Thanks! I found one in Oz. I'm trying to get approximate shipping sizes figured out.As you can see, it fits snug near the left/right chassis rails and just behind the crossmember near the springs and just in front of the rear most crossmember. It sits just above the spare tyre cross piece (removed in this picture since I have the spare on the rear).
Too cold and dark to go out and measure it on my 80, sorry
What about using the sender from the main tank to determine the fuel level? I am wondering why they put in a separate level sensor for the sub tank system when the main tank already has a fuel level sensor in it?Great question. Theoretically I would think that would work. Just need to be attentive to the level in main tank so you don’t over fill.
Does anyone know what signal is sent from the main tank 75% float switch?
I could make up a circuit that would take the resistance level in from the main tank and at the 1/4 tank level, trigger a continuity signal to the ECU. Pretty simple circuit.From what I recall, the existing sender uses resistance and the ecu is looking for continuity.
I need to do some testing with the factory fuel gage and sensor to see what happens if I tap into that circuit and where it would be best to do that. I need to ensure that I do not cause errors in the main fuel gage reading when the circuit is being referenced. Once I see how that can be done, then it is a pretty simple matter of determining the resistance measurement that corresponds to a 75% full main tank and designing a simple circuit to trigger a solid state switch that would give a continuity signal output that could be used to trigger the OEM system. I do not see any reason why it could not also trigger a relay to run another type of pump. It is just a trigger signal at that point. It would be best if all of this happened in the cab somewhere, as I would not want to design something that lived under the vehicle.@OutlawMike If that type of circuit could be used to shut off a transfer pump like a Holley Blue pump you could most likely market those to members like myself who are running sub tanks without the OEM ECU and transfer pumps set up.
That is the kind of circuit I had in mind to trigger a shut off for a FP relay once the main tank reached 3/4 tank. I was going to include a OEM sub tank switch to turn the pump on.