Fuel gauge not displaying correctly after Fuel Sender Unit replacement
 

I had to replace the fuel sender unit on my 2000 Boxster base because of a leak, fuel gauge has always indicated correctly. Before doing the job tank was almost empty, low fuel light on, gauge sitting on top of the lowest line.

Replacement was smooth, i did my best to ensure the float is not obstructed by any fuel lines inside the tank and also that the top of the unit is lined up correctly (arrow on top aligned with the 3 lines on the fuel tank). Once buttoned back up, all worked well, gauge was exactly in the same position as it was with the old sender unit (bottom line on the gauge, low fuel light on).

I filled the tank up completely (took 14 gallons) but now the gauge indicates exactly half tank.

Could this be a faulty fuel sender unit or the float is stuck on something?
From the research i did there is nothing to reset, nothing to adjust on the unit prior to installation.

Any thoughts would be appreciated. I was going to drive it and refill again and see if that helps, otherwise i might need to get in there again.

Thanks,

Cristian

Sounds like something is interfering with the float. That was my biggest worry when I did mine.

I second what Beelzy said. Can you access the sender with the tank full without gas spilling everywhere?

You may need to calibrate the sender using the factory procedure and at least a PST-2.

Thanks for the answers gents! I can certainly get in there again but it's a bit of a pain and I rather not redo the job if it needs a calibration instead. A Porsche mechanic friend is looking into it to confirm if there is a process for it. Paul might be right but if I hope I can do it with the durametric I have.

Ay caramba! That sounds like a PITA. Thanks Paul, I'll look into it.

The boxster don’t need calibration only the 996 as the tank is a different shape.
Chances are when you put the sender back in you put the wire the wrong side of the float. If it goes across the front of the float it catches.

Sorry, but that is not correct. The Boxster definitely should be recalibrated, "Calibration is required after replacement of the fuel tank, fuel level sensor, or instrument cluster", and the procedure is covered starting on Group 2, page 20-9 in the factory service manual.

After further research it seems i must indeed recalibrate the fuel gauge. I'm trying my best to avoid going to the dealership and the only independents around here are pretty pricey as well.. I've seen some info saying you can phisically move the fuel gauge needle and that would do it.

I'm thinking filling it up to the brim, taking the gauge off and setting the needle to the top position. I only have a Durametric and that's not enough to do the proper fuel gauge calibration procedure. Any thoughts on that?

Thanks,

Cristian

That will only damage the gauge. It needs to be recalibrated properly.

yeap! i'll bite the bullet and go to a shop. thanks JFP! I'll report back.