Low oil Pressure = Bad performance

[Fox213506]

My z has some sort of fault. I have noticed that my oil pressure gauge shows that my oil pressure starts of good ends up bad. I go to start it and it goes to 60psi for a while everything is normal. I start going down the road and pressure goes up when i accelerate and when i stop it goes down like it should. But after about 15 minuets of run time the pressure stays right near zero, i doubt its the gage thats faulty. when this happens performance suffers badly . when i go to accelerate, it stumbles to get up to speed. i dont understand, i did the motor swap, and this is the same problem i had in the blown engine i swapped. WTF!!. Please help, this is my DD and i cant have this problem. This is a 1994 N/A motor, 1990 Body

[freakonaleash1187]

The oil pressure is normal. When you first start up the car, the oil is cold and thicker, causing the oil pressure to be higher. But after your car warms up, the oil becomes thinner and the oil pressure goes down. And the oil pump is engine driven, so the oil pressure will change with RPM change.

[elwesso]

Yeah hot oil pressure should be around 15psi so if it seems low its probably about right. Nissan's let yo uknow if it has low oil pressure by having a rackety top end.

As far as the stumbling problem, have you checked for ECU codes? What did you keep from your other motor. What wasnt changed?

[Fox213506]

I dont want to say what was or was'nt changed from the other motor because i know i will get roasted by everyone. I still think theres a problem because, after the oil is hot and the pressure is low i can rev the engine and the needle wont move. Who knows i might take it to the dealer aftger i tinker with it a little. More help is always appretiated if anyone has an oppinion./

[elwesso]

First thing I would check is the oil pan because if theyre dented you can get low oil pressure because the pickup is super close to the bottom of the pan. See it all the time on Qs and Z32s because most of the time they set the motor on the pan and it dents it. If its dented then youll want to fix it, that could very well do it.

i dont think the lack of power is oil pressure related, if it was the case then youd be looking for a new engine.

I would start checking other things for the hesitation issue. MAF, fuel pump, TPS all the usual crap.

[Fox213506]

You are right about checking other things, the pluem and the fuel filter were all from the other engine maybe thats the problem. I will start checking that stuff tonight. Another thing i would like answered is how long does everybodys engine take for it to cool down. Don't these engines run hot? My engines takes a while even with the hood open. Next week im going to VA beach and im hesitant about taking it with us in the 9 car caravan. Im just afraid to blow the engine and to me it takes way to long for it to cool down. Is this normal. bear with me i used to have a honda and all this is new to me, this motor is something i have never had the pleasure of maintaining.

[elwesso]

on my Q45 it takes a while. That engine is really packed in there so its not gonna cool down real fast, plus its about 2x the size of your honda engines, so

Even with the hood up, my motor is still warm to the touch after 20 mins. If the temp gauge is in the middle, then its probably OK.

[freakonaleash1187]

The engine bay in our Z's are one of the hottest engine bays out of any car and they do take forever to cool down. It takes hours with my hood closed to get it cool enough for me to touch it.

[Fox213506]

Thanks guys, my temp gauge doesent read and i was worried that i was running the engine too hot. Ill try to fix it ASAP just to be safe!. Again thank you, you dont know how much this inforamtion is appretiated.