1st944

I purchased my 944 about 2 weeks ago, not running. I was told by the previous owner it needed fuel work because it had not been driven in 3 years. I replace most of the fuel system and finally got it running today! I took a couple easy drives to see how everything was, and to my surprise, every thing was working great! The car idles perfectly, makes great boost, etc. so i get on it alittle, ( i couldnt resist), and it was great. I could not believe the power and how smooth it was, there were no dips in power, no hesitation, the car ran and drove almost perfect. Then i ran into my first problem. As i was taking the car for a short drive, i noticed the oil pressure gauge jumping alittle. Until no it read about 2.5 -3 at idle and around 4.8 - 5 at crusing rpm. From what i have read on the forum this is what it should be. Then as i drove alittle more the gauge dropped to 0 and was not reacting at all. I am guessing it is a faulty sensor, but i am new to the car and not familiar with it yet. If anyone has any suggestions on what it may be, it will be greatly appreciated.

Thanks
Roric

1st944

Oh yeah i forgot to say, once the car sat for a minute or two i restarted it and the pressure was fine again. I drove alittle and it occured again. Back i went and parked it. Later in the night i started it again and it was fine, i took about a 15 minute drive and it didn't happen again.

Roric

PorscheDoc

I would vote for bad oil pressure sending unit. You will need a stubby 15/16 or 24mm wrench to get it off, thin head is better (i took a really old crappy 15/16 wrench, cut it in half and ground it down a little for a custom tool ) . Mine was tight as could be and i couldn't budge it, so i got a 240lb "Mongo" to pull on it and get it broke loose for me. Course he broke it loose like it wasnt even on tight...bastard. Its down on the front passenger side of the vehicle..has 2 wires going to it. Oh you have to drop the power steering pump off it's mounting brakets with the hoses still attached, and hang it out of the way for access.

edit
Or it could just be a bad connection to the unit

Jeremy Himsel

I'd say that the oil pressure is probably fine. When these cars lose pressure the lifters tend to be really loud. In addition to the sending unit, check the wires coming off the sender as well. If the car has been sitting that long, some of the insulation on the conductors may have cracked off and is intermittently grounding against the block. The wires loop up and around the top of the waterpump. A third option is the oil pressure relief valve is sticking on occasion. Check the sender and the wiring and go from there. BTW, your oil pressure numbers seem right.

mochman

Change your oil see what it looks like, if your pressure does go low you'll know it, make sure the crank nut is tight.