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Thread: Having trouble with the USM

  1. #1

    Default Having trouble with the USM

    Hello
    i have the IQ3 dash with the USM Module
    Im trying to connect it to my race car and im having trouble with some sensors
    I have read the "How to" about 10 time regarding this BUT i'm still having issues.
    Im using the USM for Oil T, Water T, Fuel Pressure and 12V event (Brake)
    The 12v event and fuel pressure seem to be working fine but the Temps are giving me trouble
    Im using a 5v Bosch liquid sensor. everytime i connect it to the USM and feed it 5V from the USM it returns 5V back to the dash.
    Ive connected the Bosch 2 wire sensor wires to 5v and signal.
    I know its probably something that i have done but i cant find what it is.
    Can anyone help with this?

  2. #2

    Default Re: Having trouble with the USM

    If it is a two wire temperature sensor you would need to cable it to signal ground on one side, the signal input on the other and then use the pull-up resistor.

    Do you have a sensor part number?

  3. #3

    Default Re: Having trouble with the USM

    Its a Bosch 0280130026

  4. #4

    Default Re: Having trouble with the USM

    That is probably the same sensor as I had in my car (I have actually just replaced the Racepak gear with Motec)

    Connect one side of the sensor to the signal input and the other to the ground input. then go into datalink and start on the config.

    In the appropriate input for the USM, turn on the internal pullup resistor, and then using the datasheet for that sensor, map the sensor resistances against the appropriate temperatures, select "Calculate cal table" and then OK, name the input whatever suits in the pulldown, then send configuration and save the config with a different file name.

  5. #5

    Default Re: Having trouble with the USM

    Thanks heaps for your input
    Ill try this tomorrow and ill let you know how i go.

    Mark

  6. #6

    Default Re: Having trouble with the USM

    Thx Blue
    That worked well for the Water Temp as far as i can see
    Not working too well for the Oil Temp, its the same sender as the Water Temp,
    I have it connected on the side of the Oberg filter in the upper housing, if its getting an air lock would that impede the senders signal?

  7. #7

    Default Re: Having trouble with the USM

    Yeah, it should be the same between the two senders, are they close enough together in the car to swap the wiring around from one sensor to the other, if you do that and the low reading is then on the water not the oil channel then the sensor may be faulty or may not be making contact with the oil.

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