Author Topic: wideband wont read below 0.86 lambda  (Read 6273 times)

Offline lost

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wideband wont read below 0.86 lambda
« on: May 08, 2016, 08:52:26 am »
I have vems 3.5, and wideband lsu 4.2, it wont read below 0.86 lambda on idle...

If i left it to idle on 0.92 for 10 seconds, it stops reading...

So i cant calibrate injectors, changed big 870cc that had 1.4ms on idle  back to 189cc stock bosch  0 280 150 702

https://youtu.be/A5j-Fg4hmcM

Here is video...

Offline lost

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Re: wideband wont read below 0.86 lambda
« Reply #1 on: May 08, 2016, 03:31:31 pm »
I just recalibrated wideband and ecu nerst /pump, and its still the same, wbo2 wont read richer than 0.9 on idle.....

Offline VEMS

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Re: wideband wont read below 0.86 lambda
« Reply #2 on: May 09, 2016, 04:08:10 pm »
Hello Lost,

If it was working without problems before, its most likely sensor failure; replace it.

Best regards, Dave

Offline lost

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Re: wideband wont read below 0.86 lambda
« Reply #3 on: May 10, 2016, 10:14:07 am »
It can measure 0.7 lambda while driving the car,

While calibrating lsu 4.2 i measured :
88 ohm Rcal on sensor,
145 o2 calibration


and with 100 ohm resistors and led:

4v between pump- and gnd
0v between pump + and - (100 in vemstune)
+450mV nerst and pump - (136 in vemstune)

, do you know if RI target is 165 in vemstune for old LSU 4.2 ? Or i have wrong value here?


Procedure followed : http://www.vems.hu/wiki/index.php?page=GenBoard/Manual/WideBandHardwareTest
« Last Edit: May 10, 2016, 10:34:29 am by lost »

Offline VEMS

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Re: wideband wont read below 0.86 lambda
« Reply #4 on: May 10, 2016, 10:47:39 am »
It can measure 0.7 lambda while driving the car,

While calibrating lsu 4.2 i measured :
88 ohm Rcal on sensor,
145 o2 calibration


and with 100 ohm resistors and led:

4v between pump- and gnd
0v between pump + and - (100 in vemstune)
+450mV nerst and pump - (136 in vemstune)

, do you know if RI target is 165 in vemstune for old LSU 4.2 ? Or i have wrong value here?


Procedure followed : http://www.vems.hu/wiki/index.php?page=GenBoard/Manual/WideBandHardwareTest
Your test values are good, 165 is indeed Ri target for both LSU 4.2 and LSU 4.9, still everything pointing to BAD SENSOR, replace it.

Best regards, Dave

Offline lost

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Re: wideband wont read below 0.86 lambda
« Reply #5 on: August 14, 2016, 03:46:39 pm »
After replacing sensor with LSU 4.9 everything works OK!