924Board.org

Andre'

Hi guys,

any advise on this one? Turned on the ignition after reinstalling A/C evaporator unit below the dash and replacing the dash with a new one, and the oil pressure gauge pegges out full. Bad sending unit? Bad gauge? The battery tray has been replaced - could it be the fact that the car has been welded on? How do I determine what's wrong here?

Thanks, and happy Labor Day to all!

Andre'

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

You need to get a mechanical oil pressure gauge to test and see what the real oil pressure is.

Could be a gauge problem or could be an electcial problem you caused when you had the dash out.

This is the 924S Section, and if you really have a 924S, you could also have a sticking OPRV (oil pressure relief valve).

Do not start the engine or drive the car until after you have this problem diagnosed. A failed OPRV is a serious problem that could ruin your engine.

Andre' · Posted: Sun Sep 06, 2009 11:31 am Post subject:

Thanks for the advice. It is a 924s, and everything was just fine before I took everything apart. Therefore, I believe its just some kind of electrical issue but I'm not sure. I do have a back-up gauge; I'll measure the voltage/amps to make sure I won't blow it for whatever reason. Do you happen to know the location of the sending unit?

Thanks!

Paul · Posted: Sun Sep 06, 2009 12:34 pm Post subject:

Underneath the oil filter.
_________________
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.

John_AZ · Posted: Mon Sep 07, 2009 9:23 am Post subject:

When you replaced the dash, did you switch the wires on the dash guage?

Normally when someone installs the oil pressure sender on the engine and the wires are reversed--------------the dash needle pegs to 5.

GL
John_AZ
1988 924S + 1987 924S

Andre' · Posted: Mon Sep 07, 2009 1:24 pm Post subject:

No - didn't switch the wires. Just unplugged the gauge and hooked back up during reassembly. I've already checked the wires - they connect correctly. I'll check the gauge tomorrow by installing in my back-up 924s.

Thanks for your help!

veewdriver · Joined: 17 Jul 2007 Posts: 6 Location: Tucson, AZ USA

The "project" I just picked up does the same thing. I haven't started the car yet, but when I turn on the ignition, I get no oil warning light and the gauge pegs on 5 bar. Let me know what you find out, because it seems we have the same problem.
_________________
Tom in Tucson

Currently:
88 Red 944
81 Silver/Grey 924 Turbo
Past:
87 Black 924S
79 Red 924S (M471 options)

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

If the car isn't running and the oil pressure gauge pegs to 5, it can only be one of two things: either the wires have been reversed at one end or the other, or there is a ground fault in that circuit.
_________________
erstwhile owner of just about every 924 variant ever made

veewdriver · Joined: 17 Jul 2007 Posts: 6 Location: Tucson, AZ USA

Paul · Posted: Fri Sep 11, 2009 9:22 am Post subject:

A bad oil sender or gauge can also cause this. On the white ghost it was the sender.
_________________
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.

Andre' · Posted: Sun Sep 13, 2009 11:17 am Post subject:

The wires are definitively not switched! Just unplugged the gauge, swapped the dash, and reinstalled everything! The gauge is fine - I've checked the gauge in another 924s. I think the sender must be bad for whatever reason; I'll swap sending units to find out.

Thanks everybody!

Andre' · Posted: Sat Dec 26, 2009 8:34 am Post subject:

Bad sender - problem fixed!

Paul · Posted: Sat Dec 26, 2009 8:46 am Post subject:

Merry Christmas!
_________________
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.

Andre' · Posted: Sat Dec 26, 2009 9:17 am Post subject:

Thank you! Merry Christmas to you, too!