Electrical ? Fuel Gauge/Sending Unit Gone Berserk !!

[KoonHunter51]

2005 FarmPro 2430 4x4 (Jinma 305)
OK, Fuel gauge quit reading, so I did a little diagnose & found electric wires seemed OK, removed sending unit & it was in bad shape.
So, I bought a new gauge & sending unit & installed with no problem except poured the rain & filled gauge with water + gauge read full when really only 1/2 full.
Removed gauge & dried it out with a hairdryer & re-installed, reads correct volume now (1/2 tank) but needle is in a jumping contest.
Very erratic needle all the time jerking & jumping all over the place, engine running or not.
Put the old gauge back in, & no jerk/jump but no volume reading either.
I have attached the pictures of my tractor
Could I have the sender in the wrong position ?

Could it be wiring wrong ?
I have checked all the wiring & no noticeable contact problems.
This picture is of back of old fuel gauge (On the left), the new one has no bulb slot or black wire soldered to it, but it was wire exactly like this.

The old fuel gauge worked fine up until it died.
If anyone has pics or wiring diagram of this model 30hp wiring & sender location, I would appreciate.
Wiring diagram in manual shows 1 wire, but there is 3 on tractor, red, white, & black
Thanks, David

 

[KoonHunter51]

This is a little frustrating, but I could just stick a rod in tank to check fuel level
No luck yet, I checked wires & ground contact.
Gonna try a different gauge
I did get email to check on contacts touching inside tank sending unit, & looking at the old one not sure what to look for.
I guess I could drill holes & install some kind of site glass **NOT**

 

[jaotguy]

simply ground the white wire of the sending unit ... the gauge should read either full or empty ... no jumping around .... wiggle the wires and check for bad connections ...

then remove the white wire from ground ( and its post on the sender ) let it float in the air ... the gauge should flip the other way completely ...

if the gauge reads properly , the problem is the sender unit ( or a bad connection at it )... if it still jumps around with the sender out of the circuit, it is the gauge ...

 

[KoonHunter51]

Thanks jaotguy,
I'll try that
I'll post results
David

 

[KoonHunter51]

OK, Did wiring suggestion & did not get any action from gauge Needle must be broke or un-attached in new gauge
ohm meter shows resistance at sending unit wire
The erratic jumping around at the gauge has ceased too, but no volume reading
David

Update; Erratic back today

 

[cleat]

I had an oil pressure gauge do the same thing in my DF. It was a bad solder joint on the circuit board in the gauge housing.

Cleat

 

[KoonHunter51]

Erratic movement back today while bush hogging
I removed new sending unit & took small top plate off
Found loose components & broken wire
Will contact supplier for replace
Gauge needle is way past full & water still dripping from it
David

 

[KoonHunter51]

Still having problems
Got new sending/float unit & installed
Still have erratic needle movement, seems like there is a lot of movement/sloshing in the fuel tank ?
**BUT**
FUEL Gauge reads backwards; reads 1/4 tank when nearly full, & I switched wires & needle went to empty ?
The sending unit has a wire wrapped coil bar & I was thinking that bar needs turned around, but I looked at the old one & it is the same
These new Fuel gauge & temp gauges fills with water if left out or operating in the rain, supplier says most of them leak, but the old ones didn't leak

I think I might re-wire these two gauges, but not until I rectify the moisture problem
David

 

[KoonHunter51]

Well, I 've fooled with this snag for nearly a year with no results.
I just use a dowel down the tank so l do not run out of fuel
I had to get a sediment bowl/cut off unit so l ordered a new fuel guage
Wasted money, still no reading, but the needle does move slightly
I still have my dowel

 

[SPIKER]

same issue with mine, after the spring ran out of fuel w gauge reading 1/2 full... M