Engine Oil Pressure Low

[nehmaiz]

HI every one,

just wanted to ask if any person has encountered this problem before.

while driving and usually after an hour or so, the "ENGINE OIL PRESSURE LOW" signal starts to appear in the dash with an alarm sound, i refered to the owners manual which said to stop the car immediately after this signal is shown. so i took it to the local dealer and they checked it, he said everything is fine and that they dont know what is causing that signal and that i shouldn't be troubled unless i hear a wierd sound from the engine (quite reassuring :S )

now after 6 months, this signal has become part of my everyday driving scenario!!! as i noticed it lights at specific places, like an uphill or sharp corner! and ever since i feel the cars performance has dropped down a notch...

anyone know anything?

[system-s]

I faced the exact same problem few weeks ago.
What i did is that i changed my oil and oil filter, after few hours the signal went off and everything was fine again.

[nehmaiz]

this problem has been happening for six months now, i've changed the filter almost 3 times and oil 6 times!! i dont think that's what is causing my problem...

[kazyee]

most likely a sensor.... check gasket around the oil cap and make sure it seals correctly.... and make sure your not leaking... also make sure there is no sludge that can mess with ur pressure as well.

[klost]

I have a 2001 and have the same problem. I had it to the shop several times and had a sensor repaced and it continues they dont know why. It happens on hot day after a 1/2 hour or so only when at idial. Im looking at getting mechanical gauges put in. does anyone have any sugestions or recomendations ?

[rickyj001]

What type of oil are you using i.e. what weight? 20/50, 10/30, 5/30?
What are your ambient tempuratures like? High 90's F or low 30's?

I assume that your oil level is never low enough to cause the light to come on?

If the oil pressure sensor is doing it's job, you should not see the light come on until the oil light reaches it's low limit. I'm not sure what the limit is but for the sake of argument let's say its 10 psi at idle. This low pressure can be achieved by high ambient temps and the engine at idle which causes the viscosity of the oil to drop. If that's the case it may simply be an oil pump that is losing some pressure due to wear. How many miles on the engine?

The way most sensors work is they seek a signal to ground i.e. the negative side of the electrical circuit. Some will turn the light on when they have an open connection (no ground) and some turn the light on when the have a closed connection (grounded). I suspect that your's is the former and that what is causing the light to come on is a lack of good ground either from the sensor to the engine, the engine to the car's frame or a combination of the two.

To troubleshoot, run the car on the road near home until the oil pressure warning light comes on, then stop the car and let it idle. Open the hood and using something like a pair of jumper cables or any long wire with alligator clips on each end, connect any piece of metal of the engine block to any piece of metal on the car's frame. See if the light goes out. Also attempt to jumper from the negative side of the oil pressure sender to the engine block or car's frame. This may take some investigation to find which terminal on the sending unit is negative. Use caution as you don't want to accidentally ground any positive terminals and fry some delicate electronics.

I wish I had access to the schematics for the car, as that would provide more info as to how it's wired...

Good luck and let us know how you make out!

[nehmaiz]

hey ricky,

the answers to ur questions are : yes i use mobil 20/50 engine oil, and the car has 170,000 KM on it (oil pump never changed during 6 years).

i would say my ambient temprature is in the high 90 (degrees) when the engine oil pressure signal goes off...

anyways i'll try out that wiring technique u described,

thanks a lot for the usefull info.

Nehme

[WPC80]

Hello There,
I have this fault on my Audi 80 2.8.
I have tried everything i think of, next stop is the loom.
i have changed all the sensors, fitted a mechanical gauge, 75psi at idle and 100psi at 3k rpm, and it is at 3000rpm the signle is being activated then when the revs drop the warnings start. There is nothing wrong with my car yet Audi refuse to admit there must be a fault somewhere.
i have swapped the senders, shorted them out, run new cables from senders and still this problem remains, i can only assume now that the ECU is bonkers.
the only thing left to do is poke the sounder with a large hammer and rip out the oil pressure lamp
regards
wpc80