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numbbers · Posted: Sun Jul 09, 2006 11:22 am Post subject: Oil Pressure Change

I changed my oil pressure sender today, because my OP guage was shaking. Thought I would let you know, that the OP changed from 8 bar at start-up, to 6.5 bar. My conclusion, is that the senders are not very accurate in sending actual oil pressure.
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1980 924 Turbo

Ozzie · Posted: Sun Jul 09, 2006 11:49 am Post subject:

My OP guage was jumping around occasionally but usually steady, just every now and then.
Then my OP light and brake warning light on the centre conole started flickering regularly.
I traced out the wiring back to the dual sender.
The sender was fine.
What was the problem was the heat shield/sound deadening material.
It was coated in aluminium foil type material and it was peeling off near the sender, effectively shorting it out.

As to accuracy? Some indication is better than none.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

tux · Joined: 02 Jul 2006 Posts: 133 Location: Nottingham UK

Bit of a digression here, but still sort of related (sorry to threadjack!) but I have noticed the oil warning light behind the steering wheel flicking on briefly if I am cornering "enthusiastically". I am guessing this is the oil in the sump shifting to one side so the oil pickup has nothing to draw from. Is this a normal thing with the 2 liter Audi unit or should there be baffles or something in the sump to prevent it happening?
Chhers peeps!

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Pete
Merlin Guards Red 1985 N/A

Ozzie · Posted: Sun Jul 09, 2006 10:09 pm Post subject:

Have heard of this happening.
Re my ealier post... the oil and brake light would flicker worse when cornering. May be related?
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

tux · Joined: 02 Jul 2006 Posts: 133 Location: Nottingham UK

Could well be related I guess Ozzie. Maybe a little exploration of wiring is in order.
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Pete
Merlin Guards Red 1985 N/A

augidog · Joined: 03 Mar 2003 Posts: 1360 Location: New Jersey

flosho · Posted: Mon Jul 10, 2006 1:37 pm Post subject:

I've noticed that my oil pressure is around 2 bar at idle after driving my car for a while and getting it warm... sometimes a little under 2. However this is usually when I have my lights on, when I turn my lights OFF the oil pressure needle will quickly shift about 3/4 to 1 psi higher, so at idle it'll be 2-3 bar w/o the lights.

lol I think 2-3 psi of oil pressure wouldn't get the job done!

[/b]
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[This Space For Rent]

seanski44 · Joined: 13 Mar 2006 Posts: 532 Location: Nottingham UK

as someone (Pete?) has mentioned before.. the guages, though still better than none at all, are little more than eye candy, as they aren't isolated from each other. when I was having alternator woes (hopefully they're all behind me for a while!) the oil pressure and volts would all be affected by any electrical item being switched on or off...

btw as for the oil light coming on, that doesn't happen to me, but I have the flickery 'brake' light at the mo.... checked the reservoir and all looks good, so hopefully its an electrical gremlin!
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1998 BMW Z3 2.8 arctic silver & red

1981 168HP 931 S2 blue/tan leather - SOLD

1985 121HP 924 2.0l na modded - SOLD!
1992 968 lux SOLD
1989 944 2.7 lux SOLD

Ozzie · Posted: Mon Jul 10, 2006 5:01 pm Post subject:

The brake (dash) light is connected with the oil light via a blue/black wire to the oil sender.
This allows the lights to come on b4 starting.
Also connected to the m/c reservoir.
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Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

924RACR · Posted: Mon Jul 10, 2006 9:58 pm Post subject:

Slam · Posted: Tue Jul 11, 2006 3:33 am Post subject:

My 944 oil pressure gauge would alter its reading when I turned the headlights on. A new ground harness wireed to the ground point behind the glovebox solved that problem. If you can't clean your grounds, run new ones and stand back and watch gremlins magically disappear!

Also, our 931's oil pressure gauge flickered at idle and within a month the car had spun rod bearings. Take your gauge's word for it if it's telling you your oil pressure is fluctuating. They may not be completely accurate, but a flickering needle spells trouble - providing, of course, any wiring issues have been resolved.
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'84 944 - kid blew motor
'83 944 - resting comfortably. For 12 years
'87 944 - sideswiped by trucker
'80 924 - gone
'78 924 - gone
'77 924 - rusting comfortably

Raceboy · Joined: 01 Mar 2004 Posts: 2327 Location: Estonia, Europe

Slam · Posted: Wed Jul 12, 2006 9:10 am Post subject:

Sure. I ganged a series of female spade connectors to a wire running to a ground point behind the glovebox (solder everything) where there's a factory ground point - at least there is on my 944. The female connectors just run to all the ground spade connectors on the console gauges and such. Because the battery grounds to the battery box, if the factory ground point isn't there, just pop a self-tapping machine screw into the sheet metal behind the glove box - it's right by the battery box and provides a good ground, as long as the battery negative cable is attached properly. I've also run another ground directly to the engine block, so I've got two coming off the battery - one to the battery box and one to the engine block. Works well - so far!
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'84 944 - kid blew motor
'83 944 - resting comfortably. For 12 years
'87 944 - sideswiped by trucker
'80 924 - gone
'78 924 - gone
'77 924 - rusting comfortably