ausmini :: View topic - Fuel Tank sender??? - Works without the Earth wire???

The tank sender is grounded against the fuel tank by the metal on metal contact of the retaining clip. The fuel tank is grounded by its contact with the body. Both these ground contacts are purely unintentional, as the sender retainer was painted and not physically screwed down, the fuel tank strap once had a cork gasket between it and the tank, and the tank itself once sat on a piece of hessian.

What all this means is that the tank being connected to ground by its own physical contact with the chassis was not a guaranteed proposition, the black wire on the sender is instead a known good earth to make up for this.
So...yes it doesn't specifically need the black wire, but it's good electrical practice and prevented potential warranty issues to provide one.

Use a multimeter as it was spelled out in an earlier post to measure the resistance the sender provides for the float in the full position and the empty. This will decide the problem.

Author:	Lockie91 [ Thu Aug 13, 2009 7:25 pm ]
Post subject:	Fuel Tank sender??? - Works without the Earth wire???
Hi guys, Have been fiddling around with my fuel tank sender on the mini today. I've been having problems with the sender reading full all the time. I found that when I take the earth wire off the tank that the sender in the dash still reads full. It is only when I take the positive wire off, that the sender will begin to fall to empty. The wires are defentely making good contact so can't be that. Does anyone know what my problem could be?? Thanks guys. Lockie.

Author:	Mick [ Thu Aug 13, 2009 7:43 pm ]
Post subject:
The tank sender is grounded against the fuel tank by the metal on metal contact of the retaining clip. The fuel tank is grounded by its contact with the body. Both these ground contacts are purely unintentional, as the sender retainer was painted and not physically screwed down, the fuel tank strap once had a cork gasket between it and the tank, and the tank itself once sat on a piece of hessian. What all this means is that the tank being connected to ground by its own physical contact with the chassis was not a guaranteed proposition, the black wire on the sender is instead a known good earth to make up for this. So...yes it doesn't specifically need the black wire, but it's good electrical practice and prevented potential warranty issues to provide one. Use a multimeter as it was spelled out in an earlier post to measure the resistance the sender provides for the float in the full position and the empty. This will decide the problem.

Author:	Tombo [ Thu Aug 13, 2009 8:24 pm ]
Post subject:
Probably a stupid question, but have you tried swapping the wires on the terminals?

Author:	Lockie91 [ Thu Aug 13, 2009 11:06 pm ]
Post subject:
Tombo wrote: Probably a stupid question, but have you tried swapping the wires on the terminals? yeah I have, however you can't change them ova as they have different size conections, for this very purpose of getting them not mixed up.

Author:	Lockie91 [ Thu Aug 13, 2009 11:11 pm ]
Post subject:
Mick wrote: The tank sender is grounded against the fuel tank by the metal on metal contact of the retaining clip. The fuel tank is grounded by its contact with the body. Both these ground contacts are purely unintentional, as the sender retainer was painted and not physically screwed down, the fuel tank strap once had a cork gasket between it and the tank, and the tank itself once sat on a piece of hessian. What all this means is that the tank being connected to ground by its own physical contact with the chassis was not a guaranteed proposition, the black wire on the sender is instead a known good earth to make up for this. So...yes it doesn't specifically need the black wire, but it's good electrical practice and prevented potential warranty issues to provide one. Use a multimeter as it was spelled out in an earlier post to measure the resistance the sender provides for the float in the full position and the empty. This will decide the problem. oh ok I see. I don't have a multimeter so I was just trying to see if I could fiddle around some more to solve the problem. Looks like I will have to go see a mate who has one in the next week or so, and check it out. Thanks heaps for the advice Mick. Cheers Lockie.

ausmini https://www.ausmini.com/forums/

Fuel Tank sender??? - Works without the Earth wire??? https://www.ausmini.com/forums/viewtopic.php?f=2&t=56031	Page 1 of 1

Author:	poeee [ Fri Aug 14, 2009 8:28 am ]
Post subject:
Lockie91 wrote: I don't have a multimeter... I think you should buy one this weekend. For $10, there is no excuse to not have one. http://jaycar.com.au/productView.asp?ID ... BCATID=546

Author:	Wombat [ Fri Aug 14, 2009 9:18 am ]
Post subject:
poeee wrote: Lockie91 wrote: I don't have a multimeter... I think you should buy one this weekend. For $10, there is no excuse to not have one. http://jaycar.com.au/productView.asp?ID ... BCATID=546 Or spend a little more ($30) and get a buzzer on the continuity tester and auto off function - both very handy features http://jaycar.com.au/productView.asp?ID=QM1320&CATID=12&form=CAT&SUBCATID=546

Author:	Lockie91 [ Fri Aug 14, 2009 9:54 am ]
Post subject:
wow!!!! if I knew they were that cheap I would have got one ages ago That's the first thing on my shopping list for tomorrow now Thanks heaps guys

Author:	Mick [ Fri Aug 14, 2009 11:35 am ]
Post subject:
Love the jaycar multimeteres, I used to have to spend $110 15 years ago to get a Fluke 90 with volts, ohms, capacitor and diode. Now for 40 bucks you get everything there is, and unlike old analogue multimeters you can never blow yourself up by leaving it on ohms and testing a live 415 voltmeter.....and Jaycar is a name you can trust. God love the chinese and their small hands

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