Frequent tankfilling

[unimog]

The fuel gauge on my J20 -78 shows a little more than half tank even when the tank is filled with more than 60 litres. Any guidance to the problem, please?

[andy d]

Unimog, take the leads from the sending unit in the tank. turn on the ignition switch. touch one or the other leads to a known ground. the gauge should "peg" to full. if it does then the problem is with the sending unit and not the gauge. if you are very lucky, it could just be dirty connections at the sending unit. if not, its most likely the unit itself. the sending unit is a variable resistor whose value is determined by a float. either the float is stuck or the resistor is failing. im not familiar with the 78, but if the fuel pickup is integral with the sending unit as it on my 81 and up wags, i would make sure the replacement comes with a pickup screen.

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'88 gwag,pure stock

[unimog]

Tks andy d - I'll let you know in due course if your diagnosis is right. Presently it's minus 5 degr C and frosty and I just can't squeeze this rig into my garage.