MicroSquirt.com read only forum (Jan.15,2018)

Has anyone been using the Bosch LSU 4.9 WB sensor?

I am trying to get it to work with the JAW controller. I don't know if the LSU 4.2 and the 4.9 can be used interchangeably or not. I assume that they should be able to be interchangeable since they are both WB sensors.

Does anyone have any experience with the LSU 4.9 with JAW or LC-1, or any other controller?

The difference I have found so far between the 4.2 and the 4.9 LSU sensors are that the connector pins are configured differently.


......................................................7 057........................17 025
LSU Wire Colour ....Pin Name.......LSU 4.2 Connector.....LSU 4.9 Connector
Red..........................Ip............................6..............................1
Black........................Vs...........................1..............................6
Yellow...................Vs / Ip........................5..............................2
White........................H-..........................4..............................3
Grey.........................H+..........................3..............................4
none (green)............Rcal.........................2..............................5

Since the JAW unit is based on the LSU 4.2 sensor, the connectors on the PCB are numbered according to the third column shown above. If you have a 4.9 sensor, you need to match up wire colours (not the pin numbers).

I will update this posting when I actually wire up my 4.9 as per the above chart. I am currently wired up like a 4.2, so my connections are incorrect and showing lean all the time.

Someone asked a similar question over on the Innovate Motorsports forums and the LSU 4.9 is not compatible their products, here's the response to that question

Unfortunately not. The LSU4.9 requires different heater drive values and different setpoints for the Sensor impedance

I suspect it's the same with the JAWS unit but see if you can get a hold of Toalan, he should be able to give you a more definitive answer.

With the wiring scheme as described in my earlier post, the 4.9 connected to JAW seems to be communicating well. I now can get varying AFRs at different throttle positions.

My issue is currently with establishing the calibration value of the 4.9. In JAW with a 4.2, the software says to wait for the heater value to be 14-18 when calibrating in free air.

The problem I am having with the 4.9 is that it stabilizes at a heat value of about 23-26. When I calibrate at this number, over and over again, the calibration value changes quite a bit. It should remain relatively the same ( to within 1 - 2 units).