Porsche Enthusiasts Club Forum

My oil pressure gauge goes to max as soon as ignition is on (engine not running) and doesn't move after starting the engine. It was behaving normally a few weeks ago.

I recall reading this is an electrical issue - loose connection maybe but I cant recall/find the specifics.

Can anyone give me a pointer before I start crawling underneath looking at the connector wires?

Many thanks.

Either broken connection or knackered sensor.

+1 to that...not that hard to get at either with ramps or jack up drivers side and use axle stand its at the lower front drivers side of the engine.

I've had this problem ever since I've had the car. Once it's warmed up there's a 50/50 chance of it working but I've spent ages looking for the issue and never found it.

I fitted a new sender unit earlier this year so I hope thats not gone bad already!

Back on the ramps for a look at the weekend then.

From memory, your oil pressure sender unit will have two wires connected to it. The blue wire operates the oil warning light and the blue and white wire is the signal wire to the pressure gauge. These type of gauges will read full scale if the wire becomes disconnected (open circuit). It may also be possible to connect the warning light and gauge wires the wrong way around on the sender. I can't remember exactly, they may well be different size connectors, in which case ignore that last comment. If they are connected incorrectly though, the oil pressure gauge would sit at 0 and then go full scale when the engine is started. If you earth the blue and white wire out at the connector, ie, touch it into the block of the engine, the gauge should read zero. If it still reads full scale, you either have a faulty gauge or a broken connection between the sender and the gauge. If these tests prove that the gauge is working correctly, then you definitely have a faulty sender unit.

Thanks Pete.

You are right about the different connectors though - when I replaced the sender a while back I noticed the replacement had identical spade connectors so i had to remove the spades from the old sender and fit them to the new one in order to connect the wires. Of course during this process I attached them the wrong way round and had to reverse them after installing.

I'm hoping its just a wire has come loose this time - its just a faff getting the car on ramps and removing the under tray to check!

Well that was a mystery.

Got the ramps out, started up to drive on and noticed oil pressure gauge working normally. Stopped and started a few times - all OK. Still took the tray off and had a look at the connections and everything was solid.

Can only think it was sulking due to lack of attention for the last month