difference between fuel sensors questions

[mellow65]

so i have a couple fuel sensor questions i'm hoping someone can help me with.

 

so for the sake of this thread lets just assume that i am swapping a large fuel tank out of a 1st gen legacy and putting in the smaller tank from the impreza or a 2wd tank (not really what's happening, but easier to picture this way )

 

so my big tank has 2 sending units, one on each side of the hump. each sensor measures around 50ohms empty and around 1.5omhs full. these sensors are wired in series so when you measure resistance going to the gauge cluster you get about 90+ohms empty and around 3ohms full.

 

the small tanks and 2wd tanks have one sensor. but according to the service manual the sensors should measure the same ohms.

 

so i guess the question is, does anyone know if there really is a difference between a small tank sending unit and a large tank sending unit. or i wonder if the gauge clusters are just set up to read the different ohms for a pair of sensors rather then just one.

 

so then are 2wd gauge clusters different then awd clusters. but if so why hasn't this been brought up when people do awd swaps.

 

just thoughts im having right now. basically what i'm doing is swapping in a full legacy harness into another car and going to make the fuel pump and sensor work in the other cars gas tank

[nipper]

AWD tanks have a hump in them to allow the drivesahft to operate. The dual sender tanks also have a siphon type pump that transfers fuel from one side of the tank to the other. The Senders are in series. The total resistance is split between the two of them. A 2wd tank does not have this dirveshaft issue so only one sender. The fuel level gauge really does not care what is hooked up in the rear of the car, otherwise people would be specifying (as you pointed it out) a 2wd or awd dash.

 

nipper

 

PS we all know sooby gas gauges are more for decoration anyway

[mellow65]

well sure i know the gas gauge is just a shot in the dark, but it would be better then nothing.

 

but there are 2 different sending units, 2wd and the awd. now i just need to find a 2wd sending unit.