Fuel Gauge and tank size - Toyota 4Runner Forum

Paradise87 · 04-19-2012, 12:50 PM

I have an 87 4Runner and the fuel gauge only works for about 60 miles then it hits the bottom quickly. Any ideas of a problem? I would think that the sending unit either works or it doesnt but could be wrong.
I have been told the fuel tank can either be 14 or 17 gallons. Is there anyway to tell with out draining all the fuel?

Thanks for you help.

Thurlo76 · 04-19-2012, 12:59 PM

maybe you just get really ****ty gas mileage? ive read that the 1st gen 4runners all came with the 14 gallon tank, i know that the tank was even dropped about 2 inches because the buckets for the rear seats so there would be even less room under there for a 17 gallon tank.

KidVermicious · 04-19-2012, 01:17 PM

Quote:

Originally Posted by Paradise87

I have an 87 4Runner and the fuel gauge only works for about 60 miles then it hits the bottom quickly. Any ideas of a problem? I would think that the sending unit either works or it doesnt but could be wrong.
I have been told the fuel tank can either be 14 or 17 gallons. Is there anyway to tell with out draining all the fuel?

Thanks for you help.

Run until it's empty then fill it back up.

The sender gets dead spots, that's likely what you're running into with the gauge.

GonOvr · 04-19-2012, 01:20 PM

Your sender works off resistance. More than likely there is a crack in the contact board of the sender making it read just below full. Once the float causes the sensor to go past this point, it doesn't make a reading anymore and the gauge defaults.

GD ninja's

Paradise87 · 04-19-2012, 02:46 PM

Im actually getting 20+ mpg. I siphoned the tank and then filled it back up and it took 14 gal. Then a dealer told me it is a 17 gal tank so makes me wonder and without the fuel gauge working.......makes me wonder if I got all the gas out or not.
Guess I'm gonna have to run it dry.

SV_Dude · 04-19-2012, 04:20 PM

Quote:

Originally Posted by Paradise87

.makes me wonder if I got all the gas out or not.
Guess I'm gonna have to run it dry.

If you pull the skid plate off you'll see a drain plug in the tank if I remember correctly.

I have never seen a 14gal tank in a 4runner. I have heard that some of them did but I have only seen the 17 gallon tanks.

fourwd1 · 04-19-2012, 09:28 PM

Quote:

Originally Posted by Paradise87

I have an 87 4Runner and the fuel gauge only works for about 60 miles then it hits the bottom quickly. Any ideas of a problem? I would think that the sending unit either works or it doesnt but could be wrong.
I have been told the fuel tank can either be 14 or 17 gallons. Is there anyway to tell with out draining all the fuel?

Thanks for you help.

The gauge sending unit is a wire wound potentiometer (variable resistor).
The windings get corroded over time, creating dead spots. That's why it works a little then stops. Sometimes it will work/not work at various spots throughout the range.

If you pull the sending unit out and clean the windings with electrical contact cleaner, you may be able to get it working again.

As for tank size, run it down past E and fill it. If it takes 12-13 gallons to fill it, you have a 14 gallon tank. If it takes 15-16 you have a 17 gal tank.

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