'00 max Mechanics Can't Solve.HELP. Rattle/Whiney

First, you should be running 90 octane in it. Second, check the shields around your exhaust system. They come lose and rattle.

you need to use the proper recommended fuel - 91 grade premium.

otherwise its going to pre ignition rattle like an old sowing machine.

Which would mean the knock sensor is not sensing. If you are not getting a code from it (have to check with a code reader, the KS does not light the engine light), then it has failed in a mode where it thinks everything is fine.

Even though 91 is recommended, the car is designed to also run on regular without thrashing itself to death. The simple test is to run several tanks of 91 through it and see if it minimizes the problem. If so, then replace the knock sensor. I have heard that many times the problem is in the wiring rather than the sensor itself.

Other possibilities, though more unlikely:

- a failing timing chain/chain guide. It will also make noise out of gear at certain rpms if this is the case.

- loose /rattling exhaust shields. Easy to check. Just poke them with a broom stick.

- I had an old Altima for a while that sounded like it had a timing chain rattle. Turned out to be the accessory belt had thrown off enough chunks from the ridges that it made that same rattly zingy noise as the belt moved through the grooves in the pulleys.

- don't overlook the gazillions of other sensors (O2, MAF, etc.) that feed the engine computer the data it uses to adjust timing and mixture. Most of these will throw a code and like the check engine light, but there could also be wiring problems that are tricking it into thinking everything is fine.

- Have you tried running some top end cleaner (Sea foam comes to mind) through it. It may or may not make any difference, but it sure is fun to watch the neighbors freak when they see the massive cloud of smoke.

nope,,,

its a "knock" sensor - not a pre ignition sensor.

It prevents KNOCK,,you will still have pre ignition rattle using sub standard fuel. And you will have the ECU retarding the timing and reducing HP and Fuel Mileage.

This question has been gone over so many time in this group that it simply does not justify a reply.

The car needs Premium - you should not have bought it if you do not want to feed it.

Actually in the FSM, they call it a detonation sensor. It is actually a little microphone bolted to the top of the engine.

In any event, experience says you are wrong. Exactly what Nisson do you drive and what experience have you had that proves your assertions? The five Nissons rolling around my family for the past 10 years ('96 & '97 i30s, an '02 Pathfinder & a '91 240sx) all run just fine on 87 octane without any human audible pinging and rattling. The manufacturer provided owner's manual for each of them says the same thing: "regular gas of at least 87 octane is required. Use 91 for increased performance." I have tested each with multiple tanks of 91 and multiple tanks of 87. There is no rattle or ping detectable by a human. The mileage difference is approximately 1 MPG, and that only on the Pathfinder, and then only when cruising it at 80 MPH.

And yet you do...

That car does not need premium. You start screaming this every time anyone says they put regular in one of these cars. Never mind the fact that Nisson says it only requires regular gas, but premium for "increased performance". These cars will run just fine on 87 octane gas without thrashing themselves to death. If the OP is experiencing rattling and pinging, then something else is wrong.

'98 Maxima 5-sp,

Nissan says it requires Premium, and can run on regular, with reduced performance.

Just like any other of a dozen other high compression preformance cars I could name.

Your rattles, you just are to cheap to notice it.

Actualy,,I designed and built the knock sensors,,,

and your qualifications are?

Well, I can read and it says 87 octane under the fuel door. Can you read?

Not quite. The manual recommends 87 octane. It also says for increased performance to use 91. It says nothing at all about 'requiring' premuim. I can scan the page and upload it if you like.

Mine doesn't on 87. Mind you, the altitude could have something to do with that. It DOES perform better on premium though and that is what it usually gets. If you can buy the car, you can afford good gas.

You must have different manuals than the rest of us. Nissan says it requires 87 and can make use of 91.

BS

No it does not,,,,my 2000 Maxima :

It says "Premium Fuel Recommended for Maximum Performance".

Its right on the fuel door in 50 point type.

In the owners manual it defines Premium Fuel as min 91 octane.

Apparently you are the one with the reading problem.

I have the manual right in front of me - it recommends 91, and says it can run with reduced performance on as low as 87.

On 87 its going to retard the hell out of the timing (within the range allowed by the ECU), and its going to "rattling sound" under heavy acceleration.

And yes,,if you live in Denver, in a cool climate, that reduces the octane requirement across the board - 87 becomes 91. You probably can buy 84 in Denver.

The original poster admits to using 87 octane, and is complaining to his mechanic about a "Rattling noise". So in order to save 5 percent on fuel costs, he is going to have the mechanic do what?

This fuel issue has been thrashed over so many times it hardly is worth the time to type yet another reply. Go to maxima.org and see what kind of fuel they say you need.

And I agree 100 percent, if you can afford this car, you can afford to forego one Star bucks Latte a month for the right fuel.

It says it will run with reduced performance on 87.

No, I don't have a 2000 Maxima.

Mine says it recommends 87. It also recommends 91 for best performance.

Nope. Not for me. I drive my car quite hard. I like how it sounds when it pulls hard.

Don't live in Denver but we are about 2800ft here. I have used 87 but I usually use 91 as it does make a difference in performance.

I am not arguing that point. I am saying you are wrong in your information to him. Another poster has told you the same thing as I did.

No need. Been there, done that. I don't need anyone to tell me what I need. I am telling you what worked for me. Pardon the pun but your mileage may vary. End of story.

No disagreement there.

Doesn't say anything about pinging though. That is far worse than reduced performance.

so why are you posting on a Maxima group - regarding a 2000 Maxima?