VERY low oil pressure...whats up?

[Jspec7m88]

hey guys, once again, another unsolved problem that wonders my mind...ive got a jspec7mgte...had it for about 2 months now, and ive replaced ALOT of things to make it fresh...including running a full-synthetic oil change <--first thing i did. ive recently changed my water pump, thermostat...and i noticed that my oil pressure is VERY low on my gauge...could it be a stock "dummy" gauge or is somethin up?...or is it just suppose to be like this? thanks in advanced.

Your MK3 brotha from a notha motha :icon_surp

 

[IJ.]

Low Oil Pressure at idle or at cruise or all the time?

More info please

 

[Jspec7m88]

when i start it from a cold start, it idles at like 1400 for about 30 seconds, then drops to about 1200 where it normally idles in park or neutral...but once in drive or reverse it drops to a "realistic' 950 or 1000 and is fine.

 

[IJ.]

I meant low oil pressure, not low revs.

 

[Jspec7m88]

i'm a dumbass...lol. when i FIRST start it, its very low, then once the motor warms up, it is still unusually low (really close to the big fat "O"). and when i drive it or give it some gas...it barely goes up...unlike before i did all this, there was a lot of pressure.

 

[IJ.]

How long since the last filter change?

 

[Jspec7m88]

umm, under 200 miles have been put on it...when i got the car, the 2nd day, i ran changed the oil and filter and ran full synthetic...now about a month and half later, i changed my water pump and thermostat...and that shoulD have nothing to do w/ oil pressure(i dont think),but this is when i noticed the oil pressure is REALLY low.

 

[IJ.]

What weight Oil was in it and what weight is the synthetic you replaced it with?

 

[Jspec7m88]

10W-30 for both

 

[JustAnotherVictim]

I'd check the wire to the pressure sending unit it's possible you may have moved it just my .02 for now

 

[IJ.]

Are you certain the old oil was 10/30?

If the old owner had 20/50 in it you'd notice a big difference.

Personally I wouldn't run 10/30 in a Supra but it doesn't get as cold here.

 

[mkiii222]

When I first got mine and ran 10w30 it would idle at about 10 psi or less and max at around 30.
Now that I'm running 20w50 I idle at 20 and max 50.

 

[Justin]

did you pull the JDM oil pressure sensor out and replace it with the USDM one?

 

[supraman7mgte]

Are you using the sender that came with the motor? If so,i'd swap it out with the one that came on the A spec motor.Might be a bad senspr.

 

[IJ.]

I'm assuming (dangerous I know) that he's got the correct sender as he said before the oil change he had good pressure.

 

[mrnickleye]

You would not believe how many times I've heard over the last 30 years as a mechanic, that "it didn't have a problem until some other work was done", not even related to the new problem. The guy said it himself, it started after he did the water pump.

So... first look at the wiring connection at the sending unit. If it is bad, repair it. It needs a good connector crimped to the wire, and a tight connection to the sender.

The reason 10-30w shows less pressure readings is that it is thinner than 20-50w. Perhaps the synthetic you used is thinner than 10-30w petroleum oil. You could drain the synthetic out (save it to re-use if you wish), and put in 10-30w regular oil. Does the pressure come up??? Yes? There's your answer.:icon_bigg

No??? Still got a problem ??? Do as a previous poster suggested, and try a new sender.

 

[JesseH]

I'd check the wire to the pressure sending unit it's possible you may have moved it just my .02 for now

That is prob. your problem, mine did the same thing a while ago, It would stay close to zero then go up a bit then drop to zero and stay there. It turned out the wire was loose on the sending unit. The unit is close to the oil filter, I would check that first

 

[aye mate]

That is prob. your problem, mine did the same thing a while ago, It would stay close to zero then go up a bit then drop to zero and stay there. It turned out the wire was loose on the sending unit. The unit is close to the oil filter, I would check that first

Werd I had that problem too.

 

[SidewayzSupra]

After I broke in my motor I started using 10-30 synthetic and also noticed low oil pressure(summer) My friend of mine told me to put in higher wait so I stopped using 10-30 and actualy went with 15-50 didn't want to go quite as heavy as 20-50. Noticed a good difference afterwards. Even though motor was rebuilt and tight it sounded smoother and I got a lot more oil pressure out of it. Thats all I ran until it got cold and then I went back to 10-30. As long as your seals are fine you shouldn't have a problem going back and forth due to seasons. Later-T