Sounds like it could be bad gas.

 

Valves don't clatter when you don't use premium. That "valve train noise" is detonation making holes in your pistons, and trying to blow out your head gaskets. Sounds like your not getting the octane your paying for.

Respect
JET

 

Hey Dave,

Let me know if you come up with a solution. I have a '97 Avalon that has done it continually since around '99. The dealer looked at it several times with no solution.

I've tried every brand of gas and even ran it on premium for about 6 months. Mine only does it at certain speeds and engine load. My solution was to give it more gas and it gets past the "rattling stage".

Dave

 

Sounds like there could potentially be a problem if it's occuring regular. Detonation is basically what destroys engines, and it can do it very rapidly given the cirumstances. If you're not sure, I'd get a data logger to connect to your factory knock sensor, or better yet get an Electromotive Knock Link knock monitor (with a Bosch sensor)

Cheers,

Gary
Gruppe-S

 

dont use shell
try 76, or Chevron...

I had issues with Shell before.

 

yeah my maxima does it but i told the dealer and he was like no nothing will happen to your engine. so i have'nt bothered to do anything

 

This is interesting.

From what i've seen, the ECU should retard or advance the ignition timing through detecting EGT changes. I believe it adjusts the timing via the knock threshold map.

For your ECU to not do this, is a little curious.

Hopefully it will go away with no adverse problems later on, Dave.

 

yeha but my murano with 20 miles did it too, so i am not woried about it that much.

 

Sounds like detonation, likely due to poor gas or something. I recall some stock 350z's knock a little bit under heavy load, and low RPM and higher gears. Is that the situation when you encounter the knock?

The stock knock sensor will only retard timing when the knock is perceived as loud enough to cause engine damage. This is how factory ECU's are programmed.

To avoid this, try downshifting and keep the car in a more favorable power band and gear.

 

I always assumed most of the clattering I heard was from the normally noisy Z tranny. Though recently I walked by my hood with the engine running idle and it didn't sound to healthy.
Think maybe my granny driving coasting in sixth at 45-50 mph has caused damaging knock? My can kinda sounds like a truck on occasion.

 

I would definetly get some Chevron Techron concentrate ASAP. Carbon deposits on the pistons could be the issue driving up the compression ratio causing detonation. Audi A4's are particularly susceptible to this, and Techron always cleared it up for a few thousand miles in my A4. I now use Techron every 3000 miles in all my vehicles to keeps things clean. Don't use any other fuel aditive Techron is the only real thing.

Respect
JET

 

Bringing this VERY old thread back to life.
I have the exact same problem. A clattering noise from the engine under acceleration. I've noticed it to take place between 2000-3000 rpm. If I give it more gas it will make the noise at a faster rate before I get past that rpm range.
I've used only premium 91 gas from reputable gas stations (chevron, shell) and have had this problem for the past 3000-4000miles. I just sea foamed the car in the intake and gas tank and it seems slightly better but still very noticeably there.
Any ideas?