434josh Posted March 5, 2021 Report Share Posted March 5, 2021 I am not finding much in the help files but curious what it takes to display fuel level with a 73 ohm empty, 8 ohm full sender. I found a call file that I was able to setup and directed an analog input to that cal file but I am not sure if the ecu will read the ohms or only volts. Link Extreme G4+ Do I need an external ohms to volts converter or will the ecu read ohms directly? If it will, how is it to be wired? Thanks. Quote Link to comment Share on other sites More sharing options...
Adamw Posted March 5, 2021 Report Share Posted March 5, 2021 Ohms conversion is only relevant if the pull-up resistor is 1000 ohms. For fuel level you normally have a much lower resistance pull-up than this so the cal table should use volts as the input. Edit: This post here will give you an idea on how it needs to be wired: Quote Link to comment Share on other sites More sharing options...
434josh Posted March 5, 2021 Author Report Share Posted March 5, 2021 56 minutes ago, Adamw said: Ohms conversion is only relevant if the pull-up resistor is 1000 ohms. For fuel level you normally have a much lower resistance pull-up than this so the cal table should use volts as the input. Edit: This post here will give you an idea on how it needs to be wired: Thanks as usual Adam. I am not an electrical wizard but I can certainly duplicate this. Any advice on the specific resistors? The 100 ohm I can get locally are either 1/2 watt or 1/4 watt. Same with the 18k resistor. The cap would be 6.3v? Will all that work? Quote Link to comment Share on other sites More sharing options...
Adamw Posted March 5, 2021 Report Share Posted March 5, 2021 P = V2/R, so 5V2 / 100ohm = 0.25watts. The 1/4W resistor will get pretty hot with 1/4W going through it, so better go for 1/2W. 18K is going to use almost no power so 1/4W will be fine for that - but 1/2W is perfectly fine too. Cap rated voltage is not very important but the general rule is to de-rate by about 50%, so if your circuit will see a max of 5V, then you would go for a cap with at least a 10V rating. Quote Link to comment Share on other sites More sharing options...
CameronPausina Posted April 22, 2023 Report Share Posted April 22, 2023 Hi Guys Im looking to do the same thing with an FD RX7 Circuit car and display fuel level on a windows tablet dash. Working with an ohms range of 82 empty to 7.5 full, could anyone recommend the best way to connect the fuel level sensor wire to ECU input and what cal table to convert? Many thanks in advance. DenisAlmos 1 Quote Link to comment Share on other sites More sharing options...
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