Kavlico fuel pressure sending unit

[BlueCH750]

Looking for voltage output as a function of pressure from the sending unit.  How can I correlate the Dynon part number to the Kavlico model?  Then I assume I can find the documentation on the Kavlico site?  Thanks!

Never mind...found the part number on the housing and the appropriate data sheet at Kavlico website.  The P4055 puts out 0.5-4.5 Vdc signal

 

[dynonsupport]

It's not clear why you wanted the output function, but are you aware it is not linear? The function is a curve. Contact us if you need more details.

 

[BlueCH750]

Thanks Dynon, I wanted to know whether or not the output signal was in the mV range or not. The output will be be used for signaling activation of a backup fuel pump in the event of fuel pressure drop or failure of primary fuel pump. I am surprised it is not linear over the operating design range. The Kavlico datasheet did not have any graphs.

 

[dynonsupport]

It is linear if SkyView is not attached. Because SkyView applies a pull-up resistor, this causes some non-linearity (which SkyView happily corrects for).

Make sure your auto backup pump system doesn't load the signal with more than a few K-ohms of resistance or your SkyView reading will be off. Also remember that sharing the sensor wire with another device means either device can mess with the signal if a failure occurs, so it increases the chance of a false reading. Your auto backup pump system may not behave as you expect if SkyView is off, and vice versa.

 

[BlueCH750]

Thanks Dynon...two questions for you then!  Can I somehow measure or "capture" the affect of splicing another signal wire into the the output from the fuel pressure sending unit with any data obtained by the Skyview or EMS.  If you have any experience with the EFII bus manager, that is what I am using to monitor the fuel pressure signal and control activation of a backup pump. Are you aware of anyone else utilizing this in a similar capacity with your products, if so, any issues?

Thanks!  Dave

After talking with the designer of the bus manager this is what I have learned.  "The bus manager has a high impedance input on the sender monitor wire...there is no loading of the circuit"  Thinking it should be OK to splice the wires then feed to the EMS.  Sure would be nice to somehow prove that somehow!

 

[dynonsupport]

Sorry, we don't have any experience with the EFII bus manager.

SkyView will say "fuel pressure low" right in your headset if the fuel pressure does dip, so I think most people rely on that.

 

[BlueCH750]

OK, thanks for the reply Dynon.  I will obtain some ground test measurements with a mechanical gauge to see how closely those fuel pressure values and the Skyview values agree.