Fuel Sending Units

[chealy]

I have a 1995 4 door Sidekick 1.6l 16 valve engine, 4wd, manual transmission. 

I’m having some issues with getting fuel level to read correctly. The needle works, but when I fill up it doesn’t go all the way to full. It will go to around 3/4 or 7/8’s. Now if I stand there and very slowly pump about 2 more gallons of gas into the tank (like a third of a gallon at a time) I can get it closer, but its dang annoying and something I don’t love doing. 

A little backstory on the vehicle. It originally had the bigger tank, but several years ago got some rust in there and had to be replaced. The shop that replaced it said they couldn’t find the bigger tank so we put the smaller one in there. I do not know if they replaced the sending unit at this time or not. Then more recently while I’ve been restoring it, I found the bigger tank from Japan, so I ordered it and thats what’s on the car now. The sending unit was replaced at the same time, but it’s reading like I described above.

I’m wondering a few things:

1) I’ve seen different part numbers for the sending units. Does that affect how they read, or is that more just about fitment in the tank? Like, if you put the sending unit for the smaller tank in the big one would it read correctly? And vice versa, if you put the sending unit for the bigger tank in the smaller tank would it read correctly? 

2) What else could cause this, and what could I do to get my needle to go all the way to full upon fill up?

I have searched up, down, and all around for info about this and can’t find exactly what I’m looking for. So any information about this is more than welcome. 

Thank you!!

[fixkick]

I have a 1995 4 door Sidekick 1.6l 16 valve engine, 4wd, manual transmission. 

I’m having some issues with getting fuel level to read correctly. The needle works, but when I fill up it doesn’t go all the way to full. It will go to around 3/4 or 7/8’s. Now if I stand there and very slowly pump about 2 more gallons of gas into the tank (like a third of a gallon at a time) I can get it closer, but its dang annoying and something I don’t love doing. 

A little backstory on the vehicle. It originally had the bigger tank, but several years ago got some rust in there and had to be replaced. The shop that replaced it said they couldn’t find the bigger tank so we put the smaller one in there. I do not know if they replaced the sending unit at this time or not. Then more recently while I’ve been restoring it, I found the bigger tank from Japan, so I ordered it and thats what’s on the car now. The sending unit was replaced at the same time, but it’s reading like I described above.

I’m wondering a few things:

1) I’ve seen different part numbers for the sending units. Does that affect how they read, or is that more just about fitment in the tank? Like, if you put the sending unit for the smaller tank in the big one would it read correctly? And vice versa, if you put the sending unit for the bigger tank in the smaller tank would it read correctly? 

2) What else could cause this, and what could I do to get my needle to go all the way to full upon fill up?

I have searched up, down, and all around for info about this and can’t find exactly what I’m looking for. So any information about this is more than welcome. 

Thank you!!

not sure on the details there,?

• the needle never goes full (max)?
  
• the tank not full, ?
  
• or both.?
  

I will guess #1
if the gas station nozzle clicks off too soon, is this it?  that means 1 of 4 things
first off no tank on any car fills 100% ever, (or on a hot day the fuel expands and the gas leaks out vents)
1: the pump nozzle at the station is bad, use  a different gas station to prove that.
2: the cars filler nozzle  has bad vents at this point or is missing parts. so air can not reach that point .
3: any or all EVAP tank vents blocked, hoses pinched, etc.
4: or is normal (calif nozzles are  a PITA)

is this  a STATION fillup California style nozzle, with huge bellows and spring,  if yes that is even more tricky to get to work on old cars.
a non calif. nozzle is just a pipe. just metal. and lets air sneak around the pipe making easy fills on the tank.<< never fails  to work mostly.

I drove motor cycles for years and calif nozzle all fail hard as my MC have no vents to all allow calif nozzles to work unless I hand forced the bellows back so air can flow and not trip the filler valve off line.closed. I;d go out of my way to find stations with normal filler nozzles on all my bikes, (had 6 then)

the FSM covers the gauge test, we simply short out the wire to the thank fill pot , the tank filler pot is  huge variable resistor (wire wound) and goes super low resistance
full. (at filled fully up)  shorting it to ground is the FSM steps on testing the GAUGE, easy as pie.

here is the spec on 96 tank.

[fixkick]

now the data, from the 96 book off the #1 sticky called documents.
fuel page chapter 6C (not much there but R&R)
sender in take, and gauge both have 2 simple tests.
the gauge wire or wire from it to tank is shorted. to see F on scale of gauge.

chapter 8C
I have no idea at all if senders very by tank sizes. (vertical depth is the issue here, if tank is wider , it is not a problem)
the book is huge not sure which pages cover this (forgot after 10 years, lol)
bingo found the old TSB covering all this.
I will post it now using free PDF site
sender, is
3 ohms full
32 ohms 1/2 full
100 ohms empty.
they did this to make all clusters the same P/N when many tank sizes used world wide (Vitara, too)


here it is

https://drive.proton.me/urls/4SHV4HF5D0#473jqzIdZSlJ


free, TSB from suzuki back when.
34810-70E10

i get hits like this.

https://duckduckgo.com/?hps=1&q=suzuki+3...3-1&ia=web

[fixkick]

full is
3ohms +- 3 ohms so 3-3 = 0 ohms full. and is same value as shorting the wire to it and seeing the gauge go to Full.
this is spec for full.
a very crude and simple device it is.


long ago my answers were better (grin, im older than dirt)

https://fixkick.com/forum/thread-fuel-gage-sending-unit



or better yet my tank pages

https://www.fixkick.com/sensors/fuel-gauge-tests.html

in 1996 (EPA.gov new EVAP laws and new tests for same)
the gauge sender was upgraded. to 1% accuracy !
EVAP EPA monitor test must not be run if tank if full. so the sender was upgraded so false evap tests, are not tripped. DTC errors false ! (yours has no EVAP test 95)

this is not important to you but gee, what if old senders are not sold now. 29 years later, (happens)
then we use 96 parts here.
this is my comment on parts. harder to find.
and tank size matters, for 2 to 4doors laster is bigger.
I no longer have the real SUZ part list for 95, sadly.


the dealer still lists it here


https://www.suzukicarparts.com/oem-parts...wtbDQtZ2Fz


Sending Unit - Suzuki (34810-60A11) ID #9

60a code means first G16 engines SV416 bodies.

[fixkick]

the gauge is really a thermal device.
key off the gauge guts cools and needle goes to 0, does yours?
if yes
then key ON.
we short its gauge input wire (from sender) to ground and the meter heats up and goes to FULL
that is all there is to the easy test. no bath in fuel ever. we test the gauge first.
at the sender wire. anywhere along its length.
if this passes
we look for wire rusted pins on that wire to the tank. no rust allowed. on the wire or the tanks ground.
then wrong sender or bad.