Knocking (pinging) under acceleration
Thread Starter
Racer
Joined: Nov 2004
Posts: 494
Likes: 0
From: Charlotte NC
Pro
Joined: Jan 2006
Posts: 643
Likes: 2
From: Alexandria Northern Virginia
As a Ford tech, we used to do a top-end clean with a chemical you drew in through a vacuum port to clean carbon off the top of the pistons. It is natural to get some deposits on your engine, even using good gas. Do you have any oil coming through your PCV line or breather? If so, some of that nastyness could also add to your issue.
If you have any access to a boroscope to run down into a cylinder through the sparkplug port you could see the top of the pistons and either confirm or deny you have deposits. I know there are a number of good ways to clean it.....sucking a quart of water into your intake is NOT a good way (saw a Cobra get hydrolocked that way
).
HTH, I would not take my tune off, you know that is not the issue. If you have had no problems for years with it, that is not what changed. Find your weak link (dirty gas, low octane, carbon deposits, etc) and you have your fix!
Cassidy
If you have any access to a boroscope to run down into a cylinder through the sparkplug port you could see the top of the pistons and either confirm or deny you have deposits. I know there are a number of good ways to clean it.....sucking a quart of water into your intake is NOT a good way (saw a Cobra get hydrolocked that way
).HTH, I would not take my tune off, you know that is not the issue. If you have had no problems for years with it, that is not what changed. Find your weak link (dirty gas, low octane, carbon deposits, etc) and you have your fix!
Cassidy
Tech Contributor
Joined: Dec 2006
Posts: 10,962
Likes: 29
From: Van Buren Arkansas
Wounded Warrior Escort '11
I did get mine tuned which did not help at all. I've run Seafoam into it on two occassions that also did not help. I did run the GM Top End Cleaner into it, which did help briefly, but it seems the problem is back. Its going to the dealer on Friday for the software update. A Master Mechanic on corvettemechanic.com says that these updates are needed to compensate for the newer spark plugs plus the other issues that GM has found. Included was for the right tank sending unit that has issues as well.
Thread Starter
Racer
Joined: Nov 2004
Posts: 494
Likes: 0
From: Charlotte NC
I ran Seafoam through mine as well a few times with little if any improvement.
I did get mine tuned which did not help at all. I've run Seafoam into it on two occassions that also did not help. I did run the GM Top End Cleaner into it, which did help briefly, but it seems the problem is back. Its going to the dealer on Friday for the software update. A Master Mechanic on corvettemechanic.com says that these updates are needed to compensate for the newer spark plugs plus the other issues that GM has found. Included was for the right tank sending unit that has issues as well.
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
As a Ford tech, we used to do a top-end clean with a chemical you drew in through a vacuum port to clean carbon off the top of the pistons. It is natural to get some deposits on your engine, even using good gas. Do you have any oil coming through your PCV line or breather? If so, some of that nastyness could also add to your issue.
If you have any access to a boroscope to run down into a cylinder through the sparkplug port you could see the top of the pistons and either confirm or deny you have deposits. I know there are a number of good ways to clean it.....sucking a quart of water into your intake is NOT a good way (saw a Cobra get hydrolocked that way ).
HTH, I would not take my tune off, you know that is not the issue. If you have had no problems for years with it, that is not what changed. Find your weak link (dirty gas, low octane, carbon deposits, etc) and you have your fix!
Cassidy
If you have any access to a boroscope to run down into a cylinder through the sparkplug port you could see the top of the pistons and either confirm or deny you have deposits. I know there are a number of good ways to clean it.....sucking a quart of water into your intake is NOT a good way (saw a Cobra get hydrolocked that way
).HTH, I would not take my tune off, you know that is not the issue. If you have had no problems for years with it, that is not what changed. Find your weak link (dirty gas, low octane, carbon deposits, etc) and you have your fix!
Cassidy
j/k
Racer
Joined: Jan 2007
Posts: 482
Likes: 0
From: St Augustine FL
Make sure that its UNLEADED too unless you like replacing O2 sensors.
Apparently your tune right on the edge for 93 octane. Detonation is bad, but it takes quite a bit to destroy an NA motor. If you were FI I would be really worried. Somebody correct me if Im wrong.
Apparently your tune right on the edge for 93 octane. Detonation is bad, but it takes quite a bit to destroy an NA motor. If you were FI I would be really worried. Somebody correct me if Im wrong.
Thread Starter
Racer
Joined: Nov 2004
Posts: 494
Likes: 0
From: Charlotte NC
It's unleaded 100 I would be putting in.
I know detonation is bad. That's why I'm on CF trying to get help :-)
I know detonation is bad. That's why I'm on CF trying to get help :-)
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Racer
Joined: Jan 2007
Posts: 482
Likes: 0
From: St Augustine FL
Melting Slicks
Joined: Nov 2004
Posts: 3,424
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From: Las Vegas Nevada
St. Jude Donor '07-'08
Only thing that stopped it was running Torco. Thought it was bad gas also. Even mixed 100% racing fuel in and that helped. But then eventually it came back and that was when i had it retuned.
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
might as well use that higher timing advance. ZOOOOOOOOOOOM 
HOW MUCH $/GALLON WAS THE 100 ?
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
Thread Starter
Racer
Joined: Nov 2004
Posts: 494
Likes: 0
From: Charlotte NC
Le Mans Master
Joined: Aug 2003
Posts: 9,298
Likes: 4
From: American Canyon Lethal Injection
Also get a can of MAF cleaner and clean the MAF. He mentioned installing a intake, check it for leaks. A tune may be needed after the intake install...Good luck
Le Mans Master
Joined: Dec 2006
Posts: 7,251
Likes: 16
From: Phoenix Arizona
