oil pressure light

[aidannorris]

guy's

my oil pressure light is constantly on, i have no oil leaks, no oil in the engine bay, and plenty of oil in the motor. i have a 02 GU 4.2TD.

I have had mine next to another GU and done comparisons between the 2, both have current going to the connection to the sender and with both connections pulled off the sender my light stays on and the oth GU's oil pressure light goes off when started. i have checked and re-checked all the fuses and all seem to be fine.

I recently installed a CB and a CD player which knocked the lighting to the tail lights and dash out, the auto elec said it had to do with something to do with the earth returning the wrong way (not 100% sure what he was talking about though) but all is working now.

Any help would be appreciated

Aidan

[marko]

swap the two oil pressure senders over from your mates car

[aidannorris]

but wouldnt the fact that i have had both connections off say that its not the actual sender?

[Ibsn]

I would be checking all the earth connections, because I believe if an earth is off, It can back feed voltages down the wrong circuits, and cause false alarms, as in the oil light comming on.

(im in the middle of having issues with lights on all over the dash (but dull) and only when i just started it up, giv it a few revs to bring the voltage up that tiny bit and they all fade away) as a consequence of this fault the alternator is not charging the battery correctly, as its not sensing the voltage difference correctly - its confused the hell out of me- What the hell!


HOWEVER I would make dam sure your actually getting oil pressure up into that motor before your running it for more then 10 seconds. I would start by getting an oil pressure meter (30 bucks for a cheapie from supercheap) on your dash which goes in parallel with the oil pressure sender on the side of the block, Just buy a brass T piece. which You usually get in the meter kit,

I wouldn't trust a 10c light in the dash to tell me my TD42 is pumping oil around while I try and figure out if its an electrical fault, or a pump failure, Or you will end up with a seized hunk of metal!!!!!

[Ibsn]

but wouldnt the fact that i have had both connections off say that its not the actual sender?

Also, depending on how the thing is wired, Who knows. BUT It might require a voltage at the sender and at the light, as in closed circuit to turn the light off.

therefore in fault conditions, the light will be on whether or not the oil pressure is low,

THIS means that in any event your safer then sorry, imagine if you cut the wire on the sender. There is no current flowing to the light your saying? wrong, If the pressure was low, or the cable fell off the sender, you would want the light to be on, even though the cable is not connected.

I dont know if that makes sense, But in any event, in a fault, the circuit to the sender goes open. or the pressure is too low, (it might go open circuit) open circuit usually means there is no current flow (which would be tiny tiny current) HOWEVER your light turns on...

which makes me think, that it needs voltage, to keep the light off... because under any other condition other then pressure present, the light will be on!!

so what im really trying to say, is, yes, i have no idea what to do, car electrics is mind blowing..

and or only just thought of this, short the sender connections together (IF THERE IS ONLY ONE CABLE< short it to earth!!!? if that puts the light out. Then try your mates sender, if that seems to work correctly, then buy yourself a new one.

trouble shoot and eliminate.

hahah i only just thought of all this. You owe me if it works :p

[benhl]

Are you sure it's an Oil Pressure light???

LOL