ic7/ avi fuel tank input

[Black240ct]

how's it going.

working with the IC7 inputs i wired in the fuel level sensor from my 1997 nissan 240sx.

The nissan wiring has Ohm reading from a ground wire through the sensor is 4-6 ohms at full tank and 80-84 ohms at empty..

now on the IC7 configuration for fuel level off the AVI4 90-0 ohm. but the calibration table is a percentage to volts.

having trouble setting this appropriately.

before converting the cluster from OEM i had about 3/4 tank..
while setting up the fuel sensor in IC7, the gauge read 72%... happy with that result.
But i save the data/ sent to dash... then turn car off and back on and the display is reading 50%.


not sure if i am missing something, not having luck with web searching or tech articles.


also what is the purpose of the pull up resistor


appreciate any assistance.

[JimKden]

Here is a generic spreadsheet to calculate the Volts for resistance using the 1K resister pullup resistorthat Haltech uses. Where the Haltech input has no pullup resistor the user needs to provide the pullup.

[Pirana]

I have an evo 9.... the problem is what voltage is the fuel sender using as reference 5v or 12v? That table utilizes a 5v reference. If we know the reference voltage then it's easy to calculate output voltage for the table.

[ImiTek]

You can select raw voltage in the drop-down list to get voltage
https://youtu.be/hF2PjWJBxo8

[Pirana]

I did figure out now about the RAW voltage, the problem I have now is that the voltage fluctuates too much and I can't figure out what is reading! If I empty the tank I get fluctuation from .19v to .30v.... the voltage does change when the full tank is full to about .45v but again... can't see what it actually is at. Is there anything I can do different?

[ImiTek]

So on rx7 use a 220 ohm pull-up resister this will be better than the internal pull-up empty 3.4v full 0.3v

Disable the dash pull-up 1k

This will sort all your problems

[ImiTek]

You still get fluctuating but because the rage is larger it makes less of a difference overall

This is all my numbers

This is moving sender outside vehicle
Full 0.3v
Half 2v
Empty 3.4v

Sender in tank with 1/2 liter reads 3.1v empty

5litters full 2.8v this can be reserve

9L is 2.5v when started goes to 3v

Extra 10L is 2v when started goes to 2.5v

Extra 10l is 1.5v when started goes to 1.9v

Extra 10l is 1.1v when started goes to 1.5v

[Pirana]

That's awesome information! Is your setting on 0-90ohms, 90-0ohms ?

Thanks!

[ImiTek]

Myn on 90 -0 don't think it matters

[ImiTek]

Sender reads 1.340kohms full
And empty reads 1.417kohm
That this changes when you put voltage to it

You could probably work out new readings from all info but ant nobody got time for that

I've left myn in liters I've not yet setup full tank yet only upto 39L as fuel stations out of fuel where I am that will be one more adjustment anyway not big deal

But went on test drive and from 39L on heavy acceleration drops to 38L then back to 39L.

I'm happy with this