electronic fuel gauge By famousbyter (Read 26,263 times)

[famousbyter]

Heys guys, I have an electronic fuel gauge that I want to install.
It has 3 wires (power, ground, wire to fuel sensor)

The fuel sensor itself has 3 wires that are in a plastic harness

Do I need to strip one of those wires and connect to my new fuel gauge wire?

I have already connected the power and ground and it lights up fine, it just reads empty.....

[jct842]

You need to either tell us what scooter you have or find the wiring diagram in our library and wire it as diagram indicates.

[Bashan]

You're right John, a diagram always helps. Famousbyter (great handle), if you'll look on this generic diagram, you'll see that the GY6 fuel gauge usually has a black DC power feed and two wires that run to the sending unit. The sending unit actually gets power from the gauge and then it has it's own ground. So I'm guessing hook the power feed up to the gauge and then both remaining wires hook onto the sending unit's wires. I'm not sure which one the ground would hook onto. Since it's DC it probably will work one way and not the other. I doubt you'll do any harm if you hook it up wrong but who knows? Rich

[famousbyter]

Hey rich, I wired it up like you suggested and it seems to be working fine when the bike is not moving. When I start it up and it is idleling or when I take it out for a ride, the gauge starts to read from where it was when it wasn't moving all the way down to zero and it just fluctuates randomly between those numbers. Any ideas on how to trouble shoot. Thanks......

[Bashan]

I need to know something, does it work OK with the key on but act up as soon as the engine starts? Or will it operate OK with the engine running but act up as soon as there's any motion? Also, check the ohms through the non-ground wires on the sending unit side of the harness. Rich

[famousbyter]

exactly, it seems to be registering right with just the key on. When I actually start the bike, the electronic display starts to move somewhat randomly. When I start to move it goes bananas. I have a voltmeter, but I really dont know how to set it up properly to check ohms. To be perfectly honest I dont know how to use it. The electronic fuel gauge I got has (2) extra wires in addition to the black power wire and the other two wires.. The instructions says in order to calibrate the gauge properly you have to clip one wire for 0-90 ohms, cut both wires for 10-180 ohms. Get back to me when you get a chance, thanks Rich

[Bashan]

OK, here's my understanding of these things but it's not my strong suit. If you have a two wire sending unit it uses a bimetallic strip that bends in the gauge with heat similar to a turn signal flasher:

Now here's where I could be wrong so anybody feel free to jump in and correct me. A three wire sender has a slightly more involved resistor system that in effect sends two inversely varying voltages to two coils in the gauge. As one current increases the other decreases pulling the needle back and forth:

Here's a common three wire sending unit with it's resistor:

You'll notice on this sending unit that when the float is down the blue wire has little resistance (low ohms) allowing a high current to it's coil while the yellow has a high ohm reading, this would pull the needle to empty:

The opposite is true when the float is high:

I have no idea how to calibrate a digital gas gauge. But you said you need ohm readings so this is how you do it. Set your multimeter to this position:

Use the select button to toggle through the functions until you get to ohms:

You don't want continuity for this, it will also show ohms:

Then put your black lead on the ground and the red on one of the other wires as you saw above.

However, the problem may lie with the interference from the AC power feeds in the system. That may be why it's fine until the stator starts spinning. Even though the gauge works off of the DC power, scooters are notorious for erratic AC and DC power. You may need some sort of filter for the gauge and most of the digital gauges I saw online came with their own dedicated sending unit. Your gauge may not even work off of an analog type signal. I'm not sure, this is new stuff to me. Rich

[sprocket]

I believe you need a sender designed for electronic fuel gauges...the ones in most scooters are analogue, really the float simply acts as a moving centertap on resistance coil, which varies the resistance and changes the needle on the guage...

There are scooters with electronic fuel guages..but I have no idea what type of sender they use..they may work on voltage change within the gauge rather than straight resistance

[royldoc]

What kind of electronic gauge did you get? Is it for auto use? You need to match the sending unit and gauge or the gauge to the sending unit, witch ever the case may be. I have cyberdyne cobalt blue digital gauges in my 94 explorer. I have oil pressure,temp,water temp,volts, and a tach. I didn't get the fuel gauge because it still worked.

Roy

[famousbyter]

I believe my gauge is designed for cars but I asked their tech support before purchasing and they said I would have no problems. Once again, I should check with you guys first before taking the word of people wanting to sell their products. I always do things the hard way. The gauge works fine as long as I'm not moving, which is better than having no gauge i guess. In the mean time I will try and find a sending unit that works with digital gauges. Thanks to everyone for all the comments and suggestions.