Back in the day, working at Flexdrive Instruments, the Aussie arm of Stewart Warner, the tank senders were always set slightly low at full. For instance the 73-10 ohm tank the 10 ohms would be set at 9 ohms so the gauge pointer would read slightly above full. Apparently, back in the day, people liked their fuel gauge to read slightly above full. Gauges were always calibrated exactly on the mark. Low on the sender would be set at correct ohms or a little higher like 75 ohms would be acceptable. These days, when ever I repair a tank sender I always set them the same way as it was done at the factory, always a little higher at the full mark (9 ohms) but never higher than the 10 ohms. Anyway, just 2 cents worth from the old school instrument guy. 🙂
Interesting, but the "fix" by setting stops on the float motion effectively makes it non-responsive around the F and E limits. At least keeps the customer happy since they see exactly full on the dash gage. More critical is how accurate it reads near empty. Perhaps the stop is why most people figure they can keep driving a bit more when it shows "E" on the gage and the needle stops moving.
What aftermarket fuel gauge do you recommend to use with the Crown sending unit? I want to use it on my 1980 CJ5. Want to keep the speedo cluster in the dash. Thanks.
My car uses a different style unit that won’t allow me to bend tabs to adjust the reading my manual calls for 3ohms full/80ohms empty the replacement unit I received reads 6.5omhs full/82.5 empty will that cause an issue ?
The purpose of changing the filter in the tank prevents any impurities from going through all your lines before your in line fuel filter .. you're going to have a higher chance at general wear throughout everything before the in-line filter
I rebuild senders professionally and this is not how you calibrate a sender. The two stops are intended to keep the float arm from hitting and drumming on the top of bottom of the tank. The actual calibration is done inside the resistor housing by adjusting the location of the sweep arm. As Ellesmere Wildwood pointed out the resistance at full should be no higher than 10 ohms. Setting it a little lower compensates for the series resistance in the rest of the circuit. As a percentage being 1 ohm off at 10 ohms is meaningful. At 73 ohms empty one ohm makes exactly no meaning full difference. Because of the design these senders are only calibrated at the full position. If the empty reading is too high it means that you are compensating for series in the connections in the sender by having to really drop the full setting to get total resistance in the sender down to 10 ohms.
Hi William…So, with a full tank, my gauge says I am a hair above half tank. When I am empty, my gauge says I am around a quarter tank. How do I get full to be F and empty to be E?
@@jjpaul75 The speedometer is typically driven by a mechanical cable. The number of teeth on the end of the cable determines the ratio. If yours is like that then you need a gear with more teeth. Or it could be an electronic speedometer and that is entirely different. What vehicle?
What ohms setting on your multimeter do you use? I want to calibrate my Crown sending unit for my 80 CJ5. Tank is a 15 gallon poly tank from MTS. Thanks.
