Ducie54 Posted July 13, 2021 Report Share Posted July 13, 2021 I have run out of scaling for my fuel gauge. I figure I need to use a resistor in series to drop the mv under 5 but unsure what size resistor to run. Is there any recommendation? Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 13, 2021 Report Share Posted July 13, 2021 Its a bit hard to see the pic, but it would be unusual for the fuel level to exced 5V as the pull-up would normally only be 5V from the dash. Is it still connected to the factory fuel gauge as well or something? Quote Link to comment Share on other sites More sharing options...
Ducie54 Posted July 13, 2021 Author Report Share Posted July 13, 2021 Yeah it was a poor pic that has been fixed. I tried with the pullup box checked and uncheck with the same results. It mentions about PDM only so I don't know if I have this feature available. Yes I still have the factory gauge connected as well. I have look at the FSM and the resistance when Full is 5 ohms and empty is 95 ohms Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 15, 2021 Report Share Posted July 15, 2021 Sorry for the slow reply. Do you know what voltage you have on the wire for empty? Quote Link to comment Share on other sites More sharing options...
Ducie54 Posted July 15, 2021 Author Report Share Posted July 15, 2021 0.85v when full and 5.6v when empty. Im maxing out the 5v limit. Looking at a voltage divider atm. Quote Link to comment Share on other sites More sharing options...
Adamw Posted July 15, 2021 Report Share Posted July 15, 2021 If you put a 100-200ohm resistor between the signal wire and ground that should drop your max voltage down to around 4-4.5V. MagicMike and Ducie54 2 Quote Link to comment Share on other sites More sharing options...
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