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Can someone enlighten me as to how a fuel tap level sensor works? I have obviously got too much spare time on my hands. I have a spare with a broken float tube, fractured near the base.Today I thought I would try and investigate it.
After a bit of effort it is disassembled.Using a thin nail I managed to tap the brass float tube ,3,5mm in diameter out of the tap body. There is a float which slides between two brass collars. Internal to this is a wire which exists the tap . Alongside this is an earth wire which is attached to the rear of the tap by a small screw.
Having heated the brass to remove the collars and float, simultaneously melting the insulation of the internal wire, I cannot now figure out how the float action creates a circuit .The float is non conductive ,or at least it is now.Much prodding with a multimeter did not help.
Surely it cannot be this difficult?
John

May I be so bold as to suggest one needs gainful employment. Firstly, to stop you piddling about in the shed and secondly to ensure that anything in the house remains intact. Is this why you gravitate to the shed? You may also find the pub and the bookies are good places to be, as well as a ride out to a splendid tea shoppe in olde worlde Devon.

I thought the thing was either a reed relay (a magnet will slide up and down the tube) or, better still, when the float reaches a certain depth makes a simple circuit. Having never been so bored as to have the time to look, I don't really know and wonder why I answered you. Maybe I am bored, after all. Oohh, look, 16.40 nearly time for Four In a Bed and Pointless..

You are so right. I think it uses capacitance. Anyway I suspect my investigations were an antidote to glossing ten door frames in the past week. I was on a roll, having fitted a new iphone battery, new batteries in the old Dremel powerpack and rebuilt a pair of Bings.
Must buy a new project bike...........
John

My latest theory is that there is a micro reed switch ( who knew of such a thing?)inside the brass tube. The float has a magnetic ring at the top.
The conundrum is to try a normally closed one at the top or a normally open one lower down.
Anyhow watch this space….……
John

I think you're no the right track with the reed switch here. A Green Lane Section member ( I think it was Lawrence of Aylesbury) did repair his recently and described it to me. Fiddly but do-able with parts from Radio Spares type shops.

I’ll raise you a “Lawrence of Aylesbury” because I am in fact John of Wendover.
I shall write up my findings. I know, I should have photographed the key stages....
John( of Exeter now)

Today I decided to ride until I ran out of fuel once the low level light just came on.Thwarted at every stage by jammed vehicles on the Stoke Canon bridge, then a long tailback behind some kind of yellow thing,a digger or something. Then a learner, two separate sets of horses ( tickover only here) and finally a Sainsbury carbon footprint food van. Nevertheless I managed to get to Petton Cross at a distance of 21 miles before sputtering into a layby. A glug from my petrol can and back to Tiverton where put 7 litres of vodka in as no E5 visible.Stopped for delicacies at the Greek Bakery.No calories either.
Then stuck behind a Shearings coach which fortunately turned off before Bickleigh bridge.Just dodged the newly collapsing manhole cover in the centre of the road too.Put a further 12L of E5 back in Exeter. It is supposed to be a 22L tank so that seems about right.
John

It must be awful living in the Londoners playground. They pass here at 100 mph on their way to the Highlands.