Members Page/Eric N/WB Sensor - VEMS wiki www.vems.hu

Started setting up my WBO2, as per the[manual]

Adjusting "pump zero pw" dutycycle

In MegaTune, under settings then under wideband settings, changed the Pump zero pw (wbo2_pump_pw_zero) to try and get pump+ to pump- = appr 0 Volt. I was getting absolutely no change at all, it was originally set at 102 and read 0.4v. I finally realized that after adjusting and saving the value to EEPROM (mcs) ECM reset (eg. BootLoader flash-checksum test, or power down/than up) needed (or trigger or force WBO2 on with mde02 than off with mde00) so the new value actually gets used. Ended up at 101 (0x65) made 0.1v. Type Mcd in terminal program, got wbo2_pump_pw_zero=65. Perfect!
Took me an hour to figure that out, next step will have to wait till another day.
Couldn't wait, on to the next section: (this is also pump testing!)
Readings (with a stolen config.txt) were

Measure the voltage between ground and pump- (pin 5). 3.98v
Measure the voltage between ground and nernst (pin 1). 4.32v
Measure the voltage between nernst (pin1) and pump- (pin 5). 330mV

According to the[manual] that is wrong, so I adjust it. No lcd yet so doing it through MegaTune, kind of a pain actually. Setting the wbo2_nernstdc_target did not do much of anything, and I had to restart my board every time for changes to take effect. Set it to 0x96 and went on to adjust wbo2_pump_pid_ki. I noticed that they did not multiply to 0x4000 so I adjusted wbo2_pump_pid_ki to 7C and now I get

Measure the voltage between ground and pump- (pin 5). 3.98v
Measure the voltage between ground and nernst (pin 1). 4.41v (+/- .02V)
Measure the voltage between nernst (pin1) and pump- (pin 5). 430mV. Actually fluctuates between 420-440 but that's OK

Played with the rest of the settings. This is the final outcome again (I think)\n

ego_conf=06
ego_lag=01
ego_coolant=00
ego_maxtps=FF
ego_maxmap=FF
ego_minrpm=05
ego_maxrpm=3C
ego_warmup=01
ego_lean_limit=40
ego_rich_limit=05
ego_pid_kp=25
mt_unused=00
ego_delta=01
ego_target=19
ego_pid_window=FF
wbo2_warmup_ramp=FF
wbo2_warmup_target=FF
wbo2_abs_limit=F0
wbo2_limit_maxt=FF
wbo2_fallback=80
wbo2_retry_t=06
wbo2_edgetime_corr=BA
wbo2_edgetime_min=50
wbo2_ri_target=96
wbo2_nernstdc_target=99
wbo2_pump_pw_zero=65
wbo2_calibration=BB
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=4E
wbo2_pump_pid_kd=00
wbo2_pump_pid_ilimit=FF
wbo2_ri_confidence_scale=80

It's not a good idea to apply high ego_rich_limit. If there is misfire, the O2 in the exhaust will result in more fuel, which will make the problem worse. Tune richer (with req_fuel, or j[] table), so the ego takes away 5..15% fuel normally. Reasonable to set ego_lean_limit up to 25%, but keep ego_rich_limit low, preferrably max +5..+8%.