hi i know i asked this before but i am in need of more information on the working on a fuel sender and gauge unit. it does not need to be on one in particulare just stuff on how they work


Tri

The sender usually has a float on a swinging arm, that rotates a potentiometer (variable resistor) as it moves. As the pot moves, it alters the voltage at the gauge, which in turn moves the needle.

That's my simplified understanding of how they work

Someone else may well know a lot more!!!

Nick

thanks for that anyone else know the alot more bits lol

Tri

you need to know whether your gauge reads full with high or Low resistance from the sender, ie some are back front to th others.

Say the float range gives you 30 ohms empty and 300 ohms full, you need a gauge that goes the same way or it will read empty when its full and vice versa.

Easy to test with a couple of resistors to test the gauge, it will tell yuou if its hi to low or vicy virky.

ie get a sender that matches the gauge. Same with any gauge that has an electrical signal eg Temp, or electric oil pressure (not capillary tube).

Have a trawl round the net, you will see the figure by the fuel senders etc.
it will give you an idea.

If your guage doesn't match the sender can it be altered inside to make it work?

the gauge usually has a bi metallic strip in it, coiled up into a spring. As the voltage heats it, the two metals expand at different rates and the coil will uncoil slighty, hence the needle moves. This is all powered by the float and variable resistor as described above. Obviously the markings are just added as required