fuel sender

[toby noble]

How do I check whether my 280i fuel sender unit is functioning? The fuel gauge is dead but worked fine before a four month restoration.

I really don't want to have to pull it out of the tank if it's not necessary...

Just bought a multimeter but I'm still learning how to drive it....

Toby

[sevans]

Take the two wires off the sender. With them removed the gauge should be at one end of the scale then short them together and it should move to the other end (can't remember which way round it is). If that works OK then the problem will be in the sender, maybe a stuck float.
It's not to difficult to remove the sender if necessary. I assume there is enough petrol in the tank to lift the float. It's not the most accurate setup and it maybe that the tanks need to be reasonably full to give a reading.

[wedg1e]

I seem to vaguely recall that the sender on my Tasmin was earthed to the tank, and the tank to the chassis with an earth strap that corroded away. Once that happened, the gauge packed in. If you've just had a refurb, is it possible that the earth is missing in a similar way?

Ian

[danny hoffman]

You can change the sender without removing the tank

[sevans]

I have an 83 Tasmin with trailing arm suspension and you can replace the sender without removing the tank.
Not sure about the earth straps, mine has never had any and the sender has always worked OK. I thought it was just a variable resistor between the two connections.
I would do what I suggested earlier before taking out the sender, it could be a wiring fault.

[Toby Noble]

Okay, I've checked the contacts and I notice that the needle moves slowly from below empty to empty when I turn on the ignition. Definitely a circuit there.

Looks like I'll have to remove the sender, but I'm concerned about getting it to seal again afterwards. Not likely to find a replacement gasket down under though....I could do without another fuel leak.

[andymadmak]

You can shoot me for this if you want to, and I know it's a really silly question, but, you do have some fuel in it , don't you?

Andy 400se,

[Toby Noble]

Christ, I knew I'd forgotten something.........

Sorry to bother you.




Um yes, I checked that. I keep it topped up 'cos the speedo's knackered, not a good combination.

BTW

[andymadmak]

Thought you'd have thatangle covered!

If the guage is moving a bit, it still sounds like a bad earth/connector. The only other thing I can think of is that perhaps the float arm got damaged/stuck when the tank was out?
Andy 400se

[danny hoffman]

Have you shorted the wire on the sender unit to a good earth as previously suggested?

Re the gasket - you can buy a sheet of gasket material and make one your self, should take too long.

Danny

[Toby Noble]

Okay. On the weekend I did what was suhggested, i.e. shorted the wires that attach to the sender. The gauge went from empty to full... If , as suggested, that means my sender is duff, I need a new one. Are they a Ford part and do they have part numbers?

Also. if that's a cork gasket it's gone awfully black...looked more like silastic or similar. Not looking forward to getting that to seal again.

[ANDYM]

Having done some restoration on my 400 when I drained the tanks the gauge was at the bottom of red yet there was still close to 10 litres of fuel in the tanks! It took me 3 visits to the petrol station with my can before the gauge moved to the bottom of the red again, bearing this in mind have you got around 10 litres of fuel in the tanks? Not sure if 400 tanks are larger though but it might be worth trying.
Andy.