Just picked up a 2002 C4 today. On medium hard accel in 1st or 2nd gears, I got a warning chime a couple of times. I watched the oil pressure gauge on a 1st gear accel and it dropped to zero for a second. The dipstick showed oil up to the upper dot which to me seems normal (no owner's manual yet). I checked the level with the engine shut, warm oil, car on level surface. Does this car have a dry sump or some other system that would necessitate checking the oil with the engine running (or any other unorthodoxed procedure)? I can't believe one could empty a 911 sump under these normal driving conditions. I suspected a faulty gauge or wiring but the condition only seems to come under accel which makes me think the pressure sender and gauge are behaving correctly. Also, what weight oil please?

 

0-40 mobil 1. Checked with the engine off. I would double check your wiring to the sender. If that isn't it, then you probably need to get it into a shop and get it looked at.

 

Thanks, Doc. I think you're on to something. We took the car to dinner last night and the drop in the needle was more prevalent, but now on accel, decel, sometimes cornering, occassionally during straight line cruising. When the needle dropped, it dropped like a stone. It's return was also instantaneous. Not like pres. variations but very indicative (I think) of a loose sensor wire. Another factor is the recent RMS replacement just before I bought the car. The needle drop is getting more frequent. Where is the pressure sender located? Is it accessible without an engine removal or other major surgery? I am well versed in mechanics although I don't have time for elaborate repairs and haven't gotten service manuals for this car yet.

 

It is near the back of the engine compartment on the right hand side. Should have 2 wires coming into the top of it.

 

Again thanks. Found the sender and the wires are secure. Must be a connection problem elsewhere. Guess it's time for an appointment.

 

Also, it isn't a good idea to trust the dip stick on these car when the engine is warm, or you will overfill it.I always wait till my car has sat overnight to check it, as it takes a while for all the oil to get down into the pan in these cars. I rarely ever need to add any oil between changes, maby half a quart total throughout a 5k span.

Kevin

 

I had this occur once. I had "junk" in the oil pan that had clogged the oil pickup screen. Upon acceleration it would pickup the yuck and clog the oilscreen. When I would let off of the gas the junk would fall back off of the screen and allow oil to flow. Mine was clogged with metal shavings from the engine?

 

UPDATE. I replaced the sender (easy) and the problem has vanished. At a friends Porsche shop last week I saw a cutaway of the offending sender and no wonder it shorted / opened. It is an agglomeration of mechanical / electrical components not entirely unlike the pressure gauges Captain Nemo hand-built for his submarine Nautilus. The repair, for those interested goes like this. Take a real cheap 19mm (or 3/4") open end wrench, bend it (in a vise) about 60 - 75 deg close to the crows-foot end. Roll up right shirtsleeve to shoulder, open hood. Sender is one arms length toward front ("back" in Porsche speak) of engine compartment. Unplug wires from spade terminals. They only go on one way as the terms are different widths. Put wrench under cylindrical body onto hex portion of old sender. If you can not get the wrench on the flats, you may have to bend the wrench in the oposite direction (there is little room to turn the wrench and it will only work one way). Unscrew sender, screw in new one. You will undoutedly have to bend the wrench the other way during the tightening to get a decent crush on the aluminum seal washer. Hook up the 2 wires (they only go one way so don't worry). Close hood, wash hands, roll down right sleeve. This method allows you to brag about being able to repair your Porsche "with one hand". Thanks Rx for the help. Shortly, when I change the oil and filter, I will drop the oil pan just to make sure of no debris and proper function of sump doors.