I just installed a new fuel gauge in dash and it has an E-F of 0-30 but my in tank sender has a range of E-F of 0-300. Is there a way to add an inline resistor to change the value to match the gauge? If so, can someone tell me what resistor value I need?
You would need to add a resistor in parallel with your sender to decrease the resistance. You could put a variable resistor set to around 50 ohms, and see where that gets you. When you have fine-tuned the resistance, remove the variable resistor (potentiometer) and measure the resistance. A suitable fixed value resistor close enough can then be fitted. Just dont screw the resistance below about 30 ohms or you may be putting a near-short into the circuit and fry the gauge.
What fuel tank is it (what car? ) and what kind of sender? I've never heard of 0-300. I have heard of 0-30, it was used in most GMs from the 1930s- mid 1960s. If you add a resistor in series to get it to read properly when it's full, it will never show less than about 90% full. If you add a resistor in parallel, it will continue to read near empty.
You’re not going to get there with a resistor. Best answer is changing the sender to match the gauge. Possibly OT here, but I have one of these and it works well. Matches any sender to any gauge, and provides anti-slosh so my gauge no longer bounces all over the place going down the road. https://www.speedwaymotors.com/Classic-Instruments-SN34-Fuel-Link-Interface,230181.html
There are a bunch of those adapter boxes from different suppliers, it might be the way to go if it's not easy to change the sender.
What kind of car? If it's an older Ford, it has a gauge system that works on the King-Seeley principle, which is incompatible with your gauge.
I have a 1968 Corvette that I did an LS swap. I have a Holley in-tank fuel pump and sender and according to their website it reads at E-F 0-300 ohms. I just replaced all my old gauges with a set of New Vintage USA. They say their fuel gauge reads E-F 0-30.
Are you sure it doesn't say 0-30 Ohms? And the O in Ohms looks like another zero? But their web site says the 68 Corvette pump assembly 12-311 has a 0-90 Ohm sender, which is what the car should have had originally. Some time in the early-mid 1960s, Chevy switched from 30 to 90 Ohm senders, and used different gauges to match.
A lot of the NVU gas gauges have dip switches on the back to set the ohms to the most common ones. I also have not heard of a 0-300 range.
After some more research, the Holley might be 0-90 ohms. I need to call Holley to confirm. If it is, then the new gauges have a selector where I can change that internally.
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