Land-Rover 90 Hardtop. Factory-built 2.5ltr 200TDi. 93-94 vintage [but on an F-plate??]
This thing is driving me nuts and I must be overlooking something - but I can't see what.
This vehicle has just been rebuilt on to a new galvanized chassis. When the wiring loom was refitted; several things were amiss, including the fuel gauge, that had - apparently - worked normally before.
Fairly simple factory VDO gauge system. 12 volt feed to gauge; wire from gauge to sender; wire from sender to earth.
The gauge reads 3/4 full even with the sender at the bottom of its travel. Raise the arm even a little and the gauge reads max. Disconnect the sender and the gauge drops to zero.
Feed voltage at gauge 12.2v.
Resistance of sender [measured at gauge end - wire disconnected] 9.0 ohms tank full - 330.0 ohms empty.
Voltage on sender earth [all connected] 2 millivolts.
A new sender was tried even though I could find nothing wrong with the old one; exactly the same. I clipped a substitute cable between gauge and sender - exactly the same.
Even though I'd never seen one go faulty; it just had to be the PRC7313 gauge, as everything else checked out.....
Except it wasn't.... Exactly the same.
So what am I missing here? There's no voltage stabilizer and the similarly-fed ECT gauge reads correctly.
There is - allegedly - a "Low Fuel Warning Light Control Unit" connected to the link between gauge and sender - but that can't have any effect when I've got a direct link wired in. Although the low fuel light is wired to something; [not the spare terminal on the sender - which is a low tank level switch?] there's no sign of this mysterious unit.
Is it the wrong gauge? Where is this "Low-fuel Light" device hidden? Does anyone have the calibration resistance for the gauge?