new plugs/knocking

[stephsguy99ga]

i replaced the spark plugs the other day and now i notice a knocking sound comming from the engine. the noise was not there with the original plugs, i used acdelco plugs. the car idles fine when its in park and at stop lights and i have no service engine lights on. does anyone know what is causing this knocking sound, im pretty sure it has something to do with the spark plugs sence the noise was not there before i changed them. i dident replace the rubber boots could that be the problem?? any info would be helpful

[stephsguy99ga]

anyone?????

[Bjornboy81]

I'm not sure what it could be. But please give us a little more time than a half hour before reposting "anyone?????"...we're not that good ;)

I don't think not replacing the boot will do that....what kind of noise is it (detonation knock or something hitting) and did you tighten the plugs to a specified torque? :)

[Matt95GT]

Which AC Delco plugs? Did you gap them properly?

Any signs of misfiring? Or is running smooth despite the noise?

[rixGAphx]

Generally, there is NOTHING related to changing plugs that will result in a traditional 'knocking' or 'pinging'. Knock and ping are the specific noises from 'predetonation', and changing plugs won't affect that (assuming you used the right model of plug and gapped them properly).

So, we need a little more info:
* * *

Yes, please describe the noise.

Where does it seem to come from (engine right, engine middle, high or low, etc.)?

Does the rate of sound increase/decrease with rpms?

Is the noise only present at idle, or also at road speeds?

If you climb a steep grade in low ger, like a driveway or parking garage ramp, does the 'knocking' get REALLY strong?
* * *

Did you have other noises/misfires BEFORE the plug change?
(I'm thinking this hoise might have been there all along, but was previously masked by a noisy-running engine.)
* * *
When you changed the plugs, did you do any other service, like change air filter, or oil, or clean some stuff?

Mebbe a tool or something else is setting loose under the hood, and making a mechanical 'tap-tap-tap' noise.

Standing by.
-Rick

[stephsguy99ga]

its kinda hard to describe it sounds like its comming from where the spark plugs are. its more a "tick tick" then a pinging sound, yes i can hear it when ideling, when i take off it seems like the noise gets faster and faster, its not loud, i cant hear it in less i stick my head out the window. the guy at murrys said that they were pre gaped to .60 or close to that. they are ac delco platinums. i dident do anything else to it, but the plugs. it seems to be ideling fine , i cant even feel the engine running when sitting at a light. when u say specified torque how do i know how hard that is? i just tightened them to i couldent turn them any more with a socket. i dont think i left anything under the hood ill go look... the only other thing i can think of is the last 3 fill ups i been using 93 octain could that be it.??

[Matt95GT]

Originally posted by stephsguy99ga
the guy at murrys said that they were pre gaped to .60 or close to that.

That's one of the worst assumptions to make. Always gap the plugs.

It's also very important to torque the plugs to spec.

[stephsguy99ga]

how do i gap the plugs... (sorry im kinda new at this.) torque the plugs to spec. how do i know how tight to do it?

[Matt95GT]

Use a plug gapper. Any auto store should have them. One like this is cheap and easy to use...
http://www.nationalwholesaletools.com/ProductImages/full/1873.jpg

You'll need a torque wrench to tighten the plugs to spec.

[rixGAphx]

You've got a 2.3 DOHC engine, and there's a 'tick, tick' from the area of the plugs.
On each side of the plugs is a camshaft with lots of things going tap-tap/tick-tick.

Your 'ticking' sounds like basic valve chatter to me.
Though I've never driven a 2.3 nor worked on one, and
I don't know what the 2.3's valve acuation is (mechanical, hydraulic, rocker arms???), I DO know the valvetrain is capable of some significant noise.

Sometimes the ticking is from normal wear, sometimes from extraordinary wear, sometimes from lousy oil pressure, and sometimes from a broken component.
On hydraulic valve trains, the lifters may get clogged and stick, or one may have failed. Instant ticking, guaranteed.

