engine knock when I press gas

[hitwriter]

Hi,
I have a 1997 camry. The engine knocks when I press the gas. When I first start the engine, it idles fine- makes no noise what so ever. The sound is not a hard knock, but I do believe it is in the block. Is there a way to check this Before I change the whole motor .

[Gun5]

bring it to a mechanic if your asking these kind of questions you need to....

[Stillrunning]

Are you sure it's not a ping, as in pre-detonation.

[Plaz]

Originally Posted by hitwriter

Hi,
I have a 1997 camry. The engine knocks when I press the gas. When I first start the engine, it idles fine- makes no noise what so ever. The sound is not a hard knock, but I do believe it is in the block. Is there a way to check this Before I change the whole motor .

You might have a look at my post here about a similar problem ....
2000 Camry tick tap ping only when warm

Mine is not 100% solved yet, but the problem improves greatly if I use high octane gas. It also improved a bit after I sea foamed the engine. That tells me it's not mechanical. Why would a mechanical problem disappear when I use 93 octane and return when I use 87? I was thinking about replacing the knock sensor next since that's what controls timing on my generation engine. Your year is a bit different than my 2000. Good Luck.

Plaz

[Plaz]

Originally Posted by Plaz

I was thinking about replacing the knock sensor next since that's what controls timing on my generation engine.

I replaced the knock sensor this week without any improvement. Not suprizing since there was no sensor error coded, but I decided to try it.

I've done some more research and I'm wondering if my ping could be related to my timing belt change that was done around the same time as the ping first appeared. It was done by the dealer and you normally assume if the car is running ok, that they've done the job right. But I've read other threads for differnt type cars that developed a ping when a new belt was installed just one notch or tooth off. If I find out, I'll post the results.

Plaz

[Jimnist]

The mechanic could have over-advanced the ignition timing.

Pinging, pre-detonation or 'engine knock' usually only occurs during load, so it is most probably pre-detonation. A quick fix would be to run higher octane fuel.

Edit: Okay, just read your 2 previous posts and yes, definitely a case of pinging. Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause detonation.That's why you use it in high performance' engines to prevent detonation(engine knocking or pinging) due to the high compression ratios.

Here's a helpful link: http://www.aa1car.com/library/spark_knock.htm

[Plaz]

Originally Posted by Jimnist

The mechanic could have over-advanced the ignition timing.

Would they have done that by way of the belt placement, or is there another way to adjust timing on my 2000 5S-FE engine?

I'm definitely aware that excessive ping is a bad thing and that's why I'm on a hunt to solve it. The higher octane helps, but I'm after the complete cure.

Plaz

[ONE_to_HATE]

my car sounds like a freakin' diesel and i can care less- can't wait for that 5s( a down right blasphemy of an engine.. imo) to dieeee!!

[Jimnist]

Originally Posted by Plaz

Would they have done that by way of the belt placement, or is there another way to adjust timing on my 2000 5S-FE engine? Plaz

To check timing, you should use a timing light. Put 'white-out' dots on the crank pulley and check the light turn on when it passes the correct point. I'm not sure what it should exactly be set for gen 3/4's are, but my Gen 2 is 10*BTDC. You also have to jump terminals in the diagnosis connector to stop the ignition system from advancing or retarding the timing.

If it's not correct you'll have to open the distributor and adjust the spark timing.