I'm trying to fit a trip computer to my XT, and I would like to be able to use the "range" function, I know it won't be accurate and I know it's useless, but I still want it and if it's on the computer it must work :-p

 

so, it has a analog dash so it has the wrong sender, but I'm not going to change it because that way the dash gauge won't work.

 

the question is, what do both sensor have as outputs? Can I modify my "analog" sender to give the same signal as the "digital" sender, could it be as simple as 0-10V (analog) instead of 0-5V (PPL signal, digital)?

 

perhaps the FSM's give insight? Anyone care to look in the digi-dash-equipped-cars-FSM?

This is interesering, BUMP, I have the TC and I honestly found that it is accurate, within say 20 miles, Although when the batt has been disconnected it sure does take a long time to re adjust it self.

bump, who wants to check their FSM?

 

I have a XT FSM with the analog dash and it looks like the analog sender unit is of the resistor type and ranges between 7ohm (empty) to 95ohm (full)

There is some discussion about it on pages 2 and 3 of this thread. http://www.ultimatesubaru.org/forum/showthread.php?t=77231&page=3&highlight=Digidash+sending%26quot%3B

 

Some people claim that the units are not that different, and can be intechanged with OK results(gauge indicates off by some)

 

But according to the specs in the FSM, they operate on a diffent principal.

 

Analog dash, the gauge is basically an analog Ohmeter. Uses a very small millivoltage to measure resistance across the sender.

 

Digidash is a higher voltage system. 5v is sent out to the sender and passed through it. The amount of measured return voltage is interpretted, converted to a pulse, and displayed by the digidash. The voltage is varied by a change in resistance in the sender, but the resistance is not whats being measured.

 

My guess is that putting the digidash sender into an analog car, you would just get off readings. The system would work, but since the gauge itself supplies power for it, the voltage would be way too low for the sender to work properly. This means that neither the gauge, nor the RANGE function of the TRIP COMPUTER(all caps like on the car) wouldn't work right.

 

Now putting an analog sender into a digidash car would be bad!! I can't think of why you'd want to, but if you did the voltage would be way to high for what the analog sender was designed for. And it's in the gas tank! That's the last place you want things getting too hot or sparking from electrical problems.

While the method the dashes read the sensors resistance is different, the design on them is the same. I've taken enough electrical engineering courses to know that nothing bad is going to happen from interchanging the two.

 

Both sensors are just simply variable resistors. In fact, there was a person on XT6.net who installed the digital dash into his XT6 and changed out the fuel sender much, much later. He experienced no fires in the gas tank. Only difference, the digidash didn't read the fuel tank level properly (the tach didn't work, but that's an entirely different story).

alright thansk for the info , it looks like it might not be that hard to rig something up to generate a "digidash sender signal" from a analog dash sender

 

no where in the FSM do they mention the resistence of the sender itself? someone care to dive in their car and measure it?

Amperage is what makes things hot, Not voltage.... But the saftey concern is appropriate.

bump, I would like to know this