My engine knocks sometimes when the car is on and just sitting there and i rev it alot, It seems to be comming from only one cylinder or that area around there.
What could this be???????

 

Either bad gas or you revving your engine a lot....try gas from a different station or add some octane booster occasionally.

- -

 

Isn't octane booster bad for your spark plugs?? I've heard that they leave a residue on the plug, which can cause them not to perform as well. Correct me if I'm wrong. Thanks.

 

no its not bad. It has additives which control the burn/fire that ignites when the spark plug sparks...without such additives the combustion is uncontrolled and thus you have knocking. So up the octane a little bit and stop reving the unloaded engine - its not good for it.

 

Thanks guy, I usually put Mobil 93 octane, I will switch, I thought mobil was the best but i will try some others, Thanks.....

 

I wonder why the knock sensor didn't help out. Was the fuel that poor?

 

Maybe i have to change my knock sensor, I'm not sure.....

 

It makes sense to try the fuel change first. But it should be OK with 89 octane. If after the 93, you test out 89 and it still knocks, I'd see if there are any codes on the ECU.

 

The "knock Sensor" in our cars actually detects PING. Ping or knock as it's called is caused by the air/fuel mixture igniting to soon and pushing down on the piston before it reaches top dead center. This usually happends when the engine is under load, not when it's free reving.

If your hearing a knocking from your motor while it's free reving then chances are you have a spun bearing, excessive rod bearing wear or a very lose timing chain. This is not good. I would get an oil analysis out to Blackstone Labs ASAP. If indeed you have bearing problems, they'll see it in the oil.

If the timing chain is extremely lose, it may be slapping against the cover. This noise is usually pronounced at start up.

 

im not sure if ive experienced it before- what exactly does a ping or knock feel / sound like?

 

Ping sounds like lose metalic marbles in your engine. Happens under load.

Knock - take a ball pean hammer, cover the end with some cloth and bang it against your engine block. Or just knock on a wooden door.


Knock Knock........

Who's there ???

Your motor......

My motor ??????


Yes, it's time to rebuild me!

 

oh, i guess i havent had the problem yet. sounds pretty bad.
how long does the noise usually last when it occurs? is it momentarily. so it happens when the octane levels arent suitable?

 

CHECK YOUR SPARK PLUGS!

The same thing happened to me except the car would die after a few minutes. Turned out I just had a damaged spark plug.
-Cyrus

 

Ping is momentary and the KS will detect this and retard timing to make it stop. You should never hear ping in the VQ motor.
(unless your KS is gone bad)

Vyrus has an excellent point. Check your spark plugs. If one is misfiring, it could cause piston slap which may be heard as a knock!

 

I just checked my spark plug and it's the Stock plug and it's black and all burned up, I checked the one for the cylinder that i hear it from and what the hell is a rod bearing, How much and how do i change that?

Also is it the spark plug, I have 88,000 miles on my car.

 

So change your plugs! Your car has NGK Platinums that should have been replaced at your 60,000-mile service. If it's black that means they definitely need ot be replaced, probably the root of your problem.
-Cyrus

 

Rod bearing: is the bearing that fits inside the connecting rod.
The connecting rod attaches, at one end, to the crankshaft. At the other end it attaches to the piston. (Major engine component)
IF you don't know what it is... YOU don't want to replace it. Pay someone to do it if you have a bad one. If you want to tell for sure if it is a rod knock (from a bad rod bearing) just listen to your engine when you decelerate in gear. (get up to about 45 and let off the gas). If it knocks when you let off the gas... you can be 98% sure you have a rod knock. If not... it's something else.

88k miles on your car? That's about the time when O2 sensors start failing and you need to clean out your throttle body and stuff, too.
Dude, read the FAQ's on this site. They will step you through what you need to do to make sure your Max is running to the MAX!