the other winter, I had a new fuel pump, filters, the pressure on the injector was checked, so I was ready to measure the C0% at idle and fine tuning the A/F potentiometer from the Weber injection ECU.

Make Wbo2 is working

My first issue is that I did not get the good O2 percentage for the free air test !

Following advices, I have restarted from the beginning using initial the Wbo2 configuration, megatune miniterminal and the config and upload .bat files.

This is the initial config.

wbo2_warmup_ramp=9C

wbo2_warmup_target=FF

wbo2_abs_limit=E4

wbo2_limit_maxt=A0

wbo2_fallback=60

wbo2_retry_t=06

wbo2_edgetime_corr=00

wbo2_edgetime_min=50

wbo2_ri_target=00

wbo2_nernstdc_target=9C

wbo2_pump_pw_zero=63

wbo2_calibration=AE

wbo2_heater_pid_kp=45

wbo2_heater_pid_ki=11

wbo2_heater_pid_kd=1A

wbo2_heater_pid_ilimit=81

wbo2_pump_pid_kp=15

wbo2_pump_pid_ki=20

wbo2_pump_pid_kd=00

wbo2_pump_pid_ilimit=FF

wbo2_ri_confidence_scale=80.

1) pump_zero test : I get 44.1mV -> good

2) 2x100 ohm test : Pin5-Ground : 3.98V -> good

Pin1-Pin5 : 0.241V -> bad

3) nersnt_dc_target : 9C -> A0

edgetime_corr : 00 -> BA

Pin1-Pin5 : 0.241V -> bad

4) ri_target : 00 -> 96

Pin1-Pin5 : 0.233V -> bad

5) nersnt_dc_target : A0 -> C0

Waiting 32mn or so for an 02 value to display as it is said!!

The trick is that this value may be not displayed, one as to measure a stable dc value at Pin1-Pin5, so I got

Pin1-Pin5 : 0.530V -> bad

and

nersnt_dc_target : C0 -> B0

Pin1-Pin5 : 0.385V -> bad

but Hourrah the set point of the pump control loop can be trimmed!

6) Then it is easy,

pid_illimit = FF (get rid of hard bound),

pid_ki 20 -> FF

as it is asked, there should be a trick in the algorithm since the set point has to be reached whatever the ki value

Pin1-Pin5 : [0.500,0.530]V(instable)

7) Next I lower pid_ki to get a more stable value ?, and I adjust nersnt_dc_target.

I finally got

Pin1-Pin5 : [0.449,0.451](good)

using:

wbo2_warmup_ramp=9C

wbo2_warmup_target=FF

wbo2_abs_limit=E4

wbo2_limit_maxt=A0

wbo2_fallback=60

wbo2_retry_t=06

wbo2_edgetime_corr=BA

wbo2_edgetime_min=50

wbo2_ri_target=96

wbo2_nernstdc_target=9C

wbo2_pump_pw_zero=63

wbo2_calibration=AE

wbo2_heater_pid_kp=45

wbo2_heater_pid_ki=11

wbo2_heater_pid_kd=1A

wbo2_heater_pid_ilimit=81

wbo2_pump_pid_kp=30

wbo2_pump_pid_ki=40

wbo2_pump_pid_kd=00

wbo2_pump_pid_ilimit=FF

wbo2_ri_confidence_scale=80

This is not a fine tuning, since one should adjust in theory the PID parameters with respect to the concerned frequency band so that to prevent noise interference.

9) finally I calibrate for the sensor using : calibration = BA.

Making the measuremen

The workshop manual says that the CO% should be 2%-2.5% at idle. What AFR is that? How to do the measurement?

I put the sensor 10 centimeters inside one of the double tail pipe. I get, for one pipe an AFR value of about 16 (no O2 value), and an O2 value of about 9 on the other (no AFR value), too much air probably !!

The exhaust pipe is new, are the exhaust manifold cracked somewhere (which happens on the Biturbo) or the sensor still catch some air from the end pipe?

Q How deep inside the pipe should be set the wbo2 sensor to give a true value ?

I learned that there is a C02 correction which is made on the AFR analyzer which takes in account the % of CO and oxygen which combines together.

Without that correction my sensor should be set inside pipe as far as possible from the exit. So I made a special tubing with the wb02 which could be insert at the end of the tail type.

PHOTO

I check the AFR ok on the other car, and finally I tune the enrichment very successfully. The car is much more friendly at low speed