[Mgs] 1974 MGB fuel gauge problem

[Paul Hunt]

Intermittent low or non-existent readings are usually caused by bad
connections somewhere, either that or the sender is sticking.  If you bridge
the green/black and black connections on the *spades* of the sender and the
gauge shoots up then it is the sender.

If that doesn't do it bridge the connectors on the wires this time, and if it
shoots up then it is the connections between the wires and the sender.

If that doesn't do it get a known good ground from somewhere and connect that
to the green/black, and if the gauge shoots up then it is a bad ground, which
comes from a number plate bolt in the boot.

If that doesn't do it connect a known good ground to both sides of the
green/black bullet connector in the mass by the fusebox.  If one side does it
but not the other than that connector is at fault.

If still no go it is a problem with the gauge or stabiliser connections, but
the foregoing are more likely, so I'll stop there for the moment.

PaulH.


----- Original Message -----
  From: wkilleffer at comcast.net
  To: mgs at autox.team.net
  Sent: Sunday, June 08, 2008 4:35 PM
  Subject: [Mgs] 1974 MGB fuel gauge problem


  Hey Everyone,

  A couple of years ago, I noticed that the temp gauge and fuel gauge on my
1974 MGB were reading quite high. Temp gauge was pegging the H, and the fuel
gauge couldn't be trusted. I learned about the voltage stabilizer behind the
dashboard, and discovered that it had been bypassed. I hooked the gauges up to
it, and they worked properly. Both seemed reasonably accurate.

  Now, over the past couple of months, the fuel gauge has developed some kind
of fault. Most of the time, the needle barely moves away from the E. It moves
just enough to show that it's responding to electrical input, but no more. Now
that the weather is getting hotter, I've noticed something odd. The fuel gauge
will start working and give what appears to be an accurate reading. I reset
the trip odo every time I fill the tank, so based on that mileage, the gauge
is true. It will work for a few minutes, then it will go back down to near E.

  I replaced the sending unit in the tank about 7 years ago. The temp gauge
never has a problem.

  Also, this doesn't happen every day.

  What are some possible fuel gauge faults that could cause this?

  Thank you,
  -Bill
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