67-72 Chevy Truck fuel gauge diagnostics 101

[jjzepplin]

Ok so I pulled out the cluster and checked the gauge removed. Tested perfect. Right up to full and no further.
Swapped out the printed circuit and checked again.
Right to the full mark and no further.
Cleaned all the harness contacts and plugged in.
Checked out good.
Almost YEEHHAAA!
Installed completely and checked. Goes over full (further than ever before).
Not much maybe 1/8 tank or so.
I guess I will drive around with a gas can till I can confirm
the levels. I know it is way full right now and has maybe 3-5 gallons before it should start registering anything on the gauge.
But it is NOT at the lower end of the gauge which is where it has spent most of it's years.
If I disconnect the sender wire it acts as it should.
Thank You so much and I hope this helps someone.
Will keep you all posted with long term results.
Happy Thanksgiving!

[TBONE1964]

Originally Posted by jjzepplin

Ok so I pulled out the cluster and checked the gauge removed. Tested perfect. Right up to full and no further.
Swapped out the printed circuit and checked again.
Right to the full mark and no further.
Cleaned all the harness contacts and plugged in.
Checked out good.
Almost YEEHHAAA!
Installed completely and checked. Goes over full (further than ever before).
Not much maybe 1/8 tank or so.
I guess I will drive around with a gas can till I can confirm
the levels. I know it is way full right now and has maybe 3-5 gallons before it should start registering anything on the gauge.
But it is NOT at the lower end of the gauge which is where it has spent most of it's years.
If I disconnect the sender wire it acts as it should.
Thank You so much and I hope this helps someone.
Will keep you all posted with long term results.
Happy Thanksgiving!

Sounds like the chapter is going to end soon. Go have some Turkey and relax.

You have a good Thanksgiving as well JJ,

Take care,
Tom

[jjzepplin]

Originally Posted by jjzepplin

Ok so I pulled out the cluster and checked the gauge removed. Tested perfect. Right up to full and no further.
Swapped out the printed circuit and checked again.
Right to the full mark and no further.
Cleaned all the harness contacts and plugged in.
Checked out good.
Almost YEEHHAAA!
Installed completely and checked. Goes over full (further than ever before).
Not much maybe 1/8 tank or so.
I guess I will drive around with a gas can till I can confirm
the levels. I know it is way full right now and has maybe 3-5 gallons before it should start registering anything on the gauge.
But it is NOT at the lower end of the gauge which is where it has spent most of it's years.
If I disconnect the sender wire it acts as it should.
Thank You so much and I hope this helps someone.
Will keep you all posted with long term results.
Happy Thanksgiving!

Update-so far gauge is functioning. Now on to that tachometer since you were so nice s to furnish some much needed parts. Thank You!