The old Fuel Gauge saga!

Hi all,

My truck - the antithesis to Christine!
No matter how much I try to fix it - it fights back!
1987 350 R10

I have replaced fuel pump and sender (as it needed a pump - the sender was a bonus I had hoped would fix the fuel gauge too).
The fuel gauge would read all over the place - forever changing during any trip.
PCB has continuity.
Earths all good.
I fitted a new (Classic Industries) gauge - with a known empty fuel tank.
Put in approx. 10 gallons of fuel - gauge read just over half a tank.
Happy man.
As I used the truck, the gauge dropped as I would expect(!), topped up 5 gallons or so - gauge went up.
Gauge was then dropping way slower than I would expect with use (to just under half a tank) - so put in another 10 gallons - gauge did not move back up.
It has continued to drop away to quarter a tank. I have just filled it up - and the gauge has still not risen - it is sat still on the quarter tank.

So - new sender, new gauge, good wiring - the gauge only seems to want to drop - not rise.
ANY clues - ideas what to check?!

Cheers,
Keith

Unfortunately you have to check all components again.
Check ground.
Check if the gauge is working as it should.
Check resistance of sending unit. Maybe the float of your sending unit is sticking/not moving free.
There's no guarantee that new parts work as they should these days.

Do you have only one tank and one in-tank fuel pump, with no 6 port fuel solenoid for two tanks?

75gmck25 said:

Do you have only one tank and one in-tank fuel pump, with no 6 port fuel solenoid for two tanks?

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I assumed one as Keith wrote he replaced one sending unit.

Hi guys,

I have the twin tanks - single pump in each.
I am running the left hand tank only (new pump and sender)
Will go back checking everything.

Don't know if this suggest anything, but the gauge does not move at all - not even twitch, when I switch from left to right tank.

Replace the printed circuit on the back of the gauge cluster. I replaced mine when I built a factory tach cluster for my truck. I was pleasantly surprised afterwards when all my lighting and wonky accessory gauge issues were resolved as well.

UKSquarebody said:

Don't know if this suggest anything, but the gauge does not move at all - not even twitch, when I switch from left to right tank.

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ali_c20 said:

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Great - thank you.