I don't have the resistance values for the sensor, but, they are likely in the service manual, I would think. Do the math, and see if the voltage reflects anything near how much gas you think it in the tank.....

 

Thank you for all the help thus far….

I remembered yesterday while I was checking the voltage on the blue/white trace wire at the fuel pump connector that I was getting over 10 volts to that wire with it unplugged from the unit. Does that seem high? I remember reading that it should be around 5 volts?

 

Yeah, the gauge sensor gets its feed from the PCM, which is typically 5 volts.....

 

Here is a trip.

I have noticed that when I get under 10 gallons of gas or less my gauge pins to full and does not move.

I just filled up my 35 gallon tank tonight with 26 gallons of gas and immediately my gauge dropped down to below E.

It will stay on E now until I get low enough on gas again lol.

Gauge is backwards for sure.

 

I ordered a used instrument cluster off of eBay and installed it yesterday. Everything works perfect but the fuel gauge. I back probed the black/blue tracer sensor return wire at the fuel pump and it is reading 50ohms which is accurate with the amount of fuel I have on the tank. Not sure what else to do besides swapping out the PCM.

 

Plug in with a scanner, and see if you can find what the PCM thinks the gauge state is. Probably need a pretty high zoot scanner to find that little bit of data....

 

So I think I am getting closer to narrowing down the core issue. Tonight I back probed the blue with white tracer wire while it was plugged in to PCM connector 3 and I am only getting .345 volts. I then ran a power wire from the battery and jumped it into that blue/white wire at the PCM connector and the fuel gauge jumped to full.

 

That should be a 5 volt circuit.... feeding it 12 might cause some issues with other sensors on the same feed.

 

I snipped the black with blue tracer wire (sensor return/PCM 1) as it seemed to have an effect on my low voltage coming from the fuel sensor wire (PCM3). Well, I now have 5 volts coming from the PCM but now the trans temp and od off light came on. Gauge went to 1/8 tank with the fuel light on. I was hoping that sensor return wire to the PCM was only for the fuel gauge but it seems to be running other sensors.

 

The sensor return wire (PCM connector 1 pin 4) for the fuel gauge looks like it splices with multiple sensors. This might explain why my fuel gauge moves to full from dead empty every time I step on the throttle and floor it. There might be a sensor that is grounding out my fuel sensor wire. Any input?