fuel guage reads full with the ignition off 63 ch tk

[jonzcustomshop]

I've been trying to get the fuel gauge to work in my 63 chevy truck.
I tested everything, and found that the sending unit was not working.
I pulled the sender out of the tank. the metal strap that goes from the sending unit to the connection was broken at the top of the connection. I soldered this connection back together.

the guage now works, but does 2 things that are not normal.

1)the gauge needle moves to past full when the ignition is off. when you turn the ignition on it moves back to the level of gas I have in the tank (1/8). I filled the tank a little and the reading increased, so it seems like the sender is working.

2)while driving the needle cycles from the fuel level to empty and back, sometimes it goes smooth, sometimes it jumps, and sometimes it just stays put at the 1/8 mark.

I also have what seems to be a good sender out of a 66 chevy truck (on a bench test it moved the guage), but I had heard that the ohms changed from 0-30, to 0-90 at gm in 65... I don't know if this is true for this truck, lmc truck just lists one part # for a sender for a 60-66 chevy/gmc truck.

any help or pointer would be appreciated!

*** a guy on the hamb mentioned that the sender might be worn, and that is why I am getting a sporadic reading, I am going to try the sender out of the 66, but I am still unsure why the guage moves to full with the ignition off...

[Rich 5150 69]

Sounds as if you have a 90 ohm sender with a 30 ohm gauge, that is what I have, it reads the same just drops a lot faster so that when it reads empty I actually have 1/2 tank, the jumping around confuses me tho as if the gauge is sticking or the float is sticking. Mine also reads full with ig off, correct when full.

[jonzcustomshop]

you know that might have happened...I did change the guage during this whole process, and right now it has a 61 guage..maybe I will change it back , the 61 and the 63 guages were both good, I had already switched them, and didn't switch them back.
anyone know if gm switched the ohm reading between 60-66?

[aerotruk63]

Spectra Premium one of our suppliers lists their 1960-66 replacement sending units as FG119A ( google part number for suppliers ). In the notes conotation: 0-27 Ohms. Have to go out to the trailer to check GM parts book.
My Boss who's been around cars 40+ years told me on the back of the dash is a Voltage Limiter that controls the sway movement of the gas gauge. Looks like a inline coiled spring he says.
P.S. he thinks were all obsessed.

[hossmann]

my 66 gauge was a 0-30 and my sender was a 0-90 so i bought a cheap gauge from the parts store and put it in till i can find a 0-30 sender to replace the old one

[aerotruk63]

[jonzcustomshop]

Originally Posted by aerotruk63

Spectra Premium one of our suppliers lists their 1960-66 replacement sending units as FG119A ( google part number for suppliers ). In the notes conotation: 0-27 Ohms. Have to go out to the trailer to check GM parts book.
My Boss who's been around cars 40+ years told me on the back of the dash is a Voltage Limiter that controls the sway movement of the gas gauge. Looks like a inline coiled spring he says.
P.S. he thinks were all obsessed.

do you think I could bring that # to napa and order one?
never mind..saw the google, would be cheaper from lmc truck, and cheaper yet to just fill up the tank and keep it that way....

[jonzcustomshop]

oh and how about his... I dropped the #@&*@$@^@&&@*@###%***!**^ good 66 sender on the floor last night , and cracked the float, AND the stupid connecting(electrical) strap broke just like the one on the 63!!! %%##**!

[aerotruk63]

But you have 17 trucks!

[jonzcustomshop]

yeah..but not as many good tanks-haha + 3 are my drivers, 3 are for sure bad, 3 more are running trucks that I don't want to part out, and 3 have no tank... lets see that leaves me with 5 more options to check...of those 5 I think only 2 have a gas cap...

[aerotruk63]

All it takes is one!

[jonzcustomshop]

I know, I know...
hey does your 63's guage go to full with the ignition off?
I am now thinking that the 63 k20 does it as well

[aerotruk63]

I'll have to check.