Fuel Gauge Nightmare

[infocusf8]

I have a '99 Boxster that has 82K miles and I'm the third owner. When I bought the car, from a dealer, it had a 3/4 tank of gas or so I thought. When I filled up the gas gauge only registered just above the 2/3 mark. The dealer wouldn't do anything about it as it was purchased with no warranty, so I took it to a well known independent Porsche shop near where I live and was told it was the sending unit so I had it replaced and the needle still didn't go to full even after I pumped gas into the tank after the nozzle shut off. The shop told me to bring the car back and they would empty the tank and put back in a required number of gallons with a PS2 hooked up to recalibrate the system. After doing this and $440 later the gauge still doesn't read full after filling. The shop told me it is the gauge and I will need to have my instrument cluster removed and sent off for calibration. I took the car to another independent shop for a second opinion and the mechanic found that the hoses from the sending unit had not been tie wrapped in accordance with the sending unit installation instructions and the alignment marks were not set correctly when the sending unit was installed so I paid to have that done. Upon filling up the gauge now is back to the original 3/4 mark and at one point stuck at that position for almost 200 miles before it finally went down to below the halfway mark where it should be. I have yet to refill the tank to see where it lines up but I'm wondering if anyone else has this problem and what you did to fix it. The problem is not the carbon recovery as that was checked by the second shop and tested ok.

Edited April 27, 2010 by infocusf8

[4agdtym]

I occasionally have trouble with the gauge reading accurately when I fill the tank - but not on the way down. I remember seeing a TSB regarding the tie-wrapping you had done. I'm surprised that the dealer didn't notice that right off the bat. I haven't completed the tie-wrap procedure. I'm not concerned enough since I have no trouble as the tank empties.

[Wayne R. Dempsey]

I went through this with our project Boxster - very frustrating. After installing and removing the fuel sender many times, I finally got some fishing wire, and threaded it down the fuel intake hole and tied it to the sender. Then I had someone pull it up and down while I was watching the gauge. It turned out the sender *was* indeed catching on the hoses, even after I had zipped them out of the way. Tricky little bugger, I wrote an article about this same problem, it's up here: http://www.pelicanparts.com/techarticles/Boxster_Tech/22-FUEL-Fuel_Pump/22-FUEL-Fuel_Pump.htm

Hope this helps,

Wayne

[xavi.ordonez]

what do i need to zip tie to? can you please elavorate. thank you

[Wayne R. Dempsey]

The flexible gas hoses in those pictures need to be zipped away from the long float wand that moves up and down.

-Wayne