Knock Knock, Thoughts?

Engine seems to knock or ping when I first start it up after about a minute or so from first driving it it goes away. The sound reminds me of a muffled machine gun shooting a tree or like whacking a peice of wood repeatedly. But like I said, it goes away within a minute of driving it.

I am also due to have my spark plugs changed…could that affect it?



Thanks and peace out.

It might be helpful to know what kind of car we’re talking about. Year, make, and model, and engine type, please.

Are you using the recommended fuel octane rating for that engine?

Yeah, Sorry about that, tis a 99 Ford Escort 4cyl 2.0 engine. Seems like everytime I start it, it knocks but like I said, within 2 minutes at my next spot to idle, the sound is gone. It’s more noticible when I leave work or start the car in the AM.
I have tried using Higher Octane, but that doesn’t help much. Also, according to the manual it said higher octane can actually be the cause of ping because the engine gets used to it. Is that true? Right now I am using Reg. Unleaded. Thanks, and peace out.

Have you checked the oil?

Seems so simple, but it sounds to me like your oil is draining down when the car sits for awhile. Once you run it for two minutes the pressure has built and it is getting to the top end. I think in the very least checking oil and maybe an oil change are in order. Is this a high mileage vehicle?

Higher octane is for higher compression ratio engines, and though I have never looked at the ratio on an excort, my strong guess is you should burn regular.

A spark plug change never hurts, and is relatively inexpensive. Worth doing. When you pull them, check what kind of wear they are experiening as you may need wires.

Besides octane-related ping, poor lubrication, and the need for new spark plugs, I have another possibility.

Could this possibly be piston slap that the OP is hearing? Since the noise seems to go away within a short period of time, and since that is characterstic of piston slap, I think that this is another item to add to the list of possible causes. Luckily, this is not something that someone usually has to remedy, as it is fairly benign in most cases.

While the OP’s description of the noise is not the way that I would describe piston slap, I have found that descriptions of noises is very individual, and thus it can be very difficult to identify a noise based on someone else’s description of it.

Added part: I have checked the oil regularly, it is not losing it, nor burning it. Is this like a carbon related issue? Also, the sound does not increase speed with the speed of the rpm’s

“Also, the sound does not increase speed with the speed of the rpm’s”

Well, then that rules out ALL of our guesses!

Anyone care to give this another shot? I am stumped by this one.