****.
Lately I have been getting a valve noise when under medium to hard acceleration. This noise sounds I'm running v-e-r-y low octaine gas.
It's similar to a low octaine knock but is more like a rattle.
Definatly sounds like the valves, but I could be wrong.
This just started this week. I have a 99 SE, 5-speed and a PR CAI.
I run Sunoco 94 octaine fuel, Mobile 1 syn oil. WTF? this is blowing my mind. Anyone ever hear of this issue? 51K miles on the car.
BTY, can the cold winter air be doing this? I don't think so.


Any comments are welcome, I'm about ready to take it to the dealer.

Thanks in advance

 

Is it possible that an exhaust component is rattling, or something like your heat shield is rattling against your exhaust? Happened to me with my first Maxima...
Chad

 

Yeah, MaximaChad sounds right. Check your heatshield under your catalytic converter....and then go from there.

If it's a clicking noise, this might sound dumb but, are you very low on oil?

 

Just checked the oil, it's ok.
Damn, I don't see how the sound could be coming from the exhaust
system, it very much sounds like valves, when the exgine is under a fair amount of load. How the heck would I check to see
if it's an exhaust system noise?

 

My suggestion would be to get a friend, have him/her look under the car when you rev it in P or N, and they could try to pinpoint if it is actually coming from udner you.

If not, pop the hood and gently rev it again to see if they can locate another area where the niose is coming from.

Unless someone else diagnosis your problem on this forum sooner...

 

What your saying makes sense. The problem is that the valves
don't rattle or "ping" unless the engine is under a fair amount
of load, simply reving the engine in neutral (5-speed) will not
manifest the problem.

 

Try a different brand of gasoline or buy a bottle of octane booster.

 

I use Sunoch 94 octaine, maybe it's a bad tank of fuel.

 

Hate to beat this to death, but is there any other comments?

 

My car will occasionally knock under hard acceleration. IT usually seems to be when I'm comming out of a turn. I would try a injector/valve cleaner in w/ my next tank of gas. You may also want to check your ecu - it's possible for the knock sensor to go bad, and since it doesn't trip the CEL it goes undetected. Is your oil changed frequently? blah, blah, blah, Try the cleaner first and give it a tankful to work, if you still have the problem try the knock sensor or post again. GOod luck.

 

Thanks, I'll give the injector cleaner a try on the next tank of fuel. That would be a cheap solution. ::crosses fingers::

 

mine used to rattle and it was the timing chain I just pulled the motor and it was very loose I dont know why but Ive heard of quite a few people have T Chain noise. Mine mostly makes the rattling noise when its cold. I would listen under the hood and see if you can tell where its coming from.

 

yeah mine has the same noise pattern, especially when cold. I think its the timing chain tensioner or rod bearings are worn out.

 

I hate that timing chain noiseI hope my new motor clears things up.

 

Damn, I hope this is not the problem, I only have 52K miles on the car. Anyone know of the engine/components are covered under the 60K warrenty?
I'm about ready to take it to the dealer, to find out what the hell is going on.

 

I did notice something the other day.
Under the TB is "something" which 4 vacuum lines
plug into. one of the vacuum lines is missing. there
used to be a line there before because the metal is clean
and shiny where the rubber tube used to plug into, could
this be a timing advance or something to that effect?
If so, I could understand some valve noise, I'm fishing
here can anyone please HELP?????

 

Hey saw this in another thread:

"Guys, this is not a good idea. The coolant line that runs into the throttle body is used to cool the EGR gasses and to help control idle. My friend did this to his 97 max and his throttle plate started sticking and his idle was irregular. The little space on the TB that recieves coolant doesn't have a large enough suface area to heat up the incoming air anyway. If the EGR passage doesn't recieve proper cooling the engine may detonate and actually loose power. And I think that 6hp gain is BS. Just my .02."

I DID clean my TB right about the time the valves started knocking, could I have done something to F things up with the TB???????I used Vavoline TB cleaner, then ran a tank of injectoc cleaner, still knochs under moderate acceleration. WTF?

 

This is a tough one. So you just cleaned your TB recently, now you see a vacuume line off. Search for that line first. I don't think your hearing valve rattle, that doesn't come on that fast, espeically if you take care of your motor. I'm thinking your engine is definately pinging. Bad gas could be at fault here. Chew up 1/2 your tank and put some different gas in there. It should clear up or at least get better. You don't want to drive around with a bad ping for to long. Octain bost or/and a bottle of Techron can't hurt either.

 

Thanks, but I have been through 3 tanks of gas, one with injector cleaner. I run 94 octaine (Sunoco) fuel. I would bet my left nut that this is valve noise. (Hope I'm wrong).
It sounds like the old days when unleaded fuel first came out and a lot of cars would rattle or ping. It's driving me f-ing crazy.
This weekend I am going to take off the TB to see if I can find the "missing" vacuum line. Failing that, it's to the dealer

 

Good luck man, the vacuume line might fix you up. Let us know what you find. Hope you don't have to take it to the dealer.

 

I have the same noise. Did you figure it out yet?? If so, please reply. Thanks.

 

bump

 

whats the latest?

 

Yes I have the same problem. Valve noise under moderate accleration.
Injectors ar clean and gas Octane is fine.

 

ok thats the noise of your car miss firing, I hate that noise, and it feels like theres no power right.