Read My Plugs Please
Thread Starter
Melting Slicks
Joined: Nov 2010
Posts: 2,626
Likes: 195
From: On the east coast we drive until we die
The top pics are after 40k miles and the gap opened up to about .065. The bottom pics (new plugs) are gapped at about .048. It's just the camera angle.
Race Director
Joined: May 2004
Posts: 16,667
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From: Raleigh, NC
St. Jude Donor '15
Racer
Joined: Jan 2015
Posts: 378
Likes: 34
From: Clarksville TN
if your going to take it to a shop or have access to a gm tech2 take a look at your coils. recently had issues on my silverado with the 5.3l. wasnt throwing codes but i had a coil going bad in it(which could cause a rich condition in that cylinder). it occasionally had a ruff idle and got worse over time. you didnt mention the year of the car. but i recently replaced the the coils in my 05 (for looks only) and the old ones were the same p.n. as the ones in the 07 silverado. so it didnt cost me anything to get it fixed, since i never throw out good parts. it is just a suggestion to go with.
Burning Brakes
Joined: Nov 2010
Posts: 1,008
Likes: 12
From: The only state to ever kick another country's ass! TEXAS
Absolutely. What's throwing everything off is the noise which admittedly could be unrelated, but might not be. That's why I recommended the compression and leakdown tests first. They are probably the easiest things to do, and will eliminate some possibilities. Swapping injectors would be a good second step since the plugs and wires have already been replaced.
Thread Starter
Melting Slicks
Joined: Nov 2010
Posts: 2,626
Likes: 195
From: On the east coast we drive until we die
It's an '07
Thanks for all of the suggestions. I'll mention them to my shop.
The best way I can describe the noise is like a crackling or sharp static type sound. Would a bad coil make a sound? Why wouldn't I get misfires?
Thanks for all of the suggestions. I'll mention them to my shop.
The best way I can describe the noise is like a crackling or sharp static type sound. Would a bad coil make a sound? Why wouldn't I get misfires?
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Race Director
Joined: May 2004
Posts: 16,667
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From: Raleigh, NC
St. Jude Donor '15
I'm honestly not sure. I've seen it done before when a tuner couldn't figure out what was actually wrong. It was easier to just disable the codes than to figure out why it was misfiring.
I **think** it's more common on larger cam'd cars.
Not saying that's necessarily what's been done to yours. just throwing out information hoping something helps
I **think** it's more common on larger cam'd cars.
Not saying that's necessarily what's been done to yours. just throwing out information hoping something helps
Thread Starter
Melting Slicks
Joined: Nov 2010
Posts: 2,626
Likes: 195
From: On the east coast we drive until we die
I'm honestly not sure. I've seen it done before when a tuner couldn't figure out what was actually wrong. It was easier to just disable the codes than to figure out why it was misfiring.
I **think** it's more common on larger cam'd cars.
Not saying that's necessarily what's been done to yours. just throwing out information hoping something helps
I **think** it's more common on larger cam'd cars.
Not saying that's necessarily what's been done to yours. just throwing out information hoping something helps
Thread Starter
Melting Slicks
Joined: Nov 2010
Posts: 2,626
Likes: 195
From: On the east coast we drive until we die
*UPDATE*
I finally got a chance to drop the car off at my tuner. The leak-down test was perfect but a compression test showed a little high on cyclinder 3. None of the springs are broken. My tuner seems to think it's a spun lifter so the heads are coming off next and we'll see what the extent of the damage is and go from there.
Any ideas how bad things could be? What have you guys seen in regards to damage in these situations? Think it started eating the cam?
I finally got a chance to drop the car off at my tuner. The leak-down test was perfect but a compression test showed a little high on cyclinder 3. None of the springs are broken. My tuner seems to think it's a spun lifter so the heads are coming off next and we'll see what the extent of the damage is and go from there.
Any ideas how bad things could be? What have you guys seen in regards to damage in these situations? Think it started eating the cam?
