Im about to waffleswaffleswaffleswafflesing lose it, fuel sender issues.

[mcskibadee1]

So heres the deal.

Since I have had the car my gas gauge has always fluctuated, it is never registered full and never registered empty. It never jumped around, it would sort of just sit wherever in no relation to how much fuel I had in my tank. The empty tank light does work so I have always relied on that.

Drivers side sender had ohms jumping all over the place so I replaced that one with another one where the ohms would steadily increase or decrease if I tipped the sender so I assumed this one was good. The passenger side seemed fine but I pulled one from the junk yard anyway along with an early model fuel gauge since I have heard that could be a problem too.

1st try:

I replaced just the drivers side sender and now the gauge sits on empty and SLOWLY (took 3 min) crept up to half way, it should be reading almost full.

2nd Try:

I replaced the passenger side sender and sits at empty, it is just above red.

3rd Try:

So I pulled the gauge and installed the early model and same thing, just sits above empty.

4th Try:

I pull both senders and let them dry. I then plug them in and turn them upside down to mimick a full tank and the gauge sits at 3/4 and as I turn them the gauge seems to respond but as soon as I put them in the tank it is back down to sitting at empty on the gauge.


I have switched out and done every combination and I can never get it to read full when I have them pulled out and they always sit at empty when installed in the tank.

Is there any way to tell if there is a short or to tell if all the correct ohmage (is that even a word?) is getting to the gauge.


I am a total newb when it comes to multimeters but I watched a couple videos so I think I am getting the correct read out. I am measuring the senders when they are unplugged, is there somewhere I should be measuring when they are plugged in? I get like 5ohms on the low end and like 85 on the high end on each sender.

[jlevie]

Each sensor should read 0 ohms when empty of fuel and upside down and 59 ohms right side up. They are connected in series so if you do the same tests with the sensors connected you should zero ohms to ground at pin 4 or connector C2 with the sensors upside down and 158 ohms right side up.

A early gauge for a 55L tank with the single sensor will not read correctly with your car.

[mcskibadee1]

Each sensor should read 0 ohms when empty of fuel and upside down and 59 ohms right side up. They are connected in series so if you do the same tests with the sensors connected you should zero ohms to ground at pin 4 or connector C2 with the sensors upside down and 158 ohms right side up.

A early gauge for a 55L tank with the single sensor will not read correctly with your car.

Wouldn't empty be right side up and full be upside down?

So I checked and here it is

Driver side sender #1 50-80 ohm right side up and 14 ohm upside down (the ohmage jumps around, takes a different number every time I test it)

Drivers side sender #2 67 ohm right side up and 4 ohm upside down

Passenger Side sender #1 59 ohm right side up and 4.3 ohm upside down

Passenger side sender #2 59 ohm right side up and 4.3 ohm upside down

Are all the senders bad? I am testing these out of the car unplugged.

[jlevie]

While not exactly right, Driver side #2 is close enough to work. Both of the Passenger side senders are good.

[mcskibadee1]

Cool, now when I turn them upside down my gauge goes almost to full. If the drivers side one was perfect would it register full? Could it be possible I have a 318is gauge and that is why it is off or is it the ohmage?

[jlevie]

There are two possible fuel gauges. The one for cars with the 55L tank and one level sensor is set up for a resistance range of 59-0 ohms. The one for cars with a 63L tank and two sensors is set up for a resistance range of 118-0 ohms. If you use the gauge for a dual sensor with a single sensor system the gauge will read about half when the tank is empty. Conversely using a single sensor gauge with a dual sensor system the gauge will read empty when the tank is half full. Either gauge will read correctly when the tank is full as that is a sensor(s) resistance of 0.

You gauge not quite reading full is a sign of resistance in the circuit that should not be there.

[mcskibadee1]

Cool, thanks! I will be checking it to see how it goes. I will see how the tank responds.

[dannyyisntt]

Good info in this thread. Reminds me that i've gotta look into my e30s fuel gauge issue..