ok so i have a few questions...
i bought my z32 about 2 months ago and its had its share of mechanical problems. the injector was the main problem but after that it ran fine. then came the mufflers. the tips were braking apart so bought new mufflers. had that set up. but now that i drive it, it seems like there's less power. and the mufflers don't sound as good since i had them installed.

1) is there something wrong with the mufflers? (they used to roar, but now they sound muted) i thought maybe the welding wasn't done right. it roars from the left side, then it sounds like the right pipe is farting its way out.
2) i also took my car to a mechanic. it was having some engine issues. before i took it to him, the psi rating was at the middle or it would stay below. now that i drive it, the level stays high (for example: when i drive it and switch to 2, it gets very close to the 120 mark or if im driving on the freeway and have it on 5th it sticks in between the max and 90)

i appreciate all the advice given. thanks

 

did somebody put 20w 50 in it? you need to change the oil and put 10w 30 or 40 in it immediately. if the oil is thick enough to get that pressure, it's too viscous to lubricate properly. and stop letting people work on your car. mechanics are not good.

 

thanks. ill drain the oil and put mobil 1 synthetic 10w 40 ASAP
i knew it wasn't normal in the first place. ****ing mechanic was like, well its supposed to be in the middle.
i was like yeah right ok.
thanks again for the advice

 

General rule of thumb - about 10psi oil pressure per 1000rpm.

 

i get that you said general, but does that mean it's seriously safe to be under 10 lbs at idle?

 

As long as there is some pressure at idle, you're usually fine. (And for the record, the Z32 should idle between 750 and 850 rpm, which would be 7.5-8.5psi, by this standard.) The whole purpose of oil pressure is to make sure oil reaches everything it needs to reach... when the engine isn't moving quickly, there isn't as much friction, and thus less lubrication is needed.

 

ok cool.
so these mechanics dont know what they are talking about when it comes to a 300ZX.

 

Replace the oil pressure sending unit... they're considered a faulty part on the Z32, in general.

 

mechanics never know really. i've obsessed over this car for several years and i still don't know enough to run a z shop.

 

alright.
so the best thing to do is drain the oil and put 10W 40.
and see how that works out.
if its not that then i will reply.
thank you guys for the tips.
i know it takes time and money to keep these cars running strong.
thanks again

 

ok. so i changed the oil to MOBILE 1 SYNTHETIC 10w 40. It seems to run smoother, but the PSI increases still. Its not as dramatic as it was before, but it is still not normal. :/ dunno what to do??? spent about 50 bucks for oil. and changed it myself, but still...grrrrrrrr

 

i'd stop driving it until you figure it out. do change the pressure sending unit though. as said, regularly faulty and pretty cheap. you can consider your reading with the new unit fairly accurate and we can go from there.