Hi!
Just a quick question: when there's knocking in the engine, when do you notice it? during start-up or while driving? Thanks a lot guys for your help!

 

When the engine is working hardest, such as, going up a hill...I suppose it could happen when cruising at highway speeds...but from what ive heard its when the engine is pushed harder.

 

going up a hill at the speed where the transmission wants to down-shift. if it doesn't knock then it's not going to

 

this could be a result of cheap gas if you pump a low octane gas...

 

2005...2400 miles...knockity knock knock!

 

?

Everyone should be running 91+

 

well mine doesnt knock when Im accelerating. Its just that there are times when I start the engine in the morning, it has kinda a rough sound. But during the rest of the day, that doesnt happen anymore. wierd?

 

Neva ran into that.....try higher octane gas.....or do you switch different grades of gas often?

 

it will do that in the morning because the car has been sitting. it takes a few seconds to get the oil to lubericate all the parts again. thats normal on pretty much all cars. you have a problem when you cant hear yourself think over the sound of the engine.

 

Exacty what I was thinking... Low octane gas in a High octane car will cause valve chatter or valve knock.

 

thanks guys!! Ive been using Premium since Day 1. I guess its time for a visit to the dealership, just in time for my 15K mile service.

 

My owners 05 SE manual recommends 87 octane or higher.

 

Twice now I have had an issue where upon initial startup the car will 'shake' pretty badly (once when it was very cold outside and another time after not driving the car for a week)... I gave it a bit more gas and it then ran smoothly (I thought that the oil might have settled or something so revving it slightly might cause it to spread more quickly?). This hasn't happened in a while (and I'm still not certain of what it was), but never any engine knocking... I always use 93 though.

 

high octane gas. never, i repeat never use less than 91 octane. i never run less than 93 and my 04 max runs smooth as can be with 30,000 miles.

 

And if you are using mid-low grade gas, don't try and use additives like Octane Boost or some of the other Jet fuel products on the market, you'll fry your plugs or damage your injectors... Premium all the way...

 

Pingging not knocking.

 

STOP USING 87 OCTANE GAS!!!!!!!

maintaining a car has to include the gas you put in, not just oil changes

 

queenzkid Did you read his reply?

 

Most of my knock or tick comes from the AC system...or HVAC. The rest is just minimal. Nothing to worry about. It quiets down as the engine warms up. I am now running 93 octane and Mobil 1 synthetic and still get a few knocks...or ticks when starting up. Started getting hot out here in the mid 80's....now, the fan is turning on. No problems.....just fan noise. Guess it drownds out the knocks. Alot of engines do make noise though. Nothing to worry about. If you are running premium.....knocks should be no issue. Check the AC compressor....they all make noise. Just my 2 cents.

 

If its so important, why does the mamual recommend 87?

 

FUEL RECOMMENDATION
Use unleaded regular gasoline with an octane
rating of at least 87 AKI (Anti-Knock Index) number
(Research octane number 91).
For improved vehicle performance, NISSAN recommends
the use of unleaded premium gasoline
with an octane rating of at least 91 AKI number
(Research octane number 96).

 

Its clear that an octane rating of 91 or above will give improved performance. I do not think that means, however, that it is necessary for proper maintenence of the car.

 

I can't understand why someone would buy something like the Max and not want it to perform for what you paid for. IMO if $.20/gallon ($3.20/fillup) is too much why not buy an Altima or other car designed for the whopping $3.20 less a week?
"proper" is a broad term. I feel minimum is more accurate. I'm sure you will receive proper to equate Premium by most to all Nissan engineers/mechanics.

 

The point is that Nissan states that 87 is ok and higher octanes will result in better performance.

87 is fine for the car and engine and should not be the cause of knocking. If the manufacturer states that 87 is fine, then

87 IS FINE!

If people want to put in higher, thats up to them!

 

I don't have any knocking and never put anything lower than 94 octane gas. The "shaking" as some people describe it could be because you are going to slow for the gear you are in (even on auto). Punch the gas and it will be ok, or slow down (yeah right)...

