At 01:36 PM 11/6/03 +0000, Michael Hargreave Mawson wrote:
>
>My fuel gauge in my '77 Spitfire 1500 stopped working the other day, and
>I have just been trying to trace the fault. I am completely confused
>by my findings:
>
>With Ignition ON
>
>- Steady 12V across the wires at the sender
>
>- Fluctuating between 0.5V and 5.0V across the two wires at the gauge
>
>Can anyone suggest where on earth I should go from here? How do I test
>the sender? How can I test the gauge? HELP!
ATB,
For starters, I don't think you should have a steady 12V at the meter.
There is usually a voltage stablizer bolted to the back of either the
speedo or tach that is supposed to keep the voltage at about 10V.
Next, to these the gauge, simply remove the wire from the sending unit.
What does the gauge read? I don't remember - but it's supposed to read
either full or empty.
Next ground the wire - touch it to some good piece of metal. Now what does
it read? It should read the opposite of what it read when hanging in the
air.
If so, the the gauge and the connecting wires are good. I suspect this
is what you'll get.
Most of the time the problem is with the sending units. Not just for the
Spits but for most cars that are 20, 30 ... years old.
You will need to remove the sending unit from the tank. I suggest that
you try and empty the tank first.
Now if you reconnect the wire from the gauge to the sending unit, you will
probably need to add another wire to ground as most sending units get their
ground from the tank and the chassis.
With the sending unit hanging down, the gauge should read empty. As you
raise the float the gauge sure start moving up to full.
It's that simple. The 3 biggest problems that occur with the sending units
are:
1. the float - doesn't.
2. the wire resistor and wiper either break or corrode
both 1 & 2 will require replacement of the sending unit.
3. there is a bad ground to the sending unit. Simply add another ground
wire.
Hope this helps.
John
John T. Blair WA4OHZ email: jblair1948@cox.net
Va. Beach, Va (eBay id: zebra48-1)
Phone: (757) 495-8229
48 TR1800 48 #4 Midget 65 Morgan 4/4 Series V
75 Bricklin SV1 (#0887) 77 Spitfire 71 Saab Sonett III
65 Rambler Classic
Morgan: www.team.net/www/morgan
Bricklin: www.bricklin.org
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