Got an 87 4runner.

My fuel gauge reads great when the tank is full. When I get down to about half full, the needle bottoms out.

After I fill up it jumps right up to full again and is pretty accurate until half a tank.

The fuel light works fine and I keep an eye on my mileage so it's mostly an inconvenience for those who aren't don't understand the truck intimately.
Like, my wife who worries about it. But on the up side, she fills it up every time she uses it.

It would be nice to have it working.

 

bump mine does the same thing. its obviously either the bober in the tank or the gauge. but a way to test it out would be nice.

 

my guess is that its the float in the tank. ive never seen one for a toyota but it seems that it would be fairly easy to fix/replace

 

mine does the same what you can do is drop the tank and clean out the wire conectors and get them clean see if it works then or replace the sender but you have to drop the take to do it not the same as the fuel pump it self its at the back of the tank just so you know

 

Seen and fixed 100x @ the dealer. The sweep area on the sending unit, it's a variable resistor, get's worn down. As the float drops through the rough area, the gauge on the dash behaves erraticly. My personal truck has started doing this recently.

Unfortunately, the only 100% fix is to replace the sending unit. For new owners, there's an access panel under the rear seat - so no need to drop the tank.

 

the under seat thing is for the fuel pump though the sender is at the rear of the tank right?

 

Not as I recall. All the electrical components (fuel gauge, pump) are in one assembly which is under the seat access panel. You may be thinking of the vent on the other side of the tank. It's there to allow high speed filling, and it's part of the evap system.

 

My '84 does something similar, but check this out. Above half a tank it reads fine and then bottoms out below half a tank like yours, until I get on the freeway and then it reads accurate until I slow down or get back on the street. LOL, whats that all about?

 

Your sending unit is bad, and there is no way to fix it other than replacing it, and its not a cheap part.

 

where can i get a new sending unit for a 1987 4runner?

 

So has anyone replaced the sending unit.My vrod (Harley) did the same thing .I was able to clean the variable resistor with emory cloth.

 

My '85 did that (probably as a result of the PO installing the battery backwards), would drop to empty after about 3/4 full. Had the dealer install a new sender and all is fine now.

 

joining the frustration, where can i get my hands on a new sending unit?

 

Exactly the problem I have.
My fix is to put gas in every 400km, or when my Low fuel light comes on.

Glad to hear its the sending unit, and that it is a replacement part..

 

i have a question to add...is there a way to test it?? mine doesent work at all?

lmao i asked this question not to long ago, and i got like 1 reply...this thread is brought back from the dead, and theres like 15 people that have the same prob, go figure...you can get a sending unit from autozone. (special order) it think for like 75-100 bucks. orr you can get a used one from a junkyard and see if it works? but then your taking the chance of it not working...but for me (ive got a 3" BL) its very easy to get to ....

 

Cheap solution, you fill at say x miles, post a note on dash for 300 miles or so beyond that, depending on milage and tank volume. Works for me, axcept when i forget to look at the note.

 

I keep a log book in the glovebox.. helps me to track my mileage also..

 

I would try looking in the FSM to see if there is a way to test the sending unit, otherwise the only place to get a new sending unit is from the dealer, and the last i heard there about 250 dollars.

 

Log book, Ayup know m well, mine goes back to 1989, lost the start up log from Oct 1987.

 

I use a log also kept in visor,I brought the thread back today .I was gonna post but used the search engine first.I'm gonna pull mine soon and look at it to see if I can repair it