pauls911

2006 Carrera 997.1 Tiptronic

I've recently noticed that my fuel gauge has been giving false readings. Some times high some times low. My first reaction was a sticking fuel sender. However coincidently my oil pressure gauge appears to be acting up also; I live in Florida so the oil never gets too cold. When I start the engine in the morning the pressure gauge is pegged above "5" (whatever 5 represents) at idle. When the oil heats the pressure is about 2.5.at idle. When running at 3000 RPM the gauge is again pegged above 5. I've had the car 2 years and have never noticed the pressure above 5. Any thoughts on this would be greatly appreciated. Thanks

Since both the fuel gauge and oil gauge problems occurred at approx. the same time could it possibly be the instrument cluster???

jchapura

Regarding the oil pressure, does your dash gage stay above 0 with the engine not running (Key On)?

If it does, it's probably a defective oil pressure sending unit on the right side of the engine up near the intake runners. Pretty easy to change with a crows foot wrench.

SpectreH

Units on the oil pressure gauge are in bar, where 1 bar = 14.5 psi.

Hella-Buggin'

Oil pressure sounds normal to me. It hits 5 on cold start because the oil and engine are cold and the oil is thick. As it warms up is gets thinner and hence the 2 reading. It increases with rpm because the oil pump pushes more oil to match rps. 5 bar is the max because after that a bypass kicks in to protect the engine from blowing a seal from excessive pressure. Rule if thumb is 10 psi per 1k rpm. Anything above that is good.

pauls911

Thanks....one mystery solved

Petza914

Pressure sevder has likely failed. When they fail they read high. Unless you're running a 5w50 weight oil like Driven FR50 your readings are higher than normal, but just by a little bit. As mentioned earlier, without starting the car, turn the key to the full accessory position....if the gauge shows anything other than zero the sender is bad. I had to replace it in both my 997s for this reason.

Astur

Don't know about the oil pressure issue but I had a similar situation with the fuel level gauge on my 2009 C2.

The problem with the fuel level started much as yours with erratic readings and specially even when filling up when it would always be a couple of tick marks below Full. That went on for about 5-6 months but I was not worrisome since I always reset my odometer at fill-up and would replenish at 125 miles. Then about 3 weeks ago the fuel gauge went to Zero and I got a RED WARNING that the Fuel Level Sender was defective and needed immediate attention at the workshop.

Long story short, I ordered a new fuel level sensor/unit from Sunset Porsche and followed the instructions in this video which were pretty straightforward:




Just two things to keep in mind when ordering and installing:

1. When ordering make sure you specify whether the car is a C2-C2S or a C4. The C4 unit is totally different since it has to straddle the "hump" fuel tank C4's have.
   
2. Once the level sensor is installed, the actual fuel level must be calibrated. This involves totally emptying the tank, adding 27(??) liters of fuel and the calibration with a PIWIS. I haven't done this yet but at least the catastrophic warning is gone although the fuel level shows empty with the yellow "reserve" light on even though the tank is full.