Spark Knock

[dankapp]

I have a 01 GMC 1500HD. I have been noticing a bad spark knock when accelerating hard. I tried to switch to a higher octane fuel but didnt notice any improvement. Is there anything that I can look for or just take it to the dealer? Not sure if they are related or not but it has been hard to start latley also. It takes quite a few cranks to get it to start. Thanks for any help.

[Zembonez]

I have a 01 GMC 1500HD. I have been noticing a bad spark knock when accelerating hard. I tried to switch to a higher octane fuel but didnt notice any improvement. Is there anything that I can look for or just take it to the dealer? Not sure if they are related or not but it has been hard to start latley also. It takes quite a few cranks to get it to start. Thanks for any help.

Sounds like carbon buildup to me. I know a lot of guys in here have used something called Seafoam. You might try doing a search on seafoam.

 

Maybe somebody will chime in that has used it. Some of the posts I've read claimed great results.

 

I see you are rather new here. If we haven't already done so... WELCOME TO THE SITE!

[Zembonez]

Here is a quote from one of the threads talking about seafoam and how to get rid of spark knock.

 

 

Well, my pinging was getting worse by the day but, today I used Sea Foam and now it's like it never even had a problem. The only way to add it is through a vacuum line while the engine is running (I chose the brake booster line; somebody needs to be inside with their foot on the throttle to keep the engine from stalling) which will cause the MIL (malfunction indicator lamp) to turn on. Luckily, I had access to an OBD II scanner to turn it off with because shops can charge a lot to simply check for codes.

Sea Foam should be available at your local auto zone.

[minibike132]

I have a 01 GMC 1500HD. I have been noticing a bad spark knock when accelerating hard. I tried to switch to a higher octane fuel but didnt notice any improvement. Is there anything that I can look for or just take it to the dealer? Not sure if they are related or not but it has been hard to start latley also. It takes quite a few cranks to get it to start. Thanks for any help.

Sounds like carbon buildup to me. I know a lot of guys in here have used something called Seafoam. You might try doing a search on seafoam.

 

Maybe somebody will chime in that has used it. Some of the posts I've read claimed great results.

 

I see you are rather new here. If we haven't already done so... WELCOME TO THE SITE!

 

 

 

 

 

+1, I do the same thing except I use a can of GM top engine cleaner. I do it with a hot engine and when the can is just about gone I let it die then let it sit off for at least a few hours. That lets the chemicals really work. Then start it up and clear it out and change the oil just in case some of the cleaner made it's way past the rings. Welcome to the site.

[dankapp]

Thanks. I had thought about trying the Seafoam. I will give it a shot this weekend and see if it helps any. Thanks for the input.

[C6Racer]

It turned out that the reason for the MIL was because cylinder #2 was misfiring. I guess I poured in the Sea Foam just a tiny bit too fast so it fouled out the spark plug. I popped in a new plug and the engine purred like a cute fuzzy kitty. haha The pinging never did come back. Thanks Sea Foam! In case you're wondering I'm the guy Zembonez quoted.