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Discussion Starter · #1 ·
Does anyone know how to get at the wires attached to the top of the fuel tank sender unit on a Diablo. My fuel gauge is not indicating correctly and having checked out the gauge, I would suspect poor connections at the tank. I have read on the Forum that this is a past problem. Thanks.
 

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2008 Gallardo Superleggera (Arancio Borealis) | 1992 Diablo | 1927 Bugatti Type 35b
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is it still indicating something? Then it's not broken, it's just like that. Mine says empty when i've only used about 60% of the tank
 

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Discussion Starter · #3 ·
Diablo Fuei Tank Sender

Simon,
The fuel gauge sometimes reads correctly and other times zero. I need to get at the fuel tank sender unit to check the wire connections. Is it possible to gain access by removing the right rear wheel arch cover.
 

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You will get reasonable access to the top of the fuel tank (not sure about the sending unit) by removing the right rear wheel and those panels in the wheel arch, which is pretty much the same process you use on the left side to access/replace the battery.
 

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Discussion Starter · #5 ·
Diablo Fuel Sender Unit

Thanks David,
I have accessed the battery several times through the small left wheel arch panel.
I think the whole wheel arch panel would have to be removed on the right side. I wondered if anyone had removed it to get at the tank.
 

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Ian,

On the '91 - '93 models there are 3 panels that comprise the rear wheel arch. - the lower panel closest to the front of the car (it's metal with the louvers in it), the front upper panel, and the rear upper panel. If you remove the lower panel closest to the front and the front upper panel, you should get access to the tank. You have a later model Diablo, so perhaps yours is configured a bit differently.
 

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Discussion Starter · #10 ·
The sender unit must be off another vehicle, European I would guess but don't know which one. I'm sure you could use another unit provided it had the same fittings to the tank but you might have to make allowances on the fuel gauge. There is obviously a common fault with this system and my guess would be the electrical connections and not the sender unit itself as they rarely fail. I have checked out the fuel gauge and it's connections. That is why I need to get at the tank sender unit and check the wires and connector.
 

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I've heard this is a common fault with Diablos. Has anyone found the reason why the fuel gauge can suddenly read zero when below half full.
My car has had this exact same problem. The fuel gauge started working after I added Redline ST-1 fuel system cleaner to the fuel. First one bottle in half a tank, then two bottles in a full tank of fuel, let it sit for a couple of days... After the first bottle the fuel gauge started fluctuating between zero and the correct level while driving, and now after two more bottles the gauge seems to work! Maybe the mechanical parts of the sensor/float are sensitive to gunk left behind by old fuel?

Update: ... and sorry if I got anyone's hopes up. Just when I thought that the problem had disappeared, the low fuel warning came on although there was around 1/2 a tank of fuel left.
 

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I've replaced gauges, wires and fuel senders hoping to fix the problem. On all my three Diablos, the fuel gauges are useless.

On the Roadster it shows 1/2 when it's full, then empty within 40km.
On the SV it shows 3/4 when full, 1/4 within 100km then quickly to empty.
On the 2WD it shows full when full, 1/2 within 50km and then empty quickly thereafter.

Completely useless. I drive by the tripmeter.
 

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I have changed new sender and just want to double confirm it is now working . low fuel warning light turns on ( fuel gauge shows no fuel ) . But I can only manage to pump 50 ltr of fuel and the tank is full , fuel gauge now shows full tank as well . So I assume this is accurate , But I always thought we have a 100 ltr tank ?!! I am confused .
 

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I just noticed the cable in the middle is broken , so this might be the issue that it measures only 50ltr ( half tank) , I will check tomorrow and re connect the broken wire back see if this is the cause of the problem .


 

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are there two or three wires there? and what color are they?
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 !

 
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