New tank sender and gauge reads in reverse

[magpies]

I have discovered a problem with the Jaguar intank pump and sender unit. With the level sender in the empty position the gauge reads over full (pointer at the stop). Sender at a position which relates to about 2 gallon the pointer is at the full line. Sender at half tank and pointer is st half too. Sender at full the pointer is at the 1/4 line.

[mk1fan]

When I was specing Samy's in tank set up there were two types of wiring for the senders. IIRC correctly one was 'regular' earth, the other was 'positive' earth.

Can't recall which one Samy required but it might be that the Jag unit is the wrong type.

[magpies]

as the pump/sender is on the bench I tried both ways with the same result.

Have decided to have a vinyl sticker made to make the gauge show the contents with empty at the top.

[v8s4me]

Mine always shows 3/4 full except when it shows empty. Regardless of what's actually in the tank. Obviously your new gauge had detected that it has been fitted to a TVR and had decided to behave appropriately.

[GreenV8S]

I've always taken the view that if the needle moves a bit when it goes round corners, the tank probably isn't empty yet.

[greymrj]

A new one Mick, but only a new variation of the TVR ghost petrol level phenomena. Mine shows empty when full. Goes to full when half empty and then drops to zero while there is still plenty of fuel. Debs now records the mileage as we fill, but as the new engine is doing more to the tank we are always pleasantly surprised!!

[greymrj]

seem to remember saying a long time ago that your garage was on a hell of an incline!!

[TVRees]

To all,

Maybe cleaning the contact surface of the potentiometer on the level detector will help.

Not really appropriate, but I just did this on my 40yr old NAD amplifier and the result was amazing.

[magpies]

Ah. New Acoustic Dimension good value for money hifi

[mrufcs1]

Mick, have you put a multimeter across the sender to see what the range is (ohms) ? See thread on oil pressure sensor, the original gauges need 33-240 ohms. It doesn't sound like yours compatible.

[TVRees]

magpies said:

Ah. New Acoustic Dimension good value for money hifi

Designed in the UK, made in Japan.

What can go wrong !

[lordofthewings]

magpies said:

Have decided to have a vinyl sticker made to make the gauge show the contents with empty at the top.

Brilliant solution ! Mine is like so many others, it reads "FULL FULL hey I'm FULL" when the tank is sloshingly-full; then drops to show about half when it really is getting a bit low. Perhaps you could follow the I.T. department's advice, "...have you tried turning it off and on again ?". Anyhow basically every 250 miles or so I put a minimum of 40 quid's worth in. Mind you on my Grantura (and 3000S too as I recall) I used a hi-tec bamboo cane.

[Blue 30]

Mick...
As you have the sender on the bench, is it a wire wound variable resistance type ?
If so, the wiper will move away from one fixed end (of the resistor winding)' and obviously towards the other end.
You need the resistance to go down (towards 0ohms) as the tank fills..
Therefore it should be pretty straight forward to modify the prewired takeoff wiring to suit. That's assuming access can be gained.
TerryB