Home build genboard 3.8b, SN: 11034
While driving, ignition misfires suddenly occurred from 5500 rpm when the boost pressure is reached, the lambda value went to 0.65.
I then checked the lambda calibration and it was out of range. Previously I had the calibration value of 161 and now I had to set it to 208 to get to 20.9%. Now I'm not sure whether my lambda control is working properly. To test this, I measured all the values.
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Bosch LSU 4.9 sensor
GND to Pump- : 4,04V
Pump+ to Pump- : 0,611V (lower than nernst to pump- voltage => weird)
Nernst to Pump- : 0.939V
- nernst and pump- is normally around 0.45V.
- When we use 100 Ohm resistor between nersnt and pump- and 100 Ohm resistor between pump+ and nernst, usually 0.9V is measured between pump+ and pump- ...
- Please confirm that pump+ to pump- is lower than nernst to pump- (This sounds weird). Maybe add measurements relative to ground, just in case (verification). Are you certain about these measurements? Perhaps the sensor failed in some unusual way?
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I try to adjust Pump-pw-zero and wbo2_nernst_dc_target, i changed the values in vemstune, but on the multimeter nothing changed.
The sensor heating works proberly.
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wbo2_abs_limit=E0
wbo2_limit_maxt=F0
wbo2_fallback=71
wbo2_retry_t=06
wbo2_ri_target=B4
wbo2_nernstdc_target=86
wbo2_pump_pw_zero=67
wbo2_calibration=C2
wbo2_heater_pid_kp=45
wbo2_heater_pid_ki=11
wbo2_heater_pid_kd=1A
wbo2_heater_pid_ilimit=80
wbo2_pump_pid_kp=15
wbo2_pump_pid_ki=4E
wbo2_pump_pid_kd=00
wbo2_pump_pid_ilimit=FF
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I think the problem was triggered by a defective fuel pump relay and interrupted the flyback while driving. Is it possible that the two ICs U7 and/or U17 (LM324) have been damaged?
- LM324 or LM2902 has never ever been damaged in our experience (>10 thousand units), it is protected by resistors and rather sturdy IC (withstands 32V supply).
- However it cannot be ruled out, and it is very cheap. If you order anything else from WebShop, write in this URL into order comment and "Please add an LM2902D SOIC14 quad-operational amplifier IC free of charge, thank you".
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