Lotus Elan and Lotus Elan Plus 2 Forums

I have a fuel gauge that reading very erratically. It was rebuilt last year by Nissongers. I am now on my second sending unit and I get the same erratic readings. The first sending unit was original to the car and the replacement sending unit seems to cause the same problem..

I have grounded the sending units and the gauge. yet the gauge still reads erratically - Any thoughts?

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What's the erratic behavior?

Are you seeing similar behavior on any other instruments? Have replaced the voltage regulator behind the dash at any point?

IMy car is an S1 so there is no voltage regulator. The other gauges are fine. Only fuel gauge is wonky, The erratic behavior is sometimes it reads full- even though the tank is not really full. Sometimes it reads accurately. The problem is that the needle just seems to move around randomly..

Sounds like there is something wrong inside the display gauge itself. Broken pivot or somesuch.

If the wire from the gauge to the sender was intermittently shorting to earth it could do this.If you disconnect the wire at the sender end do you ever get a reading on the gauge?
Check that the connection to the sender is not touching the flange of the sender

Ed

You might want to check the connection on the gauge too, the one on my S3 was loose causing exactly the same condition.

Hi,
These old gauges are quite complicated inside, two coils wound with very fine enamelled wire. I have found corrosion at the soldered connections, quite a tricky little job needing a steady hand an eyeglass and tweezers. See if you can get steady reading when the case is tapped using this test method.
http://mgaguru.com/mgtech/electric/fg_10.htm
Ron.