Mechanics

WHERE WOULD I FIND THE GROUND ON THE GAS TANK?

1998 Subaru Forester • 152,000 miles

1998 Subaru Forester S 2.5 motor.
I have a code p0463 and the gas gauge is not working. I checked the connection and had the gas gauge working for a little bit, but it died within 2 miles. I think it is a bad ground on the tank. Where would I find the ground on the gas tank?
Thanks
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1maddog
July 15, 2012.




Do you hear the fuel pump come on?

Tiny
Rasmataz
Jul 15, 2012.
Yeah I don't have any problemexcept the gas guage is dead.
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Tiny
1maddog
Jul 15, 2012.
The fuel ank iteslf is the ground for the sending unit which I believe could be faulty.

What did you do to have it working?

KHLow2008
Jul 15, 2012.
In the beginning the fuel gauge would jump from a 3/4 full tank down to 1/4 tank back to 1/2 tank and so forth.

All I did was take the molex connector apart and clean it. I checked the connection to make sure it was solid and not loose. I also held it to ground and watched the fuel gage respond. After I re-connected it and gauge worked ok. I drove about 2 miles and it died again.

Potential causes of a P0463 code include: -The signal circuit to the fuel sender is open or shorted to B+ (Battery voltage)
-The ground circuit is open, or ground path may have high resistance due to rust or missing ground strap on fuel tank
-There's an open in the fuel lever sensor's resistor to ground

I haven't had a chance to look at it yet, but probably will this week and wanted to know where to look for the tank ground as it seems the easiest thing to check first.

Thanks

Tiny
1maddog
Jul 15, 2012.
You would need to test the sending unit. It could have intermittent contact causing the problem.

KHLow2008
Jul 16, 2012.
OK, a little more info for this one. My wife says it only does it (fluctuates) when the tank is under 3/4 full. I took some readings on the connector today. It you are looking at the connector coming from the ECM and going to the fuel tank/sending unit, with the clip on top, I numbered the pins from left to right.

Top 3 are: 1) Blk/Red 0 VDC 2) Red 12VDC 3) Blue 3.9VDC
Bottom 3: 4) bvlk -.5 VDC 5) Blk/Yell -.5VDC 6) Blue 4.2VDC

I could not get a ground reading from any pin to the tank.

Ity looks like I also have a fuel temp sensor in there.

Thanks

Tiny
1maddog
Jul 21, 2012.
If the fluctuation only occurs within a certain range, the sending unit is bad.

KHLow2008
Jul 21, 2012.

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