Fuel Gauge Issue Need Advice

[Tire Guy]

The fuel gauge pegs to the left when the ignition is on. I have worked through the wiring and everything seems to be in order.

The tank and sending unit is brand new.(which I am glad of)

Is the issue that the new sending unit will not work with the original gauge or am I missing something?

The wiring on this truck is going to be an ongoing issue.

Thanks.

[OrrieG]

Sounds like you are using a new 90 ohm sender with the original gauge set up for 30 ohm. Lots of places on line sell the 30 sender to fit in new tanks. Bummer if you have to pull the bed to replace.

[Tire Guy]

Originally Posted by OrrieG

Sounds like you are using a new 90 ohm sender with the original gauge set up for 30 ohm. Lots of places on line sell the 30 sender to fit in new tanks. Bummer if you have to pull the bed to replace.

Nope, the tank is still behind the seat. Then options are:
Replace the sender
Replace the gauge
Rebuild/replace the entire gauge cluster....

How do I make sure the sender is 90 ohm?

[dwcsr]

Or just put a 47 ohm resistor in the wire from the sender to the gauge.

[Tire Guy]

Originally Posted by dwcsr

Or just put a 47 ohm resistor in the wire from the sender to the gauge.

That sounds like a great short term solution until I do the whole gauge cluster. Thanks.

[_Ogre]

if you bought a replacement tank and sender it will be 30 ohm
E with key off and F with key on means the gauge works
have you modified the wiring at all?

probably the sending wire between the gauge and the sending unit is grounded
remove the wire from the sending unit, the gauge should go to E
if not start wiggling the wire the gauge should start jumping around
if so replace the wire between the gauge and sender

[Tire Guy]

Originally Posted by _Ogre

if you bought a replacement tank and sender it will be 30 ohm
E with key off and F with key on means the gauge works
have you modified the wiring at all?

probably the sending wire between the gauge and the sending unit is grounded
remove the wire from the sending unit, the gauge should go to E
if not start wiggling the wire the gauge should start jumping around
if so replace the wire between the gauge and sender

I bought it this way so no telling what was installed.
Full left when off
Full left when turned on but does move like it has power.
Connections on unit and gauge are good.
When removing ground from sender it goes full right.

Thought?
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[Old Crow]

Full left hooked up, full right disconnected...bad or incorrect sender.

[_Ogre]

pics would help

[Tire Guy]

Originally Posted by _Ogre

pics would help

I'm not sure what to post pictures off.

Worked on it today. Ran new wire to the sending unit. No change. I'll try the resistor once I get one. Oh well.

The wiring on this truck will be the death of me....?

[dwcsr]

I have seen where they forgot to put a insulator washer under the center nut on the sender wire terminal and it acted as a ground.

[Donaldo]

Originally Posted by dwcsr

I have seen where they forgot to put a insulator washer under the center nut on the sender wire terminal and it acted as a ground.

It sounds like a dead short at the sending unit to me.

[_Ogre]

Originally Posted by Tire Guy

I bought it this way so no telling what was installed.
Full left when off
Full left when turned on but does move like it has power.
Connections on unit and gauge are good.
When removing ground from sender it goes full right.

if i'm reading this correctly
key off shows empty
key on still shows empty, but it moves a bit
sender disconnected the gauge goes to full???

that makes no sense
i'm shooting from the hip here... open discussion for all members to see if my ideas are right

if the tank is full, is it possible that the gauge is wired backwards?
key off- no power, gauge is off and goes to empty
key on- gauge wired backwards empty is the new full
sender wire removed- gauge wired backwards full is the new empty

just my thoughts, wait for someone to chime in before you remove your cluster

[_Ogre]

a pic of your sender would show that it is wired correctly

[Tire Guy]

Originally Posted by _Ogre

if i'm reading this correctly
key off shows empty
key on still shows empty, but it moves a bit
sender disconnected the gauge goes to full???

that makes no sense
i'm shooting from the hip here... open discussion for all members to see if my ideas are right

if the tank is full, is it possible that the gauge is wired backwards?
key off- no power, gauge is off and goes to empty
key on- gauge wired backwards empty is the new full
sender wire removed- gauge wired backwards full is the new empty

just my thoughts, wait for someone to chime in before you remove your cluster

Goes full right with the key on and the ground disconnected. Here is the pic of the sending unit ground on left.

[OrrieG]

I don't see an insulating (fiber) washer under the brown connector.

[Stepside Jim]

Looks like a power and a ground, my concern is what would be the power wire, it looks like it doesn't have a insulating washer and going directly to ground.

[Tire Guy]

Originally Posted by Stepside Jim

Looks like a power and a ground, my concern is what would be the power wire, it looks like it doesn't have a insulating washer and going directly to ground.

Let me coble one together.

[TransMan1972]

I would use a different lug on the brown wire as well, so its insulated closer to the connection point... also turn the lug over so the lug can not touch the tank or any part to ground...insure you use the proper crimper tool for a insulated lug...

[Tire Guy]

Originally Posted by TransMan1972

I would use a different lug on the brown wire as well, so its insulated closer to the connection point... also turn the lug over so the lug can not touch the tank or any part to ground...insure you use the proper crimper tool for a insulated lug...

WE HAVE A WINNER!!!



That did it!

But down a washer to keep the sender up.
Insulated with double layer of quality black tape. (I'll get a proper felt washer later)
New connector with wire turned up.
Tightened down the nut and TA DA!
I have a half of tank of gas. WHOO HOO!

I can't thank you guys enough. You guys rock!

Tomorrow I'll start a thread on the tail lights which are in even worse electrical shape.

Thanks again. Happy 4th of July.

[_Ogre]

glad it's working
pictures ALWAYS help

[Tire Guy]

Originally Posted by _Ogre

glad it's working
pictures ALWAYS help

When you're right you're right! Thanks Ogre.
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