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do you have your original sending unit? Here is a shot of mine, which shows two wires plus a ground, presumably one wire for the level and one of the low fuel light, plus a ground. I mistakenly broken my sending unit apart, and those two terminal feed separate wires into the sending unit, its not on a common terminal. At least i dont think they are on a common terminal.

Water Automotive tire Wood Road surface Grey
 

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There are 3 wires there , and I checked the wiring diagram 169 connector is a 3 pin connector but with only 2 wires are connected ( that’s probably the reason why the 3rd wire on my connector is disconnected ) . The wire color is correct orange/black .

The sender signal will go into GFU which will display on fuel gauge . I notice there is an inner resistance in the gauge , perhaps the gauge is the problem . From full tank to half tank measurement is accurate , once it passes half tank the gauge shows the fuel drops very fast and the low fuel warning light will be on.
When I refill the fuel I can only pump 50 lit max . So this tells me that I still have half tank full in my tank but the gauge shows empty , what I suspect is that once the fuel is below half tank level the gauge is no longer displaying the correct info . Very strange !
Found this on another site:
The ohm reading is 3.5 ohms full and 84 ohms empty. I am providing this as it doesn't appear in any Lamborghini repair manual.
 

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@JTSE30 thank you for that. These are NLA. Steve @ Driven Exotics uses a guy that rebuilds them. I am trying to find another alternative, and the VDO sites lists units as being 90Ohm range, which is what we need based on your information, thank you. I looked at my broken apart unit, and there are indeed two terminal with two wires going into the tube.
 

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Not to confuse folks 😇
But I always thought fuel sender units have a ground wire(normally grounded to the top of unit), a voltage wire to activate the fuel pump and another wire to provide the ohms for fuel gauge reading. Am I missing something?
 

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97.0 Diablo VT Roadster / 08 Gallardo Spyder
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Agree with Sledge. Also, to be clear, my fuel sender works just fine (full all the way down to low fuel light comes on) and the photo that I provided above is the only wiring off of my sender unit. There is that side terminal that is un-used and frankly I don’t understand what it would be if it was used, just the two wires shown in my photo.
 

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Why suspect it’s the problem?
Can’t you supply voltage to see if the gauge goes up and down?
Yes I suspect the gauge accuracy is the issue , i tested by supplying constance Voltage , the needle stops at different position each time I test . But when I link up to a 0-90 ohm sender and moves the level up/down , the gauge displays accurately . This is strange that’s why I am not too sure but I suspect it is the gauge issue since my sender on my car is brand new.
 

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@JTSE30 thank you for that. These are NLA. Steve @ Driven Exotics uses a guy that rebuilds them. I am trying to find another alternative, and the VDO sites lists units as being 90Ohm range, which is what we need based on your information, thank you. I looked at my broken apart unit, and there are indeed two terminal with two wires going into the tube.
Steve is only partially correct. The original VDO sending unit is available new for $67 as a 2 wire version. The only difference is that the 2 wire version doesn't activate the red light when your almost empty. That's what the third wire was for.

You can read my post below for more details.


The only mistake was not calling my friend Claudio Zampoli, prior to ordering the unit as he maintained a master list of suppliers for parts for all Lamborghinis and his Cizetta. Claudio verified the part listed in my post.The Cizetta and Diablo share an amazing amount of parts. Claudio even had the shop time estimate for doing this repair, which was 8 hours. He walked me through the procedure as well. Too bad he passed away as he was a wealth of information that you could rely on being accurate.
 
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