993 oil pressure spiking
 

Just picked up the new 993...looks great. But on the drive home, oil pressure was pinned all the way up - even after the car was warm. Looks like the previous owner hasn't had the oil changed in some time, getting that done early next week.

Any suggestions as to why this may be? My hope is that the gauge is broken/malfunctioning...

FWIW, Hot or cold, once I am off idle, my OP is almost at the top end of the scale. Been that way since I have owned the car, and no mechanic has said anything to me about it.

Different engine, obviously.

Thanks, Mike...hopefully that's the case. I'm used to the 73T and the SC where the oil pressure fluctuates w/ RPM.

Sounds like the oil pressure sending unit went south. They normally short to ground which will peg the gauge. WHen you turn the key to ign, but not start, does it peg? If so, that would be a short in either the sending unit or the wire to it.

That's normal for the 993, it will drop at idle. Depends on the rpm, but anything over ~2000 will have the OP at 5.

Hold on everyone, lets not jump way ahead. Need more information. First of all do you mean when you are on the throttle or all the time? IDeal pressure should be right aorund 2.5 or so and MANY 993s when on throttle are pegged. Now are you also sure that you are looking at the gauge all the way to the right? The one on the left is oil level and then of course there is also the oil temp. Oil level gauge is worthless and always pegs. Take a pic of your cluster and post it up here and we can go through what each one means and what to expect from each of them. This threw me off at first as well. Great car btw ;-)

yep, that's it. Thanks Tim

sorry gang, didn't see all the replies and certainly appreciate them. Yeah, its the second gauge from the left (and on the right hand side of that gauge) w/ #'s 0-5. Not the temp or oil level. As soon as the key is turned the needle spikes and stays at 5 regardless of whether I'm idling or on the gas...always spiked.

OK i got a picture off of rennlist. Notice the white faces and blingy rings :lol: :cool:

From left to right your gauges measure fuel level, oil level, oil temp, oil pressure, rpm, speed, and time.

Oil level - only useful for calibration of your dipstick. Only even remotely accurate when you are on completely level surface and oil is really hot. Find out what level is right on the dipstick and then check what the gauge reads to get an idea how out of calibration it is. Probably the worst gauge in modern design for a car. It often will only start to register below the highest point on the gauge and when you start getting down a quart+

Oil Temp - Start to worry when it gets past the 9:00 mark and the fan in front should kick into low speed when it hits around that mark and high when it gets to the 10:00 tick mark.

Oil Pressure - Acceptable pressure at idle from the 1.5-3.0 mark, although you prefer to see 2.5. Will hit and stay between 4.5 and 5 under throttle and come back down to the idle pressure when warm. Mine typically was in the 3 range when cold and dial down to 2.0 at idle. If it is truly pegged all the time, then you have a short somewhere. There are plenty of documented cases where different senders (same part number) will get you different readings.

Hope this helps.:)

Sounds like you have a bad sender.