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SouthBay · Joined: 04 Aug 2004 Posts: 9 Location: Northern California

Anyone else having problems with this? The moment the key turns, the oil pressure guage pegs out and stays there. I can't imagine it being anything but a short or a bad guage/sender. Anyone have a suggestion for where to start?
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1987 924S

Lizard · Posted: Sun Mar 20, 2005 8:07 am Post subject:

model and year?
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3 928s,

Paul · Posted: Sun Mar 20, 2005 8:35 am Post subject:

As long as your oil light is not staying on, don't worry. Most 924S's oil guage's read 5 at start up, but at idle it should drop to around 2. Check the wiring on the oil sending unit which is underneath the oil filter. If the wiring is good, it may be time for a new sending unit (about $70 US).
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

SouthBay · Joined: 04 Aug 2004 Posts: 9 Location: Northern California

Sorry, '87 924S. Unworried, but it's annoying: ) I'll play around with the sender wiring, that seems likely.
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1987 924S

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

I had this problem with both my 77 924 and 81 924 when I initally purchased them.

Both of the cars had previous owners who were not that interested in scheduled maintenance.

What happened is after a number of regular oil changes, the oil pressure gauges started to wroked correctly in both cars. I suspect that what happened was the tiny oil passage in the pressure senders became clogged with debris acting like a one-way valve. After regular oil changes the detergent in the oil broke down the crud, and allowed the oil to move freely through the oil sender, curing the problem.

Don't forget that the oil pressure will also be higher when the engine is cold.

CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

Quite likely that the sending unit's wires have gotten attached backwards (don't ask how I know this...). There are two posts on the sending unit, one for the idiot light, one for the gauge. If you hook up the light wire to the gauge post and vice-versa, the gauge pegs-out and the pressure light glows as soon as the key goes to the ON position, and stays there.

I put different types of connectors on the leads coming off the sending unit so I couldn't mix them up again.
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'79 Eurospec 931