Fuel sender fun

Hi guys, neither the fuel gauge nor the temp gauge on my series 3 88 (1978 I believe) work, however the speedo does; the fuel gauge reads empty even with about 3 in of fuel in the tank and the fuel warning light is on whilst it does this. I removed the fuel sender from the tank (it has 3 brass sections for connectors on top of it, with the third flattened one not connected to anything) and it appeared that the wire which connects to the plastic float was much too long and has been cut and cable-tied back together. I thought this was the end of the problem as it simply wasn't long enough to register the fuel in the bottom of the tank, however when I manually moved the sender to register 'full' the gauge only showed half full.... Have you guys got any idea as to whether this is a fault with the wrong sender unit being fitted, or if there is also a problem in the electrics not being compatible also. The Landy has a 12j engine fitted and is ex-military if that is of any importance!

Many thanks guys, any help would be appreciated!

I had trouble with mi gauges until I changed the alternator. It seemed the voltage was a little questionable.

I have a similar issue. Even if the tanks full it doesn't register. Once in a blue moon it does but only to a quarter full . Interested in any insight on this post. It's a pain having to estimate how much fuel there is.

Could it be the voltage regulator behind the dash? That often effects both fuel and temp re
reliability

The alternator is an interesting insight, hadn't even considered that as a possible issue. That said I assume the voltage regulator would be the thing to try first, does anyone have a part number/ link for this part? Or is it just a standard item?

I'm not sure if it's connected however I have a fuse which keeps blowing (second down of the four under the steering column), I've been through checking earths and have today pulled out and taped up about 5,metres of redundant wiring just left trailing by previous owners! Any possibility that these electrical problems are linked?

Cheers, Hamish

Sounds like voltage stabiliser because both gauges aren't working. However, the 12j metric head uses a different temp sender so you should check it actually has a series one. If that's not right, then maybe you just need a new fuel sender as well.
Have you tried earthing the wire to see if the gauge moves full scale?

I have just had a look at the temp sender, notmquite sure whether it is a series one fitted (I'll try to attach a photog), although the plastic cover over the connection was half melted through.... Perhaps the cause of the fuses blowing????
Cheers, Hamish

Don't sure that would blow a fuse as it doesn't seem to be touching anything. Anyway that's the wire you'd earth to check the gauge.
Can't tell if it's a series sender, you need to take it out and check the thread. 5/8 unf is series , something metric (m10 x 1.5?) is the later one

Edit. Looked at the photo again, I'd say that was a series sender because it's in the m16 hole so it's probably a 5/8 adapter.

I earthed the wired and when the ignition was turned there was a strange noise, sounded like the noise when the indicators are on, and the gauge remained unmoved. This seems to point towards the voltage regulator and some kind of a short/ earthing problem. If I order and fit a new voltage regulator, temp sender unit (the series vehicles) and a new fuel sender, should this cure the problem, or should i be going through and double checking eating points etc? Cheers, Hamish

W-Hamish said:

I earthed the wired and when the ignition was turned there was a strange noise, sounded like the noise when the indicators are on, and the gauge remained unmoved. This seems to point towards the voltage regulator and some kind of a short/ earthing problem. If I order and fit a new voltage regulator, temp sender unit (the series vehicles) and a new fuel sender, should this cure the problem, or should i be going through and double checking eating points etc? Cheers, Hamish

Click to expand...

Wiring will become a problem as it ages, check it, but be prepared to replace it ...

I knew that was coming, at least it's a shock I'm prepared to deal with lol