Fuel Sender

[JackIIA]

Can a diesel 88" gas tank sender unit be used in a petrol 88? I received a diesel sender unit (pictured below) instead of a petrol one. I know the petrol ones are hard to come by.

There is notch on the float arm of both the petrol and diesel versions that appears to allow you to remove and then interchange the arms. But with some light torquing pressure, I get no release, and don't want to break it if it doesn't unscrew.

Can't find a schematic of the diesel set up to better understand how this works. (anyone have that?)

Why would it ship with a float arm with no float, and then another arm with no threading but a float?

Weird.

[Wander]

It looks very much like the sender on my IIa (the original) and I don't know why it would work-they both float on the fuel level. On my sender the arm is doubled as if you attached those two pieces together with a clip on either end. mine is soldered. What is the hardware in the bag?

[JackIIA]

Matt - that's just a form shot from the web, I don't have the hardware in the packet.

My gut reaction is that to use this assembly in a petrol you pry the float off of the 'detached arm' and then bend the end of the arm coming out of the sender around it - and just toss the 'extra' detached arm.

I will say that the shape of this arm (dipped) is different than a petrol (straight) and wondering if this 'solution' results in an inaccurate reading???

[LaneRover]

When I replaced the sender in my 109 SW tank the sender came like that. You are supposed to measure the height of the tank and then attach the arm with the float to the arm on the sender itself. The little clamps hold it together either forever or until you have it soldered.

[Terrys]

Lane's correct; you attach the two arms together with the clamp, so that the travel of the arm equals the height of your tank. (Pssst, your gauge doesn't care if it's diesel fuel or gasoline in the tank)

[JackIIA]

(Pssst, your gauge doesn't care if it's diesel fuel or gasoline in the tank)

LOL!

Thanks all.

[artpeck]

The only thing i would add having just replaced mine is that the little wire clamps that are supposed to hold the adjustable arm to the main arm are totally ineffective so once you have determined the appropriate length use a more permanent solution. I used some fine gauge baling wire that I double wrapped and twist crimped.

[scatterling]

The diesel one might work. When I couldn't find the senders for my military underseat tanks I ordered military specific ones from lrseries.com. What I got were the same setup as for the diesel. ( same item #'s) Haven't had petrol in the tanks yet so I can't say, but I also measured my old senders and cut the new rods and overlapped and soldered them. Hopefully it all works.

[TeriAnn]

What you have is a universal sending unit intended to be fitted to a large number of different cars, both petrol and diesel. That is why you set the length of the float arm for the height of your vehicle's fuel tank. This will work on all factory negative earth Land Rovers that still have a factory or factory like front or rear fuel tank.

The Land Rovers that came from the factory wired for positive earth requires an NLA sender unit identified by a little tower on the top side.

When I needed a new sender unit in my SII I used a negative earth MGB gauge on an aux. panel because it is compatible with the sender units currently available and looks right (I now have a MGB tach in the hole where the fuel gauge sat). I set the float arm so the float touched the bottom of the tank when empty, used the provided clamps then soldered the two arm sections together.

You asked about the wiring. There will be an uninsulated tab that you should wire to frame ground, a wire for the gauge and a wire for a low fuel warning light. The low warning tab is easy to verify as it is an on- off switch that only conducts when the tank is nearly empty. You can ignore this tab if you don't want to add a low fuel warning light.

[kwd509]

The Land Rovers that came from the factory wired for positive earth requires an NLA sender unit identified by a little tower on the top side.


I have been following with interest. When I begin the work on my 64 2a diesel in the next few months I expect that one of the first orders of business will be the fuel tank and associated components. With the exception of the tank all other aspects of fuel system have been cleaned and repaired. Sadly, that tank was w/o cap for many years and it was filled to brim with diesel water combo.....

So,
any projections on what might I find in terms of degraded components?
&
what are my options relative to sending unit, if it needs replacement. Am I compelled to go to negative earth?

[Terrys]

Am I compelled to go to negative earth?
No, but if you intend to upgrade to an alternator, you will need to convert to Neg. Earth.

The universal fuel sender, or any fuel sender, is merely a variable resistor (potentiometer, if you prefer) and it doesn't care what the system polarity is.
The fuel sender which is no longer available was a wire wound resistor, which was located above the mounting plate. The resistor never wore out, but the mechanical design wasn't the greatest, and the arm was prone to 'freezing'. All new senders today are carbon ceramic, and they do wear out. They work well in passenger cars where there isn't as much sloshing, but series trucks aren't as 'smooth' and the sender does alot of up-down wiping of the carbon film, shortening their life.

[yorker]

FWIW I am pretty sure I have seen Delco 10si + ground alternators but I don't know why you'd ever want to reatain the + ground system.

[JackIIA]

Gotta say. I am sometimes amazed at the depth of knowledge and practical solutions on the forum, even on something like a sender unit. Why I love the RN site. :thumb-up:

My unit didn't come with the clamps, but I'm guessing a soldering gun and some wound wire as Art suggested will do the trick.

[kwd509]

I just removed an aged and rusty diesel fuel tank. The fuel sender unit looks mechanically sound and the hand work on the float is is interesting. Would the device deteriorate simply form sitting 30 yrs? I'd happily reuse, if I can....
Also, I'm curious. is the positive polarity sender different merely in polarity? it sounds as if their is also some inherent design change.

[JackIIA]

Is it just my eyes...or is that a brass float(!). Very cool if so.

[kwd509]

Is it just my eyes...or is that a brass float(!). Very cool if so.

No it is stainless, still pretty cool., but tinted as it came out of the tank. It wipes off pretty easily.

Is there any way to test it?
if not, is it more likely that it will, or will not work?


thanks.
Jay

[JackIIA]

I would think if you hook of the terminals and then use a multimeter at one end to see if the current increases (as you lift the arm), that would answer your question. but, really, I'd also think if you just clean the terminals up and make sure it moves easily, it should be ok. just put in a new cork gasket. i replaced my unit just because i'm doing a complete rebuild and can't sleep at night if i don't see how much money i can waste on parts i probably don't need.

[kwd509]

I would think if you hook of the terminals and then use a multimeter at one end to see if the current increases (as you lift the arm), that would answer your question. but, really, I'd also think if you just clean the terminals up and make sure it moves easily, it should be ok. just put in a new cork gasket. i replaced my unit just because i'm doing a complete rebuild and can't sleep at night if i don't see how much money i can waste on parts i probably don't need.

"it should be ok", that's what I'm hoping for......as for money on parts, that is a difficult and expensive slippery slope.


Lastly, does the evolution of the sender unit mean that they did away with the low fuel warning light on diesels when they went to negative ground?

Thanks

[disco2hse]

No, but if you intend to upgrade to an alternator, you will need to convert to Neg. Earth.

Just for the sake of completeness:

http://www.lrfaq.org/Series/FAQ.S.elec_positive_ground.html

and

http://www.expeditionlandrover.info/polarityConversion.htm (thanks to Terri-Ann)

[JackIIA]

Lastly, does the evolution of the sender unit mean that they did away with the low fuel warning light on diesels when they went to negative ground?

No idea. Sorry.

[bmohan55]

For some reason I had a positive earth sender in my '72, the fuel gauge read backward!
Got a proline negetive and all is well now.

BTW, do you see the prices on a postive earth sender!!!!!!!!!!

[JackIIA]

Yeah. At more than $300 a pop, that should be an incentive to switch over to negative.

[Tbedman]

Cool pics on facebook. Where in San Diego? Timco3