oil pressure sender problems (autogauge)
 

done a search but still not sure

just fitted a set of autogauge stealth gauges to my my00 impreza,boost works as it should do,took the oil temp reading off the bung above number 3 cylinder,a bit fiddly but again that works well...now my problem is the oil presure gauge,got the adapter hose from lma so i can use the original take off point under the alternator,not really too happy with the position of the sender as in order to lower it enough to clear the bonnet line the braided hose is at a bent angle as the coolant header tank on my car will not allow it to lie out of the way,but anyways my main problem is that the reading does not appear to be right,turn the ignition on and the gauge shoots straight round to the end of the scale 100 psi....earth problem i thought,so added an earth to the extension pipework and the gauge now stays at zero when the ignition switched on,so far so good,now when the engine is started the needle goes up to around 90psi,rev the engine and it rises to almost 100psi,then stays there??? there does not seem to be any movement relative to the actual oil pressure in the engine,turn the engine off and the needle does now drp to zero with the added earth attached,now questions...

1 has anyone else experienced fitting problems with the pressure sender and the lma hose on my00 cars as the header tanks do seem to be different from installs ive seen on older cars

2 is the extra earth actually needed,or have i a duff sender,as ive not noticed others mentioning this before when they have installed these units

3 how actually should the oil pressure gauge behave? i would believe that it should rise and fall in relation to the extra oil pressure produced when th engine is revved,or is it constant and only alters as the temp increases and the viscosity changes??

thanks for any help on this

well went for a drive this afternoon and the oil ressure gauge went straight up to around 100psi from cold,as it was when i fitted it,but as the temp increased a funny thing happened...the gauge appeared to work properly,at idle at 80 degrees it was registering 55psi,rev the engine and rose up to around 75-80psi then dropped back down to 55psi on idle.drive the car and it rose back up to near 100psi si im thinking as the oil temp inrases and the oil thins out a bit the pressure drops,makes sence to me anyways,can anyone just confirm this is how its supossed to be?

oil pressure is created by the pump trying to force oil through galleries and out of little holes throughout the engine. so as it thins it'll go through the holes easier hence less pressure :)

nothing to worry about - exactly as you have found, when cold the engine will always show pretty much max pressure with little movement
as the engine temp rises it will "drop" to around 2-3BAR at idle whilst holding 5-6BAR under load..............

seems totally normal from your description

alyn

cheers guys

no problem
 

yeah i would agree to the previous thread. i have exactly same scenario with my 1997 wrx wagon. it's perfectly normal

no problem
 

yeah i would agree to the previous thread. i have exactly same scenario with my 1997 wrx wagon. it's perfectly normal

Mine does the same, sits at 110 psi on idle.....but it was idleing for about 15 mins and never moved, do you think it will when I take it for a drive? (cant try yet no tax and a broken arm lol )
PS old thread I know but this is exactly my (problem?)
Lee

You can only try, mate. If it doesn't work, come back.
PS: old threads are worthwhile.

I know yeah it's the only one I can find that's spot on, lol Im not sure if the sender is fooked cos it's not worked since I bought the car, but the wiring was all to cock, 3 wires? :brickwall:wonder: lol anyway wires sorted but the sender is on a sandwich plate, been looking at the other sender( near alt) and not sure how it would fit/work ? My sender has just got one wire from the gauge connecting it.......:confused:

If it's on a sandwich plate, iot's worth cHecking if it's earthed.

Many need an earth through the engine block and bodywork, etc, and sandwich plates may not provide this.

Try touching a wire from battery -ve to the BODY of the sender, get someone to watch what it does.

Oh, and get it in the correct place once you have got it working: it either replaces the original oil pressure switch, or goes on a T-piece to it, if it's too big to fit there, or you want to retain the o/p switch.

My o/p switch has been on the garage shelf since fitting Defis six years back.

im going to fit my gauges when im off this week will the oil pressure sendor fit into the hole when i take the old switch out from under the alternator or will i need the braided hose not bothered about keeping the oem switch cheers

Depends on the size of the sender unit, thread size is another thing to consider.

Oil pressure gauge
 

Iv fitted an oil pressure gauge today, wired it all
up but use the two post sender that was left
on the, it just reads 100psi all the time the gauge came with
a one post sender would this be the issue
or have i done somthing wrong, any advise would be
great thanks. Grant

What sender is it wired to? You can't mix sender and gauge, you need to use the sender that came with the gauge.

Another tip is to start another thread with a question, you'll get more replies.