Gas Guage 1/4 incorrect

So my taco has had for a long while now incorrect gas level by 1/4. I have changed the fuil sending unit and have had the cluster re set and new fuel Guage motor was also replace. Still no fix. Anyone have any idea what it may be?

 

When you say off by 1/4 your saying when the tank is full the gauge shows only 3/4 or when the tank is empty it still shows 1/4?

 

You've already done more than I'd have done. I'd fill-up, set the trip meter and fill up again at around 250-275 miles for everyday driving and 275-300 on road trips. I almost never pay any attention to the fuel gauge.

 

I do the same. My gauge only goes gown to 1/4 tank then you are walking. My 2nd gen is not a daily driver so it is no big deal to me.

I was thinking of replacing my pump/sending unit, but hearing your experience has changed my mind. I will just keep resetting my trip meter.

 

Looks like you replaced a lot of parts.
I'd be checking resistance at the gauge cluster (pins 8 and 4) or ID2 connector. (pins 2 and 5)

Fill the truck up with fuel, check the resistances.





ID2 Connector



Gauge Cluster Connector

 

Exact same thing on my 06, as mentioned i just get gas every 250 miles.

 

If I fill up. It's all the way. When it's on E it's at about 1/4 on the Guage

 

In that case, run it until it on 1/2 an do the resistance checks above.

 

Thanks I'll do that

 

Is it actually empty or is that just when the fuel light comes on? If it's the fuel light that perfectly normal. If it's actually empty then the only thing you haven't tried that I could suggest would be to take the cluster out, open it up and pull the needle for the gas gauge and reposition it back a couple degrees. I've done it on another car because I hated that the fuel warning light came on so early. Still showsa full when I fill the tank, but now the warning light comes on when I'm below 1/8 tank.

 

In 50 years, I've never owned or driven any vehicle where the needle gauge is really precise. Just an estimate. From experience I always know for 90% certainty, when the needle is at the half level, I really don't have a half tank of gas left. Needles always seem drop at a faster rate around the half tank point. I always try to refill before the light comes on, although I probably still have 50 miles left with the light. Rare case when the light comes on, I stop immediately at the first place I see.

 

My needle seems to be hour glass shaped.
Slow from Full to 3/4.
3/4 to 1/4 drops fast.
Then slow again at 1/4 to E.

 

Take a look at this gas tank and tell me you're surprised that the fuel gauge isn't linear.

 

Exactly my same experience. When I fill it up, I usually pack as much as possible in. Then it seems I can go 100+ miles (on the highway) before the needle moves off full and down to the 3/4 mark. Then it starts dropping faster. I don't like to push it below the 1/4 mark unless I have to. Never really paid exact attention to the needle position vs. how much to fill back up. But I probably would if I noticed a huge discrepancy in the gauge reading vs. the pump reading like the OP might have discovered.

Also another possibility to consider. I think most states have inspectors that visit every gas station periodically to check the pumps for accuracy of the volume. Maybe once a year or maybe less often, I don't know. I know that years ago in GA, I filled up a car that was running on fumes. The total number of gallons surprised me and when I got home I checked the manual and it was 2 or 3 gallons more than the book stated as the tank capacity. Went back later and spoke with the store manager and she told me she would have it looked into. She adamantly stated they would make sure any problems in that area would investigated and fixed immediately. I didn't have any concrete proof to pursue it further, so I didn't.

 

That's what I've experienced in every vehicle I've driven. From what I've heard, it's a combination of two things. Most explanations say that it has to do with the physical constraints of the float. "They say" it's not as responsive at either end of it's travel arc, whether it's encountering full submersion or the resistor isn't as linear at either extreme. Second, it's the shape of the tank itself - most tanks by design are roughly wedge shaped. Therefore depth won't have a linear relationship with volume.

At least that's what I've heard.

 

I use the trip indicator unless using AC and only panic if past 420 miles as there is only about a gallon left

 

The fuel gauge is consistent, +/- 0.5 gallon:

FULL= 21 Gallons in the tank
3/4 Line = 16 (down 5 gallons from full)
1/2 Line = 12 (down 9)
3/4 Line = 8 (down 13)
Low Fuel Light = 5 (down 16)
E Line = 3 (down 18)

From this thread #68:
https://www.tacomaworld.com/threads/how-many-miles-per-quarter-tank.603857/page-4

 

When It shows 1/4 on the guage that's when its time for a fill up but also like someone mentioned my needle starts to drop pretty quick from full after about 80miles

 

Does anyone know the solution to this issue ?

 

Have you verified the resistance of the sending unit is correct as @TnShooter posted above?