Get an oil and filter change; should get one every 3000-5000 miles anyway.
This often helps reduce or eliminate valvetrain chatter.
* * *
Plugs from the factory are nowadays 'pre-gapped' like the fellow said. However, the engine that the plug goes into might require a different gap.
For example, the EXACT plug for the '96 3.1 V6 (mine) are suitable for the '02 3.4 V-6.
However, mine need a gap of 0.050 inch ("fifty-thousandths") and *some* 3.4's require 0.060" IIRC.

So, the 'factory gap' might not be suitable for YOUR engine.
Further, plugs can be banged around a bit during shipping; this *might* knock the electrode closer to the tip, thereby reducing the gap from the preset 0.050 to something like 0.035.
Finally, the factory equipment might have been out-of-tolerance the day your plugs were 'pre-gapped', and EVERY plug is wrongly gapped.

Therefore, always gap the plugs as you install them.
* * *

Your engine doesn't need 93 octane, and so it's a waste of money, but it won't hurt anything other than your wallet.
Since your engine is designed to run on 87 octane IIRC, using higher-octane gets you absolutely ZERO additional power, ZERO milage increase, and ZERO engine longevity.
Changing from the previous 87 or 89 octane would NOT result in 'ticking' noise.

IF you had a high-performance engine DESIGNED for 92 octane, then changed 'down' to 87 octane, you almost definitely would get 'knocking' from the lower-octane gas.
That's the basic definition of 'octane': The point at which gasoline knocks.
* * *

Regarding the ticking:

Since you don't know how to gap or torque plugs, then you're at a very novice state as a mechanic.
That's not a bad thing, but it means any further diagnosis will require tools, equipment, and experience you just don't have yet.

I don't think there's anything more we can tell you about the ticking, other than to say, "It might be normal or it might be a major problem. Go see a reputable mechanic."

Good luck.
-Rick

[Matt95GT]

A 2.3/2.4 valvetrain should not make any noise normally. (not including worn timing chain or bad water pump... but that's makes the noise to the side) Most time that noise on a 2.3/2.4 means imminent bad news.

It seems to me that this noise occuring when the plugs were changed just seems too much of a coincidence to be unrelated.

Originally posted by rixGAphx

I don't know what the 2.3's valve acuation is (mechanical, hydraulic, rocker arms???), I DO know the valvetrain is capable of some significant noise.


Hydraulic lifters acting directly off the cams.
As I said, shouldn't be any top-end noise unless something is mechanically sick.

[stephsguy99ga]

thanx for the info i guess im going to take it to a mechanic and see what he says... ill keep u guys posted!!

[dandragonrage]

Rick, our engines are supposed to be gapped at .060, not .050

[rixGAphx]

Originally posted by dandragonrage
Rick, our engines are supposed to be gapped at .060, not .050
DOH!!

[Colin]

Check to make sure the wires are pushed properly onto the sparkplugs , that sound may be the spark jumping to the terminal inside the boot . ;)

[stephsguy99ga]

well i found out what the problem was , i had some free time today so i decided to take another look at it, one of the smark plugs was only hand tight so i put it back together and it hasent made that sound anymore. I must of forgot to tighten that one with the socket. thanks for all the help!

[Matt95GT]

Originally posted by stephsguy99ga
well i found out what the problem was , i had some free time today so i decided to take another look at it, one of the smark plugs was only hand tight so i put it back together and it hasent made that sound anymore. I must of forgot to tighten that one with the socket. thanks for all the help!

Good hear you found the issue. I would seriously invest in a torque wrench... the 2.3/2.4 head is known for "becoming one" with the spark plugs if they are too too tight.

Besides plugs, they are useful on other maintenance too... lug nuts, caliper bolts when changing brake pads, etc.

[LargeFish]

Hopefully he used anti-sieze on the threads before he tightened those plugs down...