fuel gauge problem By tavcor (Read 1,311 times)

[tavcor]

hi i recently bought a Jonway master 2. the fuel gauge only start to register at half more than half it would go down flat and only come up once i reach half a tank. the previous owner put in a switch to manually control the fan i want to put it back to automatic. had some heating problems i took the thermostat out can i run without a thermostat.

[alleyoop]

That sounds like the Float assembly is in UPSIDE DOWN. If upside down when full it will register EMPTY and as the fuel goes down it will start to register.
So take the Float assembly off and and flip it 180% .
Alleyoop

[tavcor]

Thanks will do that

[tavcor]

Try it did not work will flip it again once fuel dropped. Anything else I can try

[alleyoop]

Were is your tank above the seat or in the hump up front? Also where is the Float Assembly on the top of the tank or in the middle facing toward the rear. IS IT SQUARE held on with 4 nuts or ROUND that snaps in? The only other thing I can think of that would cause it to register EMPTY when full and start registering at half is that the plug or wires are backwards or maybe the wires going to the gauge are backwards.

But you can test it pretty easy, Just take the assembly out and change the wires and move it up and down with your hand and see if it registers correctly. When the float is up see if the gauge registers full and when down empty all outside the tank.

Take a pic of the assembly here are pics of mine.
Alleyoop

IN THIS POSITION IT SHOULD REGISTER EMPTY:


IN THIS POSITION IT SHOULD REGISTER FULL:

[tavcor]

hi Alleyoop mine is like yours square fastened with 4 nuts in middle of the tank not on top. where do i dismantle the wires for switching?

[tavcor]

mine are positioned just like yours in the pic so it must be the wires. do i switch at the float or behind the gauge?

[alleyoop]

If that is a used scoot they may have put in a new instrument panel so switch the wires there first IF the sensor is in the right way. But before you do any swithing make sure the sensor is in right not upside down. Notice where the wire that holds the float goes into the holder THAT is the top as you put it in.

But even before you put it back in, turn the key on and move the float up and down and see how registers. Then if holding it in the right position it registers the opposite look at the wires where it plugs into. The plugs only fit in way into each other one. If that looks good then look in back of the instrument panel they may have put in a new instrument panel and hooked the wires wrong you can try switching the wires there.
Alleyoop

[tavcor]

hi Alleyoop sensor is in correct at back of cluster looks like there's 3 wire do i swop all 3 or just the 2 colours

[nitewing44]

It sounds like the float is positioned in the shallow part of your tank. Reposition it to travel in the entire tank. You should be good to go.

[tavcor]

how do i go about reposition it Nightwing?

[alleyoop]

I just re-read your original post:

hi i recently bought a Jonway master 2. the fuel gauge only start to register at half more than half it would go down flat and only come up once i reach half a tank. the previous owner put in a switch to manually control the fan i want to put it back to automatic. had some heating problems i took the thermostat out can i run without a thermostat.

WAIT JUST A MINUTE I THINK I MISUNDERSTOOD what you THINK is a problem.

ARE YOU SAYING: that you fill the tank up and it shows FULL until the tank is ABOUT HALFWAY THEN it starts to register as being HALF FULL or SO???

IF SO I KNOW what is going on and will explain.
Alleyoop

[tavcor]

no Allyoop when filled up it will lay flat at empty until the tank reach about half then only will it start to register. the gauge will never go up to full even if i fill up. what wires should be swop black or the other 2 colours? i am thinking of buying a new sensor.

[alleyoop]

Look in back of the instrument the wires going to the GAUGE:

As you look at them the BLACK wire should be on top, then a WHITE/BLUE in the middle and the bottom a YELLOW.
Alleyoop

[ellpee]

I'm learning as I read, but also chuckling -- I too find it hard to ignore gauges that don't work 100%. On my Roketa the fuel gauge works reasonably well, goes to full on fill-up and gradually down, although when it's almost at <E> I still have about a gallon left. I've developed the habit of just using mpg; I know I get right around 75mpg, and have a roughly three-gallon tank, so when I get to 150 miles it's time to hit the pump. Only flaw in my simple system is that my odometer doesn't roll over, so I have to remember to zero it out when it hits 100 the first time! Always something, ALWAYS some darn thing. Good luck getting your fuel gauge up to spec.