Fuel gauge not working - whats up?

Whole in the Water

Well-Known Member
My fuel gauge which I replaced 5 years ago suddenly stopped working on Sat when out fishing. Anyone have any thoughts on why and what it most likely could be before I start taking stuff apart?
 
Check to make sure all connections to sending unit and gauge are clean and secure
 
Yep start at the tank itself, clean the connections they're likely corroded. I did mine this summer finally to correct an erratic reading and surprise all good.
 
Yup. Sending unit wires probably. Mine are very exposed and don't take much to get corroded and/or damaged.
Reminds me of issue I have with inaccurate gauge. Just replaced sending unit but it still reads more fuel than I have which sucks. Gas swishes around in my tank more than I like as it is low and long also.
Anyone know if there is an adjustment for accuracy on these?
 
Float with swing arm type senders are pretty vague because of fuel sloshing around. Modern digital senders use a Reed system to scan the tank level dozens of times a second to give an averaged fuel level. Fewer moving parts - and less movement in those parts - makes them accurate and reliable. Of course as always they cost more and also must have the correct length sender for your tank.
 
To check the guage and wiring to the guage. Simply disconnect the wire from the sender and touch it to ground. The guage should spike to full I believe. If it does. You know it's the sender.
 
Float with swing arm type senders are pretty vague because of fuel sloshing around. Modern digital senders use a Reed system to scan the tank level dozens of times a second to give an averaged fuel level. Fewer moving parts - and less movement in those parts - makes them accurate and reliable. Of course as always they cost more and also must have the correct length sender for your tank.

Any links? Mine works but its not overly accurate and I'd like to have a better idea of my overall range. Google time...
 
Any links? Mine works but its not overly accurate and I'd like to have a better idea of my overall range. Google time...
Yes, corrosion. I had to take my sender unit apart and clean it up to get good connectivity. Works like it should, now.
 
I bought a life time supply of dielectric grease last week and cleaning the connections properly at the tank was the first. Haha
 
General principle, use home runs for ground rather than trying to find (and keep clean) frame grounds. Self evident in a glass hull perhaps, not so much in aluminum or automotive. If you get a good quality fuse block such as Blue Seas, they have the grounds all broken out one per circuit. No piggybacking multiple terminals onto one screws or jamming several wires into one ring terminal. If a ground issue develops, you know where to look for it: at the device or at the fuse block, not some random other location (possibly inaccessible).

I did this when I rewired my trailer, every light is a home run so their terminations are all up front by the winch. Yes it uses more wire but has been 100% reliable over four years so far.
 
My fuel gauge which I replaced 5 years ago suddenly stopped working on Sat when out fishing. Anyone have any thoughts on why and what it most likely could be before I start taking stuff apart?

Stopped working? How? Pegged past full on a half tank? Needle frozen power on or off? Needle sitting on the pin below empty?
 
Mine stopped a few weeks ago. Was working just fine. Put the boat on the trailer to go fish elsewhere. Upon putting the boat back in the water, the gauge stayed on empty. Turns out that the gauge needle actually broke off at the base. Replaced gauge and all turned out just fine. Sometimes things just break.
 
Use a multi meter check the ground to the sender by removing the wire at the sender and put one meter lead on the negative battery termial and the other to the ground.. should be low reistance(0.2-0.5 ohm) not an open circut or high resitance in that wire.

if that checks out

pull the sender from the tank(or you can cheat and rock the boat to slosh the fuel) and use a multi meter and check the resistance(at the sender) as you actuate the sender through its range the reistance should change . if the resistance does not change or reads zero the sender is most likely garbage(you can probaby find your senders resistance values on-line or on the sender it self). if that all checks out hook the sender to the wires and check resistance at the gauge connection if that all checks out it would most likely point to a bad fuel gauge.

but as said by others above always do the easy stuff first...poor connections and corrosion are typically an issue .

* i went through a similar issue about a year ago...i have two tanks and one tank always read full even though it was not...turned out to be a problem internally with the rocker switch (the switch swapped between tanks on the single indicator) that caused i believe high resistance in the sender wire that gave the indication of a full tank all the time. installed a new switch and gauge now indicates normally.
 
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