1998 Fuel Level Gauge and Light Help

[shamrok]

Kinda at wit's end with this one. I've read every applicable thread on inaccurate fuel levels on the internet I can find about this thing and still can't make sense of it. Normally I'd just live with it, but this is my daughter's first car, and I'm just waiting for her to forget to set the tripmeter one day and run out of gas.

Anyways, it's a MY 98 SR5 4WD (late 1997 build date) with the early gauge cluster, so the TSB for 99-00 models doesn't seem to apply in any way. Things I've done.

• Dropped the tank, replaced the sender with a new one (pn 83320-35530), tested resistance on it (and the old one) and it's good.

• Took out the gauge cluster, cleaned all contacts

• Added ground wire to chassis from the 5-pin connector

• De-pinned and re-pinned 5-pin connector to pump/sender

What else am I missing? There's not much to the system when looking at the EWD, maybe the cluster isn't original and the resistance readings aren't correct for it? Is there a different sender I should have used? There doesn't seem to be a clear part number to use on earlier 3rd gens.

 

[JWaldz]

[MENTION=39832]shamrok[/MENTION]

what's the gauge actually doing? Does it work at all, just inconsistent, or does it show full/empty/same spot all the time?

 

[GhostRing]

I wish I had a instant solution, but I have dealt with a similar situation with my '98 for years and am finally getting a little tired of it.

What exactly is yours doing? Just not being consistent, or is the needle freezing? Mine will show full upon fill-up, then once it gets to
2/3 full, the needle stops and nothing happens until the fuel light goes on (at an atrocious mileage, but that's likely my fault).

I tried the ground wire, but haven't dug any further, since like you said - you learn to adapt, but I'd prefer it to function normally.
Do you think your daughter would tolerate an Ultra or Scan Gauge? Between that and the trip meter, I am comfortable travelling.

 

[shamrok]

Gauge is showing just shy of 2/3 when the tank is full (confirmed the tank as actually filling up completely, 18ish gallons went in), tank shows empty after less than 100 miles, light is always on.

Before I put the tank back in, I tried every possible combination of wiring for the 3 main wires to the sender and could not get the gauge and/or light to behave as expected together.

Thought about getting a ScanGauge, but what is that reading from? If the sender is sending it garbage, well...

 

[phattyduck]

Thought about getting a ScanGauge, but what is that reading from? If the sender is sending it garbage, well...

The ScanGauge reads fuel usage from the ECU - which has no knowledge of the level in the tank. It would be a 'fancy' version of just resetting the trip meter, which requires user input at every fill-up.

The low fuel light on the early ('96-'98) is a separate element (NTC thermistor) from the fuel level (resistance wiper / potentiometer). The low fuel light should be VERY reliable - if it is always on, there is likely something wrong in the wiring or cluster. Getting to the bottom of it might take an FSM wiring diagram, a multimeter and some skill in understanding electronics.

-Charlie

 

[shamrok]

Getting to the bottom of it might take an FSM wiring diagram, a multimeter and some skill in understanding electronics.

-Charlie

I'm pretty smooth brain but have owned a lot of Toyota trucks, so I did exactly that and after testing the resistance on both the new sender (pn 83320-35530) and the old one (which I suspect was replaced at some point with an incorrect newer version), I discovered that they're not only different values, not only reversed values, but possibly different connector pinouts. So neither sender was ever going to work with my 98's gauge and it explains why the PO had the 5-pin connector taken apart trying to fix it themselves.

98 FSM on left, 2000 on right, the senders I tested have the 2000's values.

It looks like 83320-80331 is the correct part number, but it's the entire unit with pump, tubes, connector, etc. Anybody know if there's a fuel sender only that corresponds with this part?

 

[fourfive]

• Dropped the tank, replaced the sender with a new one (pn 83320-35530), tested resistance on it (and the old one) and it's good.

• 
  
  Where did you get your new fuel sender? Toyota dealership/online Toyota dealer, Amayama, Amazon, Ebay?
  
  When my fuel gauge stopped functioning properly the new Toyota fuel sender I replaced it with fixed the issue but I also replaced the fuel suction tube assembly with a new Toyota part at the same time which may have contributed to the fix. Both the new & old sender tested good too, weird.

 

[shamrok]

I got the part from Impex, and it's definitely OEM. It's just the wrong part haha

 

[PolkaSaucy]

I'm pretty smooth brain but have owned a lot of Toyota trucks, so I did exactly that and after testing the resistance on both the new sender (pn 83320-35530) and the old one (which I suspect was replaced at some point with an incorrect newer version), I discovered that they're not only different values, not only reversed values, but possibly different connector pinouts. So neither sender was ever going to work with my 98's gauge and it explains why the PO had the 5-pin connector taken apart trying to fix it themselves.

98 FSM on left, 2000 on right, the senders I tested have the 2000's values.

It looks like 83320-80331 is the correct part number, but it's the entire unit with pump, tubes, connector, etc. Anybody know if there's a fuel sender only that corresponds with this part?

I know this is kind of an old thread, but just wanted to first say thanks for this, it helped a lot. Second, for anyone else looking, I haven't tried it myself so I can't confirm, but here's a link to the sender itself for a decent price:
https://ebay.us/m/yGAfye

Thirdly, I did a work around and ended up just installing an aftermarket gauge that was compatible with the incorrect sender that I'd already dropped in my tank. I made a video of the process, that can be found here:
https://youtu.be/1US2hOy23OU?si=Va9Z7ubpvjNkrrtD

 

[jasonw3]

The low fuel light on the early ('96-'98) is a separate element (NTC thermistor) from the fuel level (resistance wiper / potentiometer). The low fuel light should be VERY reliable - if it is always on, there is likely something wrong in the wiring or cluster. Getting to the bottom of it might take an FSM wiring diagram, a multimeter and some skill in understanding electronics.

So if I've had a low fuel light constantly on for 15+ years but the gauge works normally, the issue is likely in the cluster and not the sending unit? I've inspected the outer portion of the tank but was never frustrated enough to drop the tank or replace the entire sending unit. I'd love to fix it but have lived with it for years.

 

[phattyduck]

So if I've had a low fuel light constantly on for 15+ years but the gauge works normally, the issue is likely in the cluster and not the sending unit? I've inspected the outer portion of the tank but was never frustrated enough to drop the tank or replace the entire sending unit. I'd love to fix it but have lived with it for years.

Try unplugging the wires to the tank first - if the light stays on, it isn't a problem in the tank... If it goes off, it is somewhere in the tank. You can probably just remove one wire from the connection to the tank to get the light to go off if it is an issue in the tank (maybe the wire constantly being grounded, either mechanically or through a failed thermistor).

-Charlie