New fuel guage

The fuel gauge on my John Deere gave up. It comes as part of the entire
instrument panel. There's a reason they paint John Deere green, you need
lots of it to buy a part.
Anyway, I ordered a fuel gauge from Bumper Bumper. Its 10 to 73 ohm empty.
The Johnny sending unit is 4 to 97.5 ohm empty. I need to improve on the
range compatibility a bit if I can. I'm most concerned about the empty side,
if you've ever reprimed a diesel in the field, you know why.
any suggestions on a resistor combo or other?
Karl

Reply to
Karl Townsend
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Quick follow up, I found a 0 - 90 at JC Whitney, so I canceled the Bumper order. haven't ordered yet? Is this the best I can do?
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Karl
Reply to
Karl Townsend
If the JD sender goes to 97 ohms at empty, your 10-73 gauge will show empty while there's still ample "reserve" in the tank. It just won't come off "full" as soon.
Don't sweat it. You won't run out of fuel. (and yes, I have primed one, and it's no fun without compressed air and a few tools. I built a tank cap with a Schrader valve in it to help pressurize the tank (1-3psi).
LLoyd
Reply to
Lloyd E. Sponenburgh
Ive had some good success with using trim pots to fine tune these setups rather than resistors. they are cheap and small and easily fit behind the dash or anywhere else. rather than having a big knob, they have a small screw that you turn to adjust. Even if you do get a gauge that meets your requirments you can probably tune it a bit better with a trim pot.
Shaun
Reply to
Shaun Van Poecke
Somewhat OT.
I understand gauges of this type are going to be showing up in quite a few 2008 model year cars:
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Jeff
Reply to
Jeff Wisnia
The original range was 93.5 ohms (97.5 - 4). The new one will have a range of 90 ohms. Add somewhere between 4 and 8 ohms in series with the 0-90 sender and you should be in good shape. I have never checked the current in such a system, but you will need to in order to pick a resistor with enough wattage capability. We can't estimate the circuit current from the data we have because we don't know what the rest of the series resistance is.
If you don't want to or don't know how to measure the current (at worst case), then you can try this: It's hard to imagine that the fuel gage would take more than 1 ampere, worst case, so: if 12 volt system, 12 X 1 = 12 watts if 6 volt system, 6 X 1 = 6 watts. Get a 10 or 20 watt 4 or 5 ohm wirewound resistor.
Pete Stanaitis -----------------
Karl Townsend wrote:
Reply to
spaco
First guess Google hit - "fuel sender resistance VDO" leads to:
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And from there (and a few more places including
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) I came up with this chart:
*****
0 Ohms empty - 30 Ohms full is Early GM - Cars and most trucks pre-1965, some trucks through 1968
0 Ohms empty, 90 Ohms full is post-1965 General Motors standard.
73 Ohms empty, 10 Ohms full (opposite) is 86 and earlier Ford, Chrysler, and VW Beetle Type 1.
10 Ohms empty, 70 Ohms full is Ford F-series trucks Pre-1987 with bimetallic gauge
15 Ohms empty, 160 Ohms full is Ford F-series trucks Post-1987 with magnetic gauge
16 Ohms empty, 158 Ohms full is 87 and later Ford cars.
260 Ohms empty, 33 Ohms full (opposite) is Stewart-Warner
10 Ohms empty, 180 Ohms full is VDO
*
****
If you can't find a sender that matches your existing John Deere gauge get a sender that fits the tank, and then get a gauge that matches the sender.
Here's an interesting one - a Universal Electronic fuel gauge that works with any range sender...
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Reply to
Bruce L. Bergman
Frankly, given the PITA value of diesel priming (the main reason I despise changing my fuel filter, which is the only time I have needed to do it other than when I replaced the leaky petcock) I don't give a darn about the fuel gauge. Mine, as it happens, is dead with all the other electricals except the starter. It's way down the to-do list to fix them. I can work as much of a day as I can stand without emptying the 16 gallon tank. I fill the darn thing up every night. If I only burned a half a gallon, I put in half a gallon.
If I had a smaller tank or a thirstier tractor, I'd fill it at lunchtime. There's just no point in running the thing around near the bottom, so precise fuel gauge readings are a pointless exercise. Oh look, I have 1/32 tank left - oops, I went on a hill and sucked air - now I have to prime the thing - so glad I didn't waste a minute putting fuel in when it got down below 1/4 tank...
If you are working far from whatever your usual fuel source is (such that driving the tractor back to it would be inefficient), get a few diesel jerrycans and bring them with you, full, to the tractor in the morning. When you shut down, fill it up, and take the empty or partially full cans back the main fuel supply for the next day. If you stop for lunch, put in what fits at lunchtime.
Reply to
Ecnerwal
Do you guys have priming pumps on your diesels? Priming my Onan DJE diesel, as well as Cummins L423D diesels is next to trivial. Either the hand priming pump, or just cranking a little does it just fine.
i
Reply to
Ignoramus3259
No hand pump. Have to crank, but also have to loosen injectors while cranking until no bubbles come out. It's the latter I hate messing about with. For some reason the way the pump works it won't simply pump and vent to the overflow line any bubbles, it needs the injectors loosened up to get them out.
Reply to
Ecnerwal
I thought that bubbles would go into overflow lines. Live and learn.
i
Reply to
Ignoramus3259
What model JD is it? Most JD have a wire with a cork. All you need to do is bend the wire to calibrate empty. I can maybe give you some pointers on bleeding it. I've done it many times in the last 40 yrs.
Karl Townsend wrote:
Reply to
Ralph Henrichs
In my experience, injector pumps take it pretty hard when they don't have fuel as that's their lubrication. Two stroke Detroits don't seem to mind so much, but it still don't help 'em any.
John
Reply to
JohnM
Bend the wire was gonna be my suggestion...
FWIW, put 2 new fuel bladders in the Cessna-182 about a year ago... ya have to bend the senders a bit to get them out, so ya gotta re-bend em when you re-install them...
FAA regulations state that the ONLY time an aircraft fuel gauge must read correctly is when it's empty... and empty is define by the manufacturer as to a certian ammount of 'un-useable' fuel in the tanks... soo.. ya dump in how ever much gas is 'empty' and bend the wire so the gauge reads 'E'...
Oh and if you guys are pissed about the price of auto gas, be glad you aren't buying 100LL...
--.- Dave
Reply to
Dave August

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