![]() |
![]() |
#1 |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
fuel gauge
fuel gauge on 72 k20 not working. ok when parked in fall. where to start. all other gauges appear ok
Thanks |
![]() |
![]() |
![]() |
#2 |
Senior Member
![]() Join Date: Nov 2013
Location: East Tennessee
Posts: 2,116
|
Re: fuel gauge
__________________
1967 C10 Step side 1968 C10 Step side 1970 Chevrolet K/5 Blazer 1972 Chevrolet K/5 Blazer ............. ![]() |
![]() |
![]() |
![]() |
#3 |
Registered User
Join Date: Jul 2008
Location: Eastern Oregon
Posts: 2,275
|
Re: fuel gauge
I had an inoperative fuel gauge. I replaced the sending unit, rechecked all the continuity. Eventually I determined that the needle was just stuck in place. Had the cluster out and just moved it a bit with my finger. Original gauge still works fine. Can’t say that about a lot of the new Chinese knockoffs.
__________________
71 C-20 07 Magnum RT AWD |
![]() |
![]() |
![]() |
#4 |
Active Member
![]() Join Date: Jan 2015
Location: central oregon
Posts: 177
|
Re: fuel gauge
Take the sending unit wire of sender, ground it out. If gauge moves its the sender. This was my problem ha
|
![]() |
![]() |
![]() |
#5 |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
Re: fuel gauge
thanks for replies. got some work to do. i have a relocated tank under bed and it may be a process to get to wire
|
![]() |
![]() |
![]() |
#6 | |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
Re: fuel gauge
Quote:
|
|
![]() |
![]() |
![]() |
#7 |
All stock and staying that way
![]() Join Date: Jul 2003
Location: Elkland, PA
Posts: 1,351
|
![]()
Make sure the tank is grounded to the chassis.
__________________
1970 K/5 Blazer CST 4WD, Bronze, 93k ACT. miles, 350, 4 speed, positraction, 16.5" x 8.25" wheel option, tilt, tach, vacuum, AM/FM, manual throttle...Dad ordered and purchased new 4/70. Currently frame off restoration in progress... ![]() 1972 Cheyenne Super 20 2WD, DK Blue/White, 90K ACT. miles, 402, TH400, 4.10 open, tilt, tach, vacuum, A/C, AM/FM, manual throttle.. A mostly original paint never rusted Texas survivor... ![]() 2017 Sierra 1500 SLT 4WD, Black, 41k miles, 5.3, 6L80E, 3.42 LS, 20" polished wheels, everything but moonroof and 6.2... 2019 Canyon SLT 4WD, White, 60k miles, 3.6, 8L45, 3.23 LS, 18" wheels |
![]() |
![]() |
![]() |
#8 |
Senior Member
![]() ![]() Join Date: Jan 2005
Location: CA
Posts: 5,346
|
Re: fuel gauge
Initially you could just access the tan sender wire where it plugs into the fuse panel under the dash. Unplug it there and ground the fuse panel Fuel Gauge terminal to see if the gauge moves to Empty.
|
![]() |
![]() |
![]() |
#9 |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
Re: fuel gauge
I haven't been able to locate the wire at fuse panel
|
![]() |
![]() |
![]() |
#10 |
Senior Member
![]() ![]() Join Date: Jan 2005
Location: CA
Posts: 5,346
|
Re: fuel gauge
It should be a tan wire that plugs in at the end of the fuse panel.
|
![]() |
![]() |
![]() |
#11 |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
Re: fuel gauge
thanks for the picture locate, I will check it out
|
![]() |
![]() |
![]() |
#12 |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
Re: fuel gauge
the gauge is registering E now. when grounding out would gauge peg hard to left (empty side)
|
![]() |
![]() |
![]() |
#13 |
Senior Member
![]() ![]() Join Date: Jan 2005
Location: CA
Posts: 5,346
|
Re: fuel gauge
Disconnecting the tan wire from the fuse panel with the ignition on should cause the needle to move way past Full to around the 3 o'clock position. Then grounding the fuse panel terminal should move the needle back to Empty. If it acts that way, then your gauge is likely good.
|
![]() |
![]() |
![]() |
#14 |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
Re: fuel gauge
gauge cks good. thanks for the pic.
