Fuel Sending Unit? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Brockmeister · 07-25-2011, 05:09 AM

Hi All. It seems that my gas gauge doesn't want to go past half way. I had this problem on my '88 944 and it went away after I replaced the fuel sending unit.
I speculate that the same solution will work for the Boxster. Any thoughts ont this? Is this going to be a royal PITA or what?

Jager · 07-25-2011, 09:24 PM

Float is probably stuck inside the tank... It happens.

jhandy · 07-25-2011, 11:18 PM

from the net:

Gas Gauge Out of Calibration

Diagnostic: The gas gauge on the dashboard reads low even when the tank is filled.

Cause: Miscalibrated gas gauge.

Details: The gas gauge can be calibrated using the PST2 (Porsche System Tool 2). The gas tank must be completely drained. Then a precise amount of gasoline is introduced into the tank. Then the PST2 is used to calibrate the gauge needle.

Time in Shop: One hour.

Repair Instructions: Requires dealer repair.

ppbon · 07-26-2011, 06:54 AM

... both things.
A stuck float and the need to calibrate.
To get to the float you'll have to remove the battery, the battery tray and then you'll get into the tank. If you go this route you'll need a new gasket because the OEM will be swollen and won't fit after it's removed.
Finally it may be necessary to calibrate and you'll need either a PST-II or a PIWIS computer to do so.
Happy Boxstering,
Pedro

Brockmeister · 07-26-2011, 06:56 AM

I suspect it's the fuel sending unit. Sometimes it works, sometimes it doesn't. I would think that if it was the gauge it wouldn't go back to normal w/o the calibration. Anyway, I bought one on eBay. I'll see how it goes.

kotto · 04-09-2012, 07:21 PM

hi guys, My fuel gauge is not working. It most often reads above the full level, but also fluctuates anywhere between there and about 1/4 tank. I think it's the fuel level sending unit. Is it possible to pull the fuel pump up through the opening in the trunk and just replace the sending unit? Or do I have to replace the entire pump?

Brockmeister · 04-11-2012, 05:49 AM

I haven't gotten this fixed yet. The indy I took it to said it would cost a lot more than an hour of tech time to fix. I'll be taking it to someone else tht has the PWIS tool.

milliemax · 04-11-2012, 04:21 PM

Could be that a hose from the fuel pump has shifted and is troubling the float. On "fuel pump replacement" it states exactly where to place the pump hose lines to avoid interference. Just a thought ? Alot going on down there in the tank. Might find traces of "Danger"?