runnermedic

today i did the fuel sending unit in my 98 4runner and found that the contacts were really dirty ,so cleaned up and it seems to work now before it was stuck in 1/4 to empty now is marking near 1/2 tank , but my doubt is if the gas level stays marking even with no key,i also own a 1993 4runner sr5 and it shows the fuel level even with the key out.

runnermedic

well did a short trip today and the gas level stills the same so im thinking the fuel sending unit is bad or the po replaced with the wrong one before,i was talking to a friend who works at a toyota parts store and he gave me the correct part number for my 4runner fuel sender
83320-80331,so if anyone is selling one please let me know.

dgoll75

I had a FSU go bad and mine would either show "FULL" or "EMPTY." The fluctuations in yours almost sounds to me like a sticking float or dirty fuel sender. Maybe some Seafoam in the tank? Or some other fuel system cleaner. Just my $.02.

runnermedic

well i did notice that the bracket that holds the sender is not straight it has a bend pointing to the outer tank wall and maybe that is causing the float to hit the wall and getting stuck,the issue is if the bracket indeed needs the bend or not,anyway im going to drop the tank again and test the fsu outside again and try to bend inward the bracket and see if it helps.

runnermedic

update here
dropped the tank today AGAIN!!!!!
fsu tested outside ,low fuel level works,and the fsu was marking right in full,half and empty connected outside the tank,i bend a little the fsu bracket and with a light checked the tank,found some marks inside the tank and the float shows some wear marks in one side the one that i suspect is touching the tank wall.

put everything back together and is marking nearly half tank ,so im going to fill the tank,test by trip meter and see if the fsu works correctly.

runnermedic

NO WAY !!!!!!!!!!!!! full tank and still marking 1/2 tank.
as i said i tested the fsu outside the tank and it works ok(while not using the bracket ground bolt),bolted up the bracket,put the whole assy in the tank and wham!!! 1/2 tank,
maybe maybe maybe who knows the problem is in the damn ground cable,but other day now the tank is full,ill wait with my shotgun in hand, you'll see damn ground you'll see.
i have another story about my new 3rd gen is about brakes and it happens today check my posts!!!!

im really starting to hate it!!!!!!!!!!!!!!!

runnermedic

i feel im talking with my self!!!!!

Greg_Canada

LOL oh dear.

j-man

1999 and 2000 years had a TSB for bad fuel sender units and a revised motherboard for the back of the gauge cluster. Follow this guys info for what he did....should fix ur problem. i need to do it to my 2000.....drives me nuts cause it shows empty when i actually have a 1/2 tank left....

http://www.toyota-4runner.org/3rd-ge...tml#post902919

also...

https://www.yotatech.com/forums/f2/3...60/index2.html

runnermedic

Mine is a 98

runnermedic

found this marine fsu that maybe can work,the only problem is the ohms readings 0-90 ohm where o means empty (toyota is .3-4.6 ohm),maybe with a resistor or something like that it can be limited to the 4.6 needed.

runnermedic

final update here
today i wakeup decided to settle down the fuel sending unit issue in my 98 4runner,well yesterday i was looking some pictures of different fsu and i noticed that the fsu n my 4runner didnt match the one that is intended for the 4runner models.
in my 4runner the low fuel light post goes straight from fsu to the bottom of the tank baffle,in the picture i found it has an horizontal bend in the top then goes straight to the tank baffle another mismatch is the float in my 4runner is rectangular and pointing to the back of the tank in the picture i found is has a square float and the float hanger wire is shorter.
so that means that the PO certainly mess up with the tank and who knows told him that a tacoma fuel pump bracket and related parts were the same.well the fuel pump is ok the fsu meter is ok but the floater ,hanger wire and low fuel light sensor are located different also the fuel pump bracket is longer.
i had to test several times the fitment of the float but i managed to set it up right,bottom part of the float flush whit the top part of the pump filter ,now it moves freely and works right,here are the pictures of the sending units.