 

People are serious about the max. Dont' even mention "cheap" and "maxima" in the same sentence or you will hear stern feedback. that said, i subscribe to the high octane fuel. step up your game man you have a maxima not a station wagon, alright?? represent at the pump

 

This is all correct -- it appears in your owners' manual.

I suspect the noise being heard is not engine knocking, but one of the other noises mentioned in other posts.

Engines knock for a number of different reasons including being under heavy load. I've posted a long series of notes on gasoline octane in the Fluids and Lubes section of this site. Unfortunately, these posts are no longer on the 2 pages that are shown on that site, but should be accessable on this link:

http://forums.maxima.org/showthread....oto=nextoldest

You will obviously find more than you ever want to know about gasoline octane by reading all of my posts -- which I will not try and repeat here, other than to list the following:

Octane requirements are dictated by the following three engine operating factors:
- Cylinder Pressure,
- Spark Advance, and
- Engine Temperature.

Anything you do to increase any or all of these three factors will increase your engine’s octane requirement. So, if you put a turbo-charger on you car, you will increase cylinder pressure. If you’re driving a loaded car up a steep grade at high speeds, you will increase the engine’s temperature (but also slowly decrease the cylinder pressure due to ever higher elevation).

 

I get a "sewing machine" sound at idle at any temp.

 

Knocking....
It could be a bad coil pack.
When your voltage regulation drops it’s hard on the elec system and it knocks. A bad coil pack sounds like a catalytic converter going bad.
A service tech could run dio on it to confirm or dismiss. Good luck.

 

I've visited my local dealership for about 8 times to verify the source of the noise. Each time I left the car for them to check, they weren't able to reproduce the noise. Finally I took it in when I was hearing it loud and clear and took one of service managers out for a ride to confirm.

He said it's highly probable that it's due to shorter rocker arms in Nissan engines, which was designed by Nissan in order to lower gas consumption.

The knocking sound from my car only happens at 1600 RPM and is coming from the engine compartment, and it's most apparent when it's relatively cool outside with engine warm.

I'm going to try another dealership tomorrow to see if he's got a different opinion.

 

Here in the south (Tennessee) when it is hot (mid 80's and up) I was told by the stealership that it's the water pump..now of course this was not in a Maxima (still waiting for mine) but my 04 GT Mustang does it as well as my 04 Ranger.

Now in terms of the 91 octane, like others have said, why buy a performance car and put crap gas in it? To me that's like putting 87 in a Corvette. 87 in my Mustang makes a big difference power wise than 91. I did that once on accident and will never do it again. That mustang made all sorts of noise and accelerated like junk with the 87 in it.

 

The VQ35 engine is among the most advanced in the industry today. It is substantially more sophistocated than the 04 Mustang or 04 Ranger engines.

Nissan recommends 91 Octane or better but advises that you can successfully burn 87 Octane -- believe them. You will not get "all sorts of noise" and the Max will not accelerate "like junk." How do I know -- because I have done it. My Max has never seen WOT (thats Wide Open Throttle) and I don't race her. If I did either, I would be burning Premium. I don't need it -- and have rarely used it. When I did, I noticed no difference in the street performance that matters to me.

 

Went to the other dealer and they recommended premium gas. I have been switching from 87 to 91 back and forth, and I was able to hear it still with premium gas.

What I did was change to 91 Octane and no more going back to 87 for the past 4 fill-up's and it fixed the problem. No more tick/knock/clicking noise.... It's gone for good.

 

Whatever works for you. I suspect you have deposits in your engine that cause the light pre-ignition you hear with 87 octane. If you keep the deposits away by using a good fuel injector cleaner like Chevron's Techron, you may not have the noise you hear when burning 87 octane.

Every engine is slightly different, and yours may not tolerate 87 as well as mine does. You certainly don't want to consistently drive with light engine knock occuring.

You may want to check our more about Octane in the Fluids and Lubes section of this site. Go to my detailed posts on this thread:

http://forums.maxima.org/showthread....6&page=1&pp=30