Hello,

Link:
to give a quick back story I am completely new to the 350z Life.
Just purchased this 2007 350z Auto.. just about everything about the car is perfect with 101k miles. Underneath everything was original parts, suspension looked good car ran great.
The previous owner tells me I am over thinking it but, this noise is bothering me and i would love some insightt on it.

Basically when i first bought it i decided to run 87 without even realizing it needed 91.. I’m not broke i just literally had been so accustomed to filling up my civic with 87.
But i have never heard any type of engine knock or ping or whatever this is before, I have sine then refilled with 93 here in the states when i still had about a quart left of 87 in hopes it was just that.
But I’m hearing anything from “watch out bro your piston is done soon” , to valves, rod, tensioner ****..
So can anyone chyme I’m on this?

it just does it coming down from revs and when i am close to the engine i don’t hear it at all compared to when I’m outside the engine bay or inside the car.
also haven’t seen an affect on power and it is not continuous or follow the revs just kinda trickles after its lowering in revs.

oil is new in the car and air filters look fine..

thanks guys

 

Welcome- your VQ35HR was designed to use (minimum) 91 octane fuel. You didn't do your engine any favors by exposing it to detonation as the result of using regular unleaded. Depending on how long ago you purchased it, permanent damage may have been done. Any codes?

 

Bought it like 3 days ago, havent driven it hard on 87 at all, just a long trip back from where i bought it about 60 miles, and some light city driving, because I already knew of the lower MPG, but after realizing it needed premium i quickly switched over (today). I placed 93, the highest i could find immediately near me, the tank had about a quarter left of what i originally had put in. no codes, should i run to local auto parts to see if there is any stored or anything like that? Check engine light comes on with ignition on but once the car starts it goes away like regular.

Thanks for the quick reply

 

DK is correct that it needs the highest octane you can find but I wouldnt worry about the 87 in there ... the ecu will detect knock and retard timing and furthermore flip a CEL if it's outside the standard operating parameters.

I have no idea what that sound is other than not normal ... I'm not nearly good enough to diagnose over a youtube video.

Was this noise present during your initial inspection & test drive?

I'd try to get ahold of the previous owner and start talking about splitting repair bills ... likely he is going to tell you tough-luck and you're likely looking at some engine repair work.

Have a few 3rd party/independent shop look at the car and get a better idea of what's going on. Analyze your options and do whats best once everything is known.

 

So far the PO has been great as far as still communicating with me . I guess I will have to take it to a proper independent shop because his response was “They all do that, that’s the exhaust flow on the hr and vq engines” and also to just put higher octane fuel.

Someone else told me my piston is going to blow

someone else said like it could be motor related it could not

so now I’m just nervous I can afford premium all day but not motor work..

as for when ive heard it, I’ve been hyper sensitive to all noises since I just bought the car, there was a noise coming from the headlight just because it was loose. I can say that I didn’t really notice that particular knocking noise when we inspected it and I did rev it from park as shown in the video during inspection. Trying to find a reputable Z shop in central Florida

 

The PO owes you nothing. Sorry, dude, but you either bought the problem or caused it yourself by not reading the owner's manual, which you should do with ANY car you buy - used or new. You should have had the car checked out by a mechanic before you bought the car and negotiated the mechanic's fee into the selling price.

Leave the PO alone. This is really on you at this point.

That said, we can give you guidance here, but not the kind of guidance you're going to get from a qualified professional who actually has his hands on your car to do the diagnostic. Don't be hyper sensitive about the noises and don't listen to unqualified opinions on what the problem may or may not be.

 

Hello everyone and thanks for those of you who replied with feedback.

Ended up bringing my Z to an independent Z shop and they diagnosed that it was my catalytic converter failing and starting to rattle. Better than bottom end nose or tranny, and was not at all related to pinging or spark knock. It was still in parameters thats why it wasnt showing a CEL but it couldve harmed my engine in the long run so I got them replaced with some HiFlo's

 

I agree with you but assuming the previous owner isn't a complete douche 'might' (and I say that loosely) work with the OP ... you never know the discussion they had before the sale ...

regardless ... I hope it works out

 

Glad it woked out, OP.

bealljk - I totally agree with you on hoping that you're going to get some kindness, but in the end, unless there's a written warranty involved, the seller should be allowed to walk away from the sale and never talk to the purchaser again. For better or for worse, all's fair in love, war and used cars.

 

yea, if it aint in writing it never happened - all is fair in love, war, and craigslist!

some new/used cats is way better than a new engine!!