I've been having a strange issue.

2006 350z GT 6spd w/revup losing oil pressure at idle (18-25psi) and pulsing when AC is turned off and drops to 400-500 rpm. When AC is on idle returns to pulsing at about 28-30psi and 600-800 rpms. Also when the oil pressure drops it seems like the car loses a little power and the interior lights dim a little bit like it is about to die but bounces right back up and starts pulsing low again.

HERE IS A VIDEO - In the video the pressure gets pretty low, but sometimes it goes even lower.

I'm running 10w30 Royal Purple and have been for about 2000 miles. The car was running fine until about a month or two ago when I was sitting in a drive through and noticed the engine starting to knock. I checked my oil level and it was only a quarter of a quart low and I filled it up. The problem has persisted which leads me to believe it is not low oil, especially due to the fact that it maintains normal pressure when there is a load on the engine.

It does it when the engine is cold & warm which makes me believe it is not the weight of the oil causing the problem.

The car only has 68k miles which makes the oil sending unit seem like an unlikely candidate.

Any insight?

I would like to maybe pinpoint some possibilities that might be easier to test before I take the oil pan off and start dropping some serious cash.

 

First of all RP oil is crap
Second you need 7psi per 1k RPM
Third, you probably need a tune up or MAF cleaning, maybe both

 

holy **** is ur z a hybrid?

 

I'm on a 2004 G35. My cold start will put my oil pressure at about 25-30psi but once the car is warmed up it will idle at about 15psi. At freeway crusing speeds I see 60-80 oil pressure.

I also have a knocnking sound but mines is at slight load between 2-3K that has been around for some time now. I'm boosted (s/c) and I'm not losing any power but I do go through like 1/4+ quart every 3k miles. My car has been retune recenetly, my tuner can't seem to find the knocking sound and the car is making great power and all. So i'm just writing it down as engine noise until I start to see smoke or loss power.

I would check the voltage on your battery maybe something is loose or you need a new battery.

 

I've run Royal Purple in every sport vehicle I've ever owned and never experienced any issues from s2000, Prelude, and two 350z's... So I doubt it has anything to do with the brand of oil causing an idle issue but I do plan on changing back to 5w30 before I head to the ZNationals in a few weeks & it starts getting colder out so I might go back to Mobil1.

What could be the correlation between MAF and low oil PSI?

 

Haha no. I do get 20mpg in town... 6-spd and attempted good driving habits. I do get 27mpg on the interstate and I had just reset my guage on a 180 mile trip to Louisville and commute to school several times a week so it stays up there.

I also just replaced the battery when I purchased the car earlier this year.

The weird thing is how the idle and psi change when I turn the A/C on or off. But I guess it is due to the extra load on the motor at idle.

 

Your oil pressure and RPM reading is NORMAL..period end of story.
My 08 PSI reads a tad lower than yours at idle with AC off. Normal according to the manual is 14 lbs at idle.

 

When the oil pressure drops the engine knocks. That is not normal? But I did look it up I had just been going by what my oil pressure has previously sat at (30psi) and readings should be 15psi at idle. So maybe there is another underlying issue causing the knocking and loss of power.

 

^this. its normal mines the same if not lower, 08

i dont think ur car is knocking maybe its almost stalling, search idle reset procedure

 

Royal purple is not crap. Wtf are you reading. Its the only oil am soil won't compare itself too.. now you oil psi normal. The MPG should be average that's what I get and I have 14x,xxx miles on mine. I'd prolly clean you iacv seems like your rpms takes a little long to come back up when AC is on it may be sticky..

 

https://my350z.com/forum/engine-and-...-and-info.html good reading

 

LOL I thought the engine was off, my Z isn't that quiet..

 

The pressures seem normal, and yes you are correct about increased idle RPM when the A/C is on. The increased load bumps up to idle. If you can try getting a sound clip of the knocking it would be more helpful. Also try connecting a scan tool and see if their are any pending codes that could possible go along with the problem. Also in your OP you say that it is an 07 but rev/up motor. Was that a mistake or...because I always thought 07+ were HR.

lol, please show me where the IAC valve is on these vehicles...

 

 

I've ever owned and never experienced any issues from s2000

 

From what I understand, RP is a pure race oil. There are no detergents to suspend the crap your engine produces and it does nothing for a DD except dirty up your engine and cause excessive wear. Unless you plan on changing the oil every few times you drive it you're FAR better off with a normal detergent oil...

 

thats cool, to bad ur slow

 

Now you've got ME confused. Maybe it is a 2006......... Because I thought I remembered it having the Rev-Up that was one of the reasons I bought it. And yes... Now that I think about it, there is not a raised hood. I looked at so many I must have gotten the years mixed up over time. But yes you are right the 07+ is HR. I'm the idiot here.

I cleared all the codes out recently and no CEL or pending codes anymore. Previously it did have some codes when I purchased the vehicle, but it also had really old gas in it and a dead battery that had lost power for quite some time. I remember something about low voltage or output. It also idled extremely high until I reset the computer. I bought it for $5k needing a new paint job, camber arm, & wheel... and redid the entire airbag system but haven't plugged it all back in yet.

 

Sorry I thought it was the oil pressure, I had just always seen a higher oil pressure and never experienced the idle issue. When the oil pressure dropped I merely associated it with the horrible sound from under the hood and assumed it was too low for the motor. However, it seems there is another culprit involved here. I will try cleaning MAF and other sensors and probably switch to 5w30 Mobil 1 just in case. Through deductive reasoning I will eventually find out what the real problem is...

 

Not true.. they do make an oil like tho. Its xpr or something like that..