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

 

[piper184]

There is a single steel strap that runs from side to side. There was a rubber sleeve for the strap but nothing for under the tank. Also the tank mounting plate bolts directly to the bracket that sets down over the steering box.
In this picture you can kind of see the ribbed matting that is under the tank. I assembled this tractor from the crate myself. There were no extra parts. At the time I did not like the idea of bare metal tank resting on bare metal plate so I added the ribbed rubber mat to prevent fretting between the surfaces. It was some left over tool box drawer liner I had on hand at the time.

The mounting plate and brackets were all installed at the factory. The tank was in place but tipped so the filler neck pointed towards the seat. All I had to do was loosen the strap, set the tank in place and tighten it down. And add the ribbed mat.

Some vibration isolators would be nice but they would have to be pretty low profile to not raise the tank too far. I'd have to take a close look at excess thread length on the strap to see if a new one would need to be fabricated. I may have some low profile Lord style mounts in some old computer parts. They would be very old and likely either rotted or hard as a rock. I think I know which box in the shop to dig through.

In other news, my KUS system arrived today and I will try to get it mounted as soon as I have a chance to take things apart. I guess I better look for those mounts first!

 

[fidowanttobe]

I assembled mine also back in '07 and I did the same thing with the tank.
Be sure and let us know where you picked up that kit or a link and good luck.
Might want to stay indoors for the next few days anyway!!

 

[piper184]

OK, it is in and working. What an ugly project that turned out to be. But I sort of expected that. Here is a link to the sender/gauge combo I used:
FUEL TANK GAUGE METER SENDER 8" STAINLESS WEMA KUS UPFR-BB-240-33 BLACK GAS 8 " | eBay
First off, the new setup was just fine. The big problem I had was getting it to fit. That and messing with the hood. Fortunately I had changed the instrument cluster mounting so it was easy to remove. (I should make a new thread about that). Then the hood has always been a PITA to deal with. Had difficulties when I first assembled the tractor. I think I have made progress on solving that problem, might have to make a thread for that too.
The big issue was the Jinma fuel sender is not an exact fit to the standard sender mounting configuration. It is close but off just a little. The holes are clocked at the proper angles and were close enough that my crude measurements led me to think it was the international standard. The difference is the bolt holes are on a slightly larger diameter circle than the standard. Even holding the new gasket up against the old sending unit this was difficult to see. Only when I dropped the new sender into place with no gasket and looked straight down could I see why the screws wouldn't start into the flange. I didn't get a before picture but here is the new gasket setting on the flange and it is off just a little bit.

 

[piper184]

To correct this problem I decided to make eggs out of the holes on the new sender. A little hand work with a round file and soon it was doable. Ugly and not the preferred fix but without a lathe or milling machine this was the best I could do. Fortunately the new sender had a thick enough and large enough flange that this was possible. Then the next issue stuck it's head up. The new sender and the new gasket were considerably thicker than the original and now the mounting screws were too short! Since the design does not have the screws going all the way into the tank (good idea) you need the proper length screws or nothing works. I opted for using the old gasket which made the 10mm long screws just barely enough. For the new gasket I think 15mm length would work, but might have to add a washer if too long. Here is the modified sender. I own it now...

 

[piper184]

Next problem was finding a flat spot on the dash that would accommodate the new gauge. This is close to flat and acceptable. Then there was the wiring issues. The harness is short enough that when I moved the panel for access about half the wires for my switches pulled off. After finding a bad crimp and getting things back the way they were, the new gauge worked just fine even the backlight!
Someday I will re-wire this thing from the battery to the tail lights with proper quality wire and terminals. For now it functions and I have projects to do that it is needed for...

Oh, the hood problem, turns out the mounting brackets had the slots cut wrong and the screws all had to go in at an angle. A real PITA trying to install a washer, lock washer and nut in a blind hole. Some plasma surgery made a world of difference!

 

[piper184]

It just dawned on me the proper way to handle the sender screws being too short is to clean the tank flange threads really good and then install some studs with thread locker. Then the sender could be installed with washers, locks and nuts. Unfortunately I didn't have anything on hand to even make studs that size anyway. <SIGH>
I really need a nut and bolt store next door.... Oh, and a bearing shop and a hydraulic shop.

 

[Bob Rooks]

It just dawned on me the proper way to handle the sender screws being too short is to clean the tank flange threads really good and then install some studs with thread locker. Then the sender could be installed with washers, locks and nuts. Unfortunately I didn't have anything on hand to even make studs that size anyway. <SIGH>
I really need a nut and bolt store next door.... Oh, and a bearing shop and a hydraulic shop.

I would have installed one of those on the dozer if I didn't have to remove the ROPS, the hood, and the whole weldment for the wishbone lift cylinders. Very nice clean job btw.