greetings,

I have been troubleshooting a gas gauge problem on my 1999 4-runner, and in my research I have come across what appears to me to be conflicting information.
Several people have cited this website for troubleshooting the fuel gauge system. One of the links at this site has the following information for a 1999 4runner;


"INSPECT FUEL SENDER GAUGE
Measure the voltage between terminals 2 and 3 for each float position.
If resistance value is not as specified, replace the sender gauge."

Even though it says to measure the voltage, I am sure it means resistance. So, according to this page, the resistance should be between 4.6 ohms and 0.3 ohms depending on the amount in the tank.

NOW, compare that to to what I have found on 1996 to 2002 Toyota 4Runner OEM Repair and Wiring Manuals specifically HERE

The important stuff is on pages BE-51 and BE-52

Note how to test the resistance of the sending unit, and how to check the gauge.

INSPECT FUEL SENDER GAUGE
Measure the resistance between terminals 1 and 3 in each float
position.
Float position: mm (in.) Resistance (Ω)
F: Approx. 39.4 (1.551) Approx. 184Ω
1/2: Approx. 56.0 (2.205) Approx. 97Ω
E: Approx. 148.9 (5.862) Approx. 12Ω

The differences are the pins to measure and the measurements themselves.

Can anyone confirm which way is correct?? When I measure using pins 1 and 3, my resistance measurements are in line with the chart, but when I use pins 2 and 3, they are way off....

I am not sure what to think here. I tend to believe the 2nd one since it appears to be from the FSM, but the first one looks legit as well??

Can anyone with a known working system take the time to take these measurements and confirm which set of instructions are correct?

 

FYI The fuel gauge reading on these trucks are pretty bad. I've owned 3 and none work very well.

 

I second what BajaRunner is saying.
Out of 4 pre 95 yotas I have owned/own none of them were dead on. Mostly they were pretty far off.

 

I understand and agree that the gauge has issues. What I cannot seem to find out is which of these two methods for testing a sending unit is correct?

 

Go to your local Toyota dealer and ask them which is correct, most Toyota dealer service managers are always willing to help. I use a factory service manual for servicing my truck (1983) and the information in them has always been correct.

 

I'd be willing to bet the FSM is correct and not the other website.

 

I just recently had a fuel gauge problem and managed to fix it (It was a melted terminal on the back of cluster board) link here: https://www.yotatech.com/forums/f2/3...l#post52504493

During the course of troubleshooting, I did the test both ways (Haynes manual says terminal 2 and 3, FSM says 1 and 3..FSM is right apparently)
2 & 3 got me a reading of 203-205 constantly regardless of float arm position
1 & 3 got me reading of approx 180 in top, 100 in half, 12 in bottom (its the exact opposite of what it says it should be but it measured very accurately)

Try cleaning all the metal on the fuel sending unit and resolder, it might help (Idk if it helped me but I did)