Fuel Gauge Glitch

[Paul Roberts]

Fuel gauge is only indicating half full. Filled the tank but no change.
Checked voltage at both lives; both showing 11.35V
Earth is clean.

It had been working just fine.

Any and all thoughts welcomed and appreciated.

[Andrew S]

Sender unit?

[new to this]

Check the float inside the tank

dave

[Seaking]

Check the float inside the tank

dave

+1 hole in float

[Paul Roberts]

Thank you, all, for your help.
The consensus would appear to be a none floating float then.
I'll try to get it out over the (long) weekend.
This might be a bit of a challenge as we have friends arriving from Oz lia tomorrow afternoon - so I may have to drink wine instead.
Ho hum, it's not always easy is it

[Stagdad]

Check the gauge by shorting the wire that feeds it from the sender to ground, gauge should go to full.

[Paul Roberts]

Thanks, Steve. Will do first thing. Simples.

I was unsure of the potentiometer's operation but, from your advise, deduce that zero Ohms equals full tank.

Do you (or does anyone) happen to know what maximum (empty tank) resistance is, please?

[StagJonno]

Thanks, Steve. Will do first thing. Simples.

I was unsure of the potentiometer's operation but, from your advise, deduce that zero Ohms equals full tank.

Do you (or does anyone) happen to know what maximum (empty tank) resistance is, please?

Paul,
There was a similar thread on FB this past week where it was stated (reference Google search) that the resistances were 15 ohms full; 250 ohms empty.

Bit surprised at your measuring 11.5V as the fuel gauge is fed from the V regulator which is stated to provide 10V according to my wiring diagram (unless this is an error). I might check what wisdom the ROM holds in the morning.

Jonno

[Paul Roberts]

Ah; the thick plottens..... , as they say in all the best am-drams.

Thanks for the figures and insights, Jonno. Based on these I, too, will do a bit of sleuthing over the weekend.

[Staggard]

How did we ever fix the cars back in the day without all the electronic wiz kids. As said short out the gauge wire and check that it goes over to full if yes take out the sender unit and you will probably find that the float is leaking as they do this quite frequently. If that all check's out then its most likely the unit itself move the arm up and down the and check the reading on the gauge.

[mole42]

99.9% certain it's a hole in the float. 15 minute job, including unscrewing the boot trim to get the board out over the tank.

[wilf]

Double check the seal when refitting though. and fit a new one!

[Paul Roberts]

Once again; thanks to all for your insights.
I know it's easy to just whip out the sender unit from the tank but, as Wilf points out, a new seal is required when re-fitting.
I want to take my antipodean mate out, today, so didn't want to disturb the seal (it being a bank holiday weekend).
I'll check the gauge, by shorting the supply, but I'm happy to believe that the fault lies within the tank.
It's the down-time, waiting for parts delivery, that I dislike so much.
Ho hum - I'll check with nurse to see if she has any patience pills....

[mole42]

I have removed and refitted my sender three times and never changed the seal. It still doesn't leak.

Richard

[Paul Roberts]

Thanks, Richard. However, I have no idea of the age of mine.
Should I need a new sender unit - I'll get the complete kit and start from all new.