I bought a fuel gauge sender recently to replace one where the resistance track disintegrated cut through by the movement of the wiper arm after about 90000 miles. This new one has a linear wound resistor the wire is just wrapped round the former , while the old one had three different pitches of winding the resistance wire round the former. The old sender was pretty bad, started at 3/4 full for a full tank, but for all the time there was fuel in the tank, it still read something, despite dropping to the red zone after 100 miles, but then staying in the red zone for 100 miles, going 3 "steps" below zero after about 220 miles. The new JPM brand sender starts at 3/4 full as before but with the linear winding, the gauge drops pretty smoothly to zero at about 100 miles then vanishes off towards empty ... Which is annoying when the bus does about 220 miles on a tank of fuel. Anybody else seen this problem ?
Yep. On JP branded syncro senders. Another instance of a nearly but not quite copy from Denmark. They fill a hole...
All very complicated Mike ...if it wasn't for the bends in the filler neck a long thin piece of wood would give comfort and reasonable accuracy .
Not a new sender on our bus but it shows over full when full dramatically dropping over 100miles to under zero then your on your own guess work. the T3 shows over full when full unless you fill up at some filling stations where you can’t get enough in to fill the tank up fully for some bizarre reason. Then alarmingly drops to somewhere in the red zone where you can get anything from 80 quids worth in to brim it or sometimes it’s only £40 it makes no sense - probably due to atmospheric pressures - I don’t think these fuel gauge things will catch on….
I've often wondered if a linear potentiometer, like you would have as a volume or tone pot on a electric guitar, wired across the fuel guage would work, if you turned the pot to find the fuel gauge full and empty point then connect the float arm to work between those two points !!! Might be worth experimenting with !!
That might work but a trimpot is usually set to a value whereas a pot is more used for variable value that's being changed constantly
The originals were wrapped around a shaped former to account for the paddle arc and the wires were equi-distant throughout and close together making a smoother surface that didn't wear out so quickly. Cheap and cheerful now.
I use a fibreglass top sail batten on my boat to measure diesel depth, I used to use bamboo or wooden dowels until I lost the end of the stick a few times .. And I gave up on bothering with red diesel years back. It doesnt use enough to bother with the different price . To be honest, the best fuel gauge I have come across was a pressure sensor at the bottom of the fuel tank, and a software tool that you put in the profile of the tank. The pressure is proportional to the depth , the fuel left is the integral of the cross section areas of the tank. I have also come across one that used an ultrasonic distance measuring system to measure the distance to the top of the fuel, but on that one, having a single cylinder diesel generator hammering away caused so much vibration, the distance measuring went haywire.
Red diesel is to be no more soon i believe . Diesel as altered in viscosity over the years . The old Derv as was called in 60's was thicker . Old diesel fuel pumps on wagons needed the thicker diesel to lubricate the internals ,they can wear out quicker so i was told with the newer diesel . On my old Foden the mini crankshaft on the CAV inline pump had oil fed lube but the barrels and plungers benefited from the old thicker fuel .
I spoke to some guys from VDO at a show, they said that if there became a need for them they would produce a sender and matching gauge with no need for the vibrator. About time we all started emailing them.
And the fuel gauge on the tank was all mechanical just a simple dial no electrics ...you just had to get out your cab and have a butchers . And if the gauge didn't work just open the filler and look down with a torch or stick .
The Beetle fuel gauges are all mechanical, certainly they are before '68, not certain precisely of the exact date, anyway just a float and a Bowden cable to the gauge in the cab, much less to go wrong. Prior to that it was a reserve lever and that was your lot. Owning both vehicles shows how much thought Ferdinand and co put into the Beetle's design and how many odd design decisions, by comparison, there are in the Bay.
The differences between the prototype and the Late Bay are partly driven by cost down. So a quality moving coil gauge was replaced with a spring loaded resistance wire with a lever to multiply the movement. A long variable resistor in the tank was replaced by levers and a smaller resistor track .. and so on ..
This is my old one off a 79. It's shaped with a waist in the middle but the wiring also varies in spacing. I had considered getting some nichrome wire and redoing it. It's got notches to guide the wire spacing, but even so my eyesight's not that good. Only about 40 turns though.
