Jinma 284 fuel sender

[piper184]

The second fuel sender in less then 800 hours has failed. I think the first one lasted 300 hours and the replacement lasted maybe 100.
I took the first one apart and in spite of it having redundant contacts on the swing arm/resistor it was worn out to the point it was no longer making reliable contact. This one has shorted to ground somehow and always shows full. Less than helpful...
The instrument panel part works fine, it is just the sending unit that goes bad. I suspect vibration from the engine kills these units. If the tank were mounted somewhere else it might be fine.
Any alternatives that I can think of require adding a secondary gauge somewhere. While it would be preferable to use the existing instrument, finding a sending unit with the proper resistances, length of movement (and vibration tolerance) might be a challenge.
In the experimental aircraft world they use a capacitance type sensor that is "tunable" to tank size and the related electronic readout.
I am beginning to think old school, mechanical float gauge or some kind of sight glass and leave the electronics behind. Piper Cubs used a float ball in a sight glass...
Does anyone have any ideas for an alternative sending unit or fuel gauge setup?

 

[Bob Rooks]

This type is used on EMD expansion tanks that are mounted on the engine. They usually require replacement around 15,000 hrs. Note that they come in different lengths to suit tank depth.

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[Bob Rooks]

Is there room to install vibration isolators on the tank?

 

[Bob Rooks]

ESF Fuel Level Sender

 

[piper184]

Thanks Bob. These are similar to some others I was looking at. When I replaced it last time I made note of the full and empty Ohm readings of the new sender. Now I need to locate my notes.
If I can find a sender with the correct range of motion readings even at different ohms I can compensate by adding resistance with a resistor in series or reducing with one in parallel.
The tank is strapped down to a steel bracket that is bolted to the tractor and instrument cluster framework. All vibrations are transferred directly to the tank and a float arm on a lever magnifies the oscillation back to the hinge point and the resistor wiper assembly. I installed a piece of drawer liner mat from my tool box between the tank and the bracket when I put the tractor together. AT the time my main concern was fretting between the two surfaces wearing a hole in the tank. I need to do some measuring to see if there is enough clearance under the hood to install dampers.
I'll do some more digging into this in a few days when I have more time for accurate measurements and in depth shopping. I'll keep you posted.

 

[piper184]

The tank is steel with a raised filler neck. The tank itself is 9" tall. The sender mounts on a flange with 5 bolts. The bolt pattern apparently fits the the SAE standard flange size, at least as accurately as I can measure.
The document about resistances I have says that full is ~75 Ohms and empty is ~10 ohms. This would seem to fit the SAE specs although that range is 33 to 240 for American and 0 to 180 European.
However, the document is wrong. The Jinma sender has the high resistance at empty and the low resistance at full. I confirmed this by opening up the cover and observing the way the resistor was wired and also by shorting the sender to ground on the tractor causes the gauge to read full.
The KUS unit looked like the most viable to being able to use the original dash gauge, but since resistances are reversed that is out. All other sending units I could find work the same as the KUS which means $30 Jinma part is the only one that will work without adding an aftermarket gauge somewhere on the dash. Bummer...
The Jinma part is reasonably priced and available, but it is a real PITA to replace. Remove the hood, pull the steering wheel, remove the instrument panel and disconnect all the wires the remove the instrument panel housing so you can get to the top of the tank to replace the sender.
I'm still researching and thinking about options that don't involve doing this every 100 hours or so...

 

[Bob Rooks]

My excavator also has a nylon sight tube, but that is so foggy now I can't read it. I have to remove the tank to replace it, but in order to remove the tank I first must remove the cab, and that's not hapnin'. I'll leave that for the next guy. I have a calibrated stick. Recently I replaced the tank sending unit on the skid steer. Off-the-shelf universal senders fitted right up but would not work. I didn't bother with resistance readings (maybe it would've helped you if I had), but the new OEM sender worked perfectly. Machine is a '99 with 1,200 hours.

 

[piper184]

I bit the bullet and ordered this. As it turns out you have to put an 8" sender in a 9" deep tank. I'll consider the extra inch of fuel to be "reserve".
Any mechanical option was going to require modification and cutting holes in the hood.
This one will require drilling a hole in the dash for the gauge but I think there is room for it just below the stock instrument cluster.
Got this one from a domestic boat service place instead of ordering from China. This one should be better built than the Jinma parts.
Jinma sender was $30, this whole setup was $80.
I'll let you know how it works out.

 

[fidowanttobe]

Piper,
Please respond back on this because I am sure others, me included would like this upgrade. Mine has been unreliable since new. I don't have the dash cluster, just individual 2" gauges and the only oem ones left are the tach and fuel. I have been using KUS with good results so far.

 

[Affordable]

There are rubber spacers under the Bracket and the fuel tank ?? Maybe someone did not install yours when the tractor was assemblied

Tommy
Affordable Tractor Sales co
"Your Jinma Parts Superstore"
www.affordabletractorsalesco.com
979-865-4002