Connect a fuel pressure sensor (or other pressure sensor)

Discussion in 'ecu-GN Frequently Asked Questions' started by EricM, Jul 18, 2018.

  1. EricM

    EricM Administrator Staff Member

    A fuel pressure sensor with a 0-5v output (pretty much all of them) can be connected to the ecu-GN. Don't be confused on the sensor power voltage. Some sensors are powered by 5v, some 12v, but still output a 0-5v signal.

    The sensors have 3 wires: power, ground, and signal. Assuming you have the power and ground squared away, you just need to connect the signal wire to the ECU. One method is to run a wire through the firewall to the ECU, or you can use one of the EGR wires since those won't be used anymore for EGR. The ECU has been designed to use those wires as analog inputs.

    The EGR plug has 4 wires. 12v power, ground, grey, brown. The grey and brown are both analog inputs to the ECU. (pink/black is 12V ignition power, black is ground)

    The Brown wire is "Analog In 1" (which goes to D9 at the ECU)
    The Grey wire is "Analog In 2" (which goes to A4 at the ECU)

    You can connect the fuel pressure sensor signal output to one of those analog inputs. For this example, let use Analog In 1, the brown wire. By the way, Caspers Electronics make a nice kit for this, part 109038 (www.casperselectronics.com) You'll need to tap into the wire, unless you have a connector that fits it.

    Once you've made your wiring connection, we can connect to the ECU with your laptop to set up the input.

    You'll need to set up a Generic Sensor on the Advanced Engine menu. These settings assume you have a typical AEM or SSI 100psi style 5v sensor that outputs .5 to 4.5 volts (0 to 100psi). If you have something different, post here and we can figure it out.

    fuelpressure.png


    The sensor will be called "Sensor 6" or "Fuel Press PSI" in other parts of the software if you want to make a gauge. I set up that sensor in PSI for gauge purposes. If you want to use fuel pressure correction, you will also need a sensor set up in kpa.

    In that case, make another sensor in position 07, still using analog in 1, call it Fuel Press KPA, and use -86 and 776 for the 0v and 5v settings. Sometimes you'll need to bump the 0v setting around a little to make it read zero.

    The ECU will now have fuel pressure as an input, but you'll want to see it on a gauge, so we need to go over making a gauge. I'll make a post about making gauges.
     
  2. Royal-T

    Royal-T Member

    Is it ok to power more than 1 5V sender from the green strip? or do you have to use the additional 22 pin plug?
     
  3. EricM

    EricM Administrator Staff Member

    Yes, you can connect more than one. The sensors use very little power typically.
     
  4. Royal-T

    Royal-T Member

    OK, thanks! kind of what i figured but i wanted to double check
     
  5. Etraugott

    Etraugott Member

    If i want to connect a transmission temp sensor would it be similar to this.
     
  6. EricM

    EricM Administrator Staff Member

    It's similar, but a 2-wire temperature sensor doesn't output a 0-5v signal on its own. You have to feed 5v into the circuit using a resistor (called a pull up resistor). The ecuGN has one input that has a built in pull up resistor for this purpose, which is CAN ADC04. To enable the pull up resistor, you have to open the lid and set a jumper. Then one wire from the temp sensor will connect to CAN ADC04 and the other wire to ground. Then you can can configure the input like a 0-5v input in the generic sensors.
     
  7. Etraugott

    Etraugott Member

    ok, i have a temp sender from my autometer guage already in transmission but its a single wire. the body of sensor is grounded trough case. do you think this sensor would work or do you have a recommended sensor with values already figured out.
     
  8. EricM

    EricM Administrator Staff Member

    You can try it and see. Sometimes there can be ground offsets when doing it that way.
    The SMP TX73 sensor works and is the same calibration as a GM coolant sensor (and is 2-wire).
     
  9. Etraugott

    Etraugott Member

    thanks
     
  10. Etraugott

    Etraugott Member

    Used the TX73 sensor. works great thanks.
     
  11. SpeedRacerX

    SpeedRacerX New Member

    Followed all of the instructions here to install my trans temp sender today as a gauge on the ecu-gn dash. It is a two wire sender. The black went to ground and the white went to adc04 on the ecu-gn. I also changed the jumper on exp-AN4 inside to ON. Seems to work now. I gave it GM calibration. Added the gauge fine. Seems to be reading ok.

    Is there anything I overlooked?
     
  12. EricM

    EricM Administrator Staff Member

    Sounds like you got it.
     

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