Last edited by 5knives; Sep 10, 2015 at 07:13 PM.
Melting Slicks
Joined: Dec 2013
Posts: 2,232
Likes: 315
From: Bridgewater New Jersey
*UPDATE*
I finally got a chance to drop the car off at my tuner. The leak-down test was perfect but a compression test showed a little high on cyclinder 3. None of the springs are broken. My tuner seems to think it's a spun lifter so the heads are coming off next and we'll see what the extent of the damage is and go from there.
Any ideas how bad things could be? What have you guys seen in regards to damage in these situations? Think it started eating the cam?
I finally got a chance to drop the car off at my tuner. The leak-down test was perfect but a compression test showed a little high on cyclinder 3. None of the springs are broken. My tuner seems to think it's a spun lifter so the heads are coming off next and we'll see what the extent of the damage is and go from there.
Any ideas how bad things could be? What have you guys seen in regards to damage in these situations? Think it started eating the cam?
FYI, engine would be very hard to keep running with a broken valve spring.
Keep us updated.
GL
Melting Slicks
Joined: Dec 2013
Posts: 2,232
Likes: 315
From: Bridgewater New Jersey
If you are referring to my post, yes you can see that the valve is actuating, but it would be hard to evaluate how much lift and the duration by just eyeballing it.
My thinking is that if the lob and/or the roller is damaged, that the limited duration and lift will influence the exhaust scavenging from the combustion camber, hence the black sooty spark plug.
This may also support the theory of higher compression of just the #3 cylinder.
My thinking is that if the lob and/or the roller is damaged, that the limited duration and lift will influence the exhaust scavenging from the combustion camber, hence the black sooty spark plug.
This may also support the theory of higher compression of just the #3 cylinder.
Last edited by extrapilot; Sep 12, 2015 at 12:29 PM.
Thread Starter
Melting Slicks
Joined: Nov 2010
Posts: 2,626
Likes: 195
From: On the east coast we drive until we die
**UPDATE**
I just got off the phone with my tuner. It looks like the roller on the lifter started eating away at the cam lobe. He believes it was from a weak spring causing the lifter to slam down on the cam during a high RPM run. Supposedly my intake valve was barely opening. So now they're pulling the motor to check the bearings, crank, and cylinder walls hoping all those metal shavings didn't destroy everything. I should know by the end of the week. Isn't this a fun hobby...
I just got off the phone with my tuner. It looks like the roller on the lifter started eating away at the cam lobe. He believes it was from a weak spring causing the lifter to slam down on the cam during a high RPM run. Supposedly my intake valve was barely opening. So now they're pulling the motor to check the bearings, crank, and cylinder walls hoping all those metal shavings didn't destroy everything. I should know by the end of the week. Isn't this a fun hobby...
Melting Slicks
Joined: Dec 2013
Posts: 2,232
Likes: 315
From: Bridgewater New Jersey
**UPDATE**
I just got off the phone with my tuner. It looks like the roller on the lifter started eating away at the cam lobe. He believes it was from a weak spring causing the lifter to slam down on the cam during a high RPM run. Supposedly my intake valve was barely opening. So now they're pulling the motor to check the bearings, crank, and cylinder walls hoping all those metal shavings didn't destroy everything. I should know by the end of the week. Isn't this a fun hobby...
I just got off the phone with my tuner. It looks like the roller on the lifter started eating away at the cam lobe. He believes it was from a weak spring causing the lifter to slam down on the cam during a high RPM run. Supposedly my intake valve was barely opening. So now they're pulling the motor to check the bearings, crank, and cylinder walls hoping all those metal shavings didn't destroy everything. I should know by the end of the week. Isn't this a fun hobby...
I've seen plenty of roller cams wipe out, just like the old flat tappet types that was used in the past.
This can happen sometimes for no apparent reason.
Good luck, hopefully there is not extra damage to the engine.