Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 Fuel gauge sender/rack

Leaking float? Has it soaked up some fuel so it weighs more and so sits lower in the tank?

Mine is now doing the same thing after 1,000 miles, very odd.

I think we just have to accept that the design of the M3W tanks and the behavior of that sender unit conspire to make reading fuel levels somewhat challenging. The 280mm sender helps, but doesn't cure the issue. So why not just use the motorcycle approach and rely on distance covered on the trip instead? I'll happily run to 250 miles of typical driving before filling. Over my trip to and from the TOTH last weekend I filled up at approx 170 miles (having had 0% showing for a decent while) and managed to squeeze no more than 30 litres in each time, proving I 'bottled' waaay too soon, again. But they were hard miles, so maybe 200 is a sensible limit to cover all occasions.....

Ditto. The soggy/leaking float theory might explain, but if so you would be hard put to reach 100% on gauge which I still regularly get after fill up.

If anyone has their boot pan removed can they check if there is room for the next size up 310mm sensor? Take measurement from sensor flange interface to bottom of tank allowing for thickness.

I've contacted VDO. I'll let you all know if and when they respond.

+1

I start looking to fill up at around 170 miles on the trip meter and will happily run to 220 - 230 before I start to worry.

A normal fill up is around 30 litres.

Another observation on this issue which I've noticed before but recently highlighted. After a long run yesterday I noted the fuel indication had dropped to below 25%. After an overnight rest, on start up it was indicating 41%.

I've suggested before fuel sloshing around the two tanks may explain. I also wondered if the ECU has any hand in reducing the reading during driving. Anyone else noticed this?

Mine does the same...

Same.
Its still highly inaccurate with the long sender , but in different ways !

While purchasing a 2014 Brooklands from Morgan West this weekend, I raised the question of the fuel with their mechanic.

He said (and this may be total fantasy) that the percentages shown on the gauge were not simply derived from the fuel sender in the tank. He argued that the output from the sender went through the ECU/computer that adjusted what is shown depending on the current engine load, rpm, etc. So, it is (in an odd way) doing a vague adjustment like some cars estimate miles to empty.

No question that he and the owner's manual say that at least, when the system reads 0/0 - there would be at least 3 gallons acting as a reserve. But still, that reading would be altered based on how you were driving.

It certainly did while we were driving and changed depending on how spirited we drove.

No clue how this really works....but, if true, would be affected by the accuracies of the inputs and any algorithm written to adjust the figures shown on the gauge.