Fuel gauge reading wrong

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I've had other older vehicles that had an IVR...(instrument voltage regulator) in the dash that necks down the voltage to about 5 volts before reaching the gauges. I guess the coiled wires inside the fuel gauge and or water gauge act to do this and there is no central IVR???
 
I’m having a similar issue, but my gauge reads full and goes to empty, then I fill up and it only takes 13gals to fill up. I’ve replaced the sender, but it looked like the PO did the same cause the one I pulled out was brand new. I just replaced the gauge with one from eBay. In short, I’ve just been throwing parts at the problem. It also looks like the PO cut the wiring harness in the quarter panel and used scotch lock to reconnect everything. I haven’t been able to do anything about that yet because I’ll likely need to pull the tank and get access to everything to rerun the wires.

With that all being said, I have a spare fuel level sender and a spare gauge cluster laying around now. I’ll hook everything up to my DC bench power supply and try to get some readings and report back when I get a chance.
 
There is a connection between the temp gauge and the fuel gauge. This thread points to cleaning contacts in the temp gauge to fix faulty fuel gauge. Is your temp gauge bouncing or reading low?

forum.ih8mud.com

Temp Sending Unit?

forum.ih8mud.com forum.ih8mud.com
 
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@FJ60Seth that gauge avail still? I’d take it if no one has.
 
poptart said:
I’m having a similar issue, but my gauge reads full and goes to empty, then I fill up and it only takes 13gals to fill up. I’ve replaced the sender, but it looked like the PO did the same cause the one I pulled out was brand new. I just replaced the gauge with one from eBay. In short, I’ve just been throwing parts at the problem. It also looks like the PO cut the wiring harness in the quarter panel and used scotch lock to reconnect everything. I haven’t been able to do anything about that yet because I’ll likely need to pull the tank and get access to everything to rerun the wires.

With that all being said, I have a spare fuel level sender and a spare gauge cluster laying around now. I’ll hook everything up to my DC bench power supply and try to get some readings and report back when I get a chance.
Click to expand...
I drained my tank and dropped it about an inch. That was enough clearance to snake a new wire in.
 
g-man said:
is this a known working gauge?
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I can’t say for certain, so no. It was in the car previously and would read full at full but it would read empty with only 13 gallons used. Still sorting everything out.
 
Fyi, on my working fuel gauge and wiring I measured voltage on pin#3 to be 11.6 V, If this were off I think your temp gauge would be off as well as this voltage flows thru the temp gauge first. I suspect you may find your problem on the ground side of the wiring, from pin#13 back to the sender.
 
So quick update. I am convinced that the FSM is wrong with the 55 ohm spec between posts 1&2 (as indicated in the FSM) . There are now too many examples in this thread showing the resistance to be 25 ohms to ignore. My original gauge, @g-man @poptart gauges, and now a donor gauge that I received and tested today (was known to be working when it was pulled). I just filled up so it reads perfectly—I just filled up and have driven about 15 miles. I’ll be reporting back as I go through the this tank of gas and the readings on the gauge.

Donor gauge connected to my truck today

9F32CC14-0FDE-44E1-ACE4-6EC94810A119.jpeg


Resistance test on donor gauge

6AD269A5-D396-46C9-A922-30F82F1607CF.jpeg


So what is the problem with my original gauge? Maybe the voltage regulator in the gauge? Interestingly though is where the donor gauge needle rests on the “E” when the key is off (which looks to be the correct way), my original gauge needle falls all the way to the bottom of the gauge, well below the “E”.
 
Quick aside. The retainers on my cluster were cracked—we have found a great way to fix them—Lego. Fortunately my son is a master builder so we’ve got a bunch.

BTW, MEK works much better then super glue—it “welds” the plastic together. I have found it to be quite strong—for plastic.

Broken, cracked retainers cleaned up with dremel

0603F126-9A3F-46F3-B54E-C391A7176E74.jpeg

1BC4DFBC-D6FE-4457-BCD3-23F666FAA2D3.jpeg


Lego attached with MEK. Just need to let it dry then drill the appropriate size hole.
4724C9B3-6F0B-461B-9F94-E9FCDE886179.jpeg

A2599E92-18F5-4B6F-AA30-3ABFFEC0D960.jpeg

D8FF928B-8730-4131-8EBE-23C395BC75F4.jpeg


Have fun. You’re kids won’t miss a few Lego missing!!
 
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MadMace said:
So quick update. I am convinced that the FSM is wrong with the 55 ohm spec between posts 1&2 (as indicated in the FSM) . There are now too many examples in this thread showing the resistance to be 25 ohms to ignore. My original gauge, @g-man @poptart gauges, and now a donor gauge that I received and tested today (was known to be working when it was pulled). I just filled up so it reads perfectly—I just filled up and have driven about 15 miles. I’ll be reporting back as I go through the this tank of gas and the readings on the gauge.

Donor gauge connected to my truck today

View attachment 2603550

Resistance test on donor gauge

View attachment 2603551

So what is the problem with my original gauge? Maybe the voltage regulator in the gauge? Interestingly though is where the donor gauge needle rests on the “E” when the key is off (which looks to be the correct way), my original gauge needle falls all the way to the bottom of the gauge, well below the “E”.
Click to expand...
I tried getting my spare fuel gauge and sender to work with my test bench dc power power supply. Well, it didn’t go well. I think one of the alligator clips slipped at some point and I got some smoke from somewhere. But yeah still 25ohms but I could not get the gauge to go over 1/2 tank. Which is weird cause this was the gauge that never read right except at full. Idk if the gauge I swapped in works yet. Seems to not be drop as fast as before but we’ll see when I go through a tank or two
 
MadMace said:
Quick aside. The retainers on my cluster were cracked—we have found a great way to fix them—Lego. Fortunately my some is a master builder so we’ve got a bunch.

BTW, MEK works much better then super glue—it “welds” the plastic together. I have found it to be quite strong—for plastic.

Broken, cracked retainers cleaned up with dremel

View attachment 2603563
View attachment 2603564

Lego attached with MEK. Just need to let it dry then drill the appropriate size hole.
View attachment 2603566
View attachment 2603565
View attachment 2603573

Have fun. You’re kids won’t miss a few Lego missing!!
Click to expand...
I had the same issue but I had most of the plastic chunks that broke off. I ordered a new dash from Toyota through the local dealer, 62 not a 60
 
g-man said:
@MadMace... are those lego repairs to your original piece? What kind of shape is the piece that you bought. PM me if you are interested in selling it. Also glad to hear your new fuel gauge is working for you.
Click to expand...

Yes, original one. I was planning on using the one you gave me the lead on earlier in the thread because of the breaks but might be able to stick with this one as the repairs look strong. I'm going to install my original (repaired) one this weekend to see how it holds up. I can shoot you some pictures of the other one later today if you want.
 
poptart said:
I’m having a similar issue, but my gauge reads full and goes to empty, then I fill up and it only takes 13gals to fill up. I’ve replaced the sender, but it looked like the PO did the same cause the one I pulled out was brand new. I just replaced the gauge with one from eBay. In short, I’ve just been throwing parts at the problem. It also looks like the PO cut the wiring harness in the quarter panel and used scotch lock to reconnect everything. I haven’t been able to do anything about that yet because I’ll likely need to pull the tank and get access to everything to rerun the wires.

With that all being said, I have a spare fuel level sender and a spare gauge cluster laying around now. I’ll hook everything up to my DC bench power supply and try to get some readings and report back when I get a chance.
Click to expand...
I want to know the solution for this because I'm in the same boat. I'll be on E and only fill 13 gallons. Pretty annoying.
 
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