Fuel gauge/sensor trouble shooting issue (1 Viewer)

[mechanixhorseman]

I managed to find another thread related to a faulty fuel gauge, however, it didn't describe the same problem I'm having. I have a feeling I'm not an isolated case, but I haven't seen a whole lot of talk about it.

Here we go. Since I bought my cruiser over a year ago every once in a while when I start her up, my fuel gauge shows the level is either empty or very near empty. Sometimes shutting the engine off and restarting it will resolve the issue, but most of the time it won't. The strangest part is that after driving with the issue for a little bit the level will very VERY slowly start to rise back to it's actual level.

I've noticed it happens much more frequently in cold weather, but lately it is happening more and more frequently in warm weather. It also seems to happen more often when the tank is on the full side. Maybe I just notice it less when the tank is closer to empty. I haven't paid it too much attention, but now that I'm planning some more trips out to BFE, a reliable fuel gauge/sensor is a must.

The other thread I found revealed the buoyant part of the sensor to be the culprit, but the issue in my case is very sporadic, so I'm thinking there may be a different cause.

 

[100 TD]

Update your signiature line with year model.
You can download a 2004 FSM with wiring diagrams here
Toyota Workshop & Repair Manuals - Page: 3




6. INSPECT FUEL SENDER GAUGE VOLTAGE
(a) Apply voltage (4.5 V - 5.0 V) between terminals 2 and 3.
(b) Measure voltage between terminals 1 and 2 for each float
position.
Float position mm (in.) Voltage (V)
F: Approx. 85.3 (3.36) Approx. 4.60 ± 0.1
1/2: Approx. 1.7 (0.67) Approx. 2.45 ± 0.1
E: Approx. 91.9 (3.62) Approx. 0.30 ± 0.1
If voltage value is not as specified, replace main sender gauge.

 

[mechanixhorseman]

Sorry, forgot to mention it's a 98. I have the fsm, but I more wanted to find out if this is an issue anyone else is having. I don't belies it is a short due to the way the gauge behaves.

 

[Travis351]

I used to have this issue back when I bought mine. I found that tightening the fuel cap as tight as possible fixed it. I would say to spin the cap about 3/4 after it starts clicking.

 

[mechanixhorseman]

Seems like a strange solution, but I'll give it a shot. Why do you think that is?

Yours did the same thing to where the level would slowly rise?

 

[Travis351]

Yep...pretty cheap fix. Just like I like them. I think it has something to do with air pressure in the tank.

 

[North100]

Fuel Gauge

I managed to find another thread related to a faulty fuel gauge, however, it didn't describe the same problem I'm having. I have a feeling I'm not an isolated case, but I haven't seen a whole lot of talk about it.

Here we go. Since I bought my cruiser over a year ago every once in a while when I start her up, my fuel gauge shows the level is either empty or very near empty. Sometimes shutting the engine off and restarting it will resolve the issue, but most of the time it won't. The strangest part is that after driving with the issue for a little bit the level will very VERY slowly start to rise back to it's actual level.

I've noticed it happens much more frequently in cold weather, but lately it is happening more and more frequently in warm weather. It also seems to happen more often when the tank is on the full side. Maybe I just notice it less when the tank is closer to empty. I haven't paid it too much attention, but now that I'm planning some more trips out to BFE, a reliable fuel gauge/sensor is a must.

The other thread I found revealed the buoyant part of the sensor to be the culprit, but the issue in my case is very sporadic, so I'm thinking there may be a different cause.

I have the same issue on a 99 LX with about 190K miles. Put in a new sending unit, and no difference - reads empty all the time. Sometimes starts out at half when full, the slowly creeps down. Pulled the instrument cluster aka combination meter, just on the off chance it was a bad connection. No help. Has anyone found what is the cause?