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Discussion Starter #1
I went to change the spark plugs on my car and the place I bought them sold me ones too short.



*Now the actual problem: I put the car back together with the old plugs back in, for some odd reason there is a loud knock when started for a couple of seconds then it stops.*

*Edit* I lost one of the coil pack bolts so is that the problem?*Edit*
 

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did the bolt fall in the head? LOL kinda a silly question but that could explain why the bolt's gone and there's noise!

the ngk looks like a plug for my engine (lsj) weird looking gap and thread on the acdelco plug. kinda confused.
 

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Discussion Starter #3
did the bolt fall in the head? LOL kinda a silly question but that could explain why the bolt's gone and there's noise!

the ngk looks like a plug for my engine (lsj) weird looking gap and thread on the acdelco plug. kinda confused.
No lost the bolt near the headlight.
 

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Discussion Starter #5
Now this sound even more stupid, but the alarm went off so I had to crank the car to shut it off, now there was no coil pack plugged in, and one spark plug missing, so did any engine damage occur? Or did it just dump fuel into the engine?
 

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what do you mean by knocking noise? knocking is supposed to mean timing knock retard, do you mean like a hollow deep knocking sound? rattling? it's hard to tell over the interwebz

^it wouldve just dumped fuel
 

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Discussion Starter #7
what do you mean by knocking noise? knocking is supposed to mean timing knock retard, do you mean like a hollow deep knocking sound? rattling? it's hard to tell over the interwebz

^it wouldve just dumped fuel
I guess more of a click, click noise?
 

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Discussion Starter #9
Is it the coil pack not making a total connection to the spark plugs so it's spark is jumping on startup and then making the noise?
 

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Discussion Starter #11
this is from removing one plug and starting the engine? did you remove all 4 plugs? did you do anything else to the car while the plugs were out? how long does the noise last?
Just removed one spark plug, didn't do anything else to the engine, the sound lasts for like one second or two.
 

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ok, try and crank it again and listen towards the front of the engine. if you're looking under the hood, it's to the left. the timing chain is housed in that part of the engine. most engine noise comes from over there. try and pinpoint where the sound is coming from.
 

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Discussion Starter #13
Do you think the Gm dealership will have the bolt for the coil pack in stock or will they have to order one?
 

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that could be why the gap looks off. to close the gap on a plug I literally tap it on a hard surface. dropping it could severely distort the gap. the gap should be .32 to .35. alldata told me .40 max and I had been doing .38 and it worked fine. .35 as of late and the car runs the same but it don't hurt to use factory specs.
 

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Discussion Starter #17
So in reference to this image, do I have to return the NGK Tr55 spark plugs for longer ones? Or would they work?

 

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I have never seen those acdelco plugs that's really weird you were using them man. I hope someone with l61 knowledge chimes in cause I am pretty stumped. maybe cause the lsj head is different? someone help! lol
 

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The LSJ Head is different. That same style plug came out of my 2.2 at 50k... Yes you will have to return them for the longer ones. And try to get the ones with the same electrode tip as what was in the car. TRUST ME, I've change my plugs only 20k miles ago and the parts store tried to sell me something like that, just not the ngk brand. I laughed then pulled the spark plug out of my shirt pocket and showed them what I needed (I like to mess with the people at these stores, they think they know more than most mechanics)...

Anyways, if you don't have the right length plug, and gap, and electrode... 1- you will do damage to your head if the plug is firing while still inside the threads of the head 2- you'll have spark knock, or it will run like crap and 3- with the amount of electricity these coil packs are putting out these days, make sure the electrode is the same material or better than stock, or you'll end up with a burnt up plug in only a few thousand miles instead of a tens of thousands...

The noise you are hearing is most likely caused by the coil you are missing the bolt on. That bolt is there for the ground on the coil, if you look where the bolt contacts the coil, there is some metal showing. Everything needs grounded out even if it is firing a spark thru a grounded sparkplug...

The knock wouldn't just go away after a sec or two if you dropped something down that little hole the plug goes in.

And your better off going to like an ace or home depot or lowes and finding the right size bolt and thread pattern, The dealer might try charging $10 for a $0.50 item...

Hope I can help.

P.S. I sure as hell hope no one on here is waiting till the 100k mark to change their plugs... Mine were pretty worn at 50k.
 

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How do you change the spark plugs?

Guys,

I also have a 2.2 L 2005 Cobalt, but I have a more basic question: How do I change the spark plugs, period? After unscrewing the oil cap and taking off the big, black plastic shroud, I see the metal engine, but it's just a smooth surface and I don't know how to open it up to get to the spark plugs. Can anyone help? Thanks.
 
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