guess i need to make sure wire from fuse panel to tank is good. tank and sender not very old. I'm hearing alot of parts we are getting are from China and not good quality |
![]() |
![]() |
![]() |
#15 |
Active Member
![]() Join Date: Jan 2015
Location: central oregon
Posts: 177
|
Re: fuel gauge
Run a cheap piece of wire to sender to try or just take the 2 minutes and remove the sender to test
|
![]() |
![]() |
![]() |
#16 |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
Re: fuel gauge
looks like wire from fuse pnl to sender is good. it would be a quick job to remove sender if it wasn't located on top of fuel tank and pu bed sitting over the relocated fuel tank was removed
|
![]() |
![]() |
![]() |
#17 |
Senior Member
![]() ![]() Join Date: Jan 2005
Location: CA
Posts: 5,346
|
Re: fuel gauge
Since the gauge returns to Empty when you have the sender wire connected, that tells me the sender wire is providing a path to ground. Your tank is likely adequately grounded. My guess, as others have already mentioned, is that your sender float has filled with gas and has sunk to the bottom of the tank.
|
![]() |
![]() |
![]() |
#18 |
Registered User
Join Date: Feb 2022
Location: Ca
Posts: 419
|
Re: fuel gauge
Grounding the wire at or just in front of sender would have eliminated a few steps. I agree. You have a bad sender. Either a result of a faulty float or potentiometer in the sender. Either requires pulling the sender to verify. You can put a ohm meter on the sender. Swinging the float arm should move your meter from 0 to 90 ohms.
|
![]() |
![]() |
![]() |
#19 |
Senior Member
![]() Join Date: Oct 2015
Location: Williamston, Mi
Posts: 879
|
Re: fuel gauge
I put a new suburban tank under the back of my truck 3 years ago, last summer after final assembly I got the truck out and was on empty all the time. Pulled the sending unit out and the float was full of gas. Bought a new plastic float for a jeep as recommended by folks here, solved my problem.
|
![]() |
![]() |
![]() |
#20 |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
Re: fuel gauge
so maybe can repair with a new float
|
![]() |
![]() |
![]() |
#21 |
Senior Member
![]() Join Date: Feb 2002
Location: Tucson, AZ USA
Posts: 7,098
|
Re: fuel gauge
The OEM replacement type brass ''football'' floats tend to leak due to bad soldering factory practices. Better to use the plastic Jeep float.
P/N: Omix-Ada......17729.01....$7.95 from Amazon. Exact fit. My OER float had sunk, and that fixed it.
__________________
Every 25 years I like to rebuild that 292, whether it needs it or not. |
![]() |
![]() |
![]() |
#22 |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
Re: fuel gauge
good info
thanks for the help |
![]() |
![]() |
![]() |
#23 |
Registered User
Join Date: Nov 2018
Location: Tieton,WA
Posts: 48
|
Re: fuel gauge
finally removed rear mount tank (purchased from Brothers) unit had failed from poor soldering from factory it appears. Quality of complete fuel sender unit kinda looks questionable. Anyone know of where to get a complete quality replacement unit
Thanks |
![]() |
![]() |
![]() |
#24 | |
Senior Member
![]() Join Date: Feb 2009
Location: Northern Nevada
Posts: 7,156
|
Re: fuel gauge
Quote:
__________________
Tony 71 Custom Deluxe, SWB, 2WD, 402, A/C. I developed an assm. guide "kit" for restoring the truck from ground up. With assys, the guide accts for 1000s details, OEM identifications & part numbers, written in short order. 700+ images of assm., illust., charts, and points of interest. Much of the info. applies to all 67-72 GM trucks, and to a lessor degree all 67-72 GM vehicles. My build thread, and more on the guide https://67-72chevytrucks.com/vboard/...d.php?t=730025 |
|
![]() |
![]() |
![]() |
#25 |
Registered User
Join Date: Dec 2017
Location: Elkhart, Texas
Posts: 1,573
|
Re: fuel gauge
Six years ago when I bought my '71, the fuel gauge did not work.. The brass float had rotted out and sunk to the bottom. I installed an LMC sending unit and the gauge worked perfectly. 3 - 4 months later, the gauge quit working again. The solder joint on the float had failed, the float filled with gas and subsequently sunk. LMC provided me with a replacement sending unit. A few weeks later it failed. I returned the sending unit and LMC issued a refund. I bought a sending unit from Classic Industries, and examined the sending unit to see if I could determine the reason for the solder failure.. The float fitted tight in the "loop" of the arm. I removed the float and opened the loop enough that the float was loose but well captured.. This all happened in 2018.. Today that same float/sending unit is in my truck, working perfectly..
As you know, solder doesn't have much structural strength. I believe the loop fits the float too tightly, causing stress on the solder joint, and it will eventually fail. Loosen the loop , releasing that tension and the premature float failure issue is resolved. |
![]() |
![]() |
![]() |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|