Spark Knock

[gardnerk20]

Hey Guys,

Just wanted to ask about spark knock, I have a 1997 Chev. Z71 with a 5.7 liter. It spark knocks no matter what grade or brand of fuel i use, I have put cleaners in it and even taken to the dealer just to pay them $80 and all they could tell me is that it was carbon buildup on in the engine and suggested something they call a motor vac. (what ever that is) for $180. I guess what i am trying to ask is there anything i can do or check to solve this problem. Any help or suggestions would be very appreciated. And by the way it has 124,000 miles on it and runs fine otherwise.

Thanks in advance

gardnerk20

[kenny-1907]

What you are describing sounds like pre ignition caused by the carbon build up getting so hot in the combustion chamber that IT will ignite the fuel/air mixture before the piston has had a chance to compress it all the way and basically it is beating the hell outta your pistons (as the piston is compressing the fuel/air mixture, the heat of the carbon buildup ignites the mixture causing your piston to try and compress against the premature explosion that is supposed to force it back down). I would get it looked at right away even if it means having to pay the 180 cause it WILL damage your engine if you keep driving it like that.

[gardnerk20]

Originally Posted by kenny-1907

What you are describing sounds like pre ignition caused by the carbon build up getting so hot in the combustion chamber that IT will ignite the fuel/air mixture before the piston has had a chance to compress it all the way and basically it is beating the hell outta your pistons (as the piston is compressing the fuel/air mixture, the heat of the carbon buildup ignites the mixture causing your piston to try and compress against the premature explosion that is supposed to force it back down). I would get it looked at right away even if it means having to pay the 180 cause it WILL damage your engine if you keep driving it like that.

Thanks i,ll get with the dealer and get the details.

gardnerk20

[chahonda]

Originally Posted by gardnerk20

Thanks i,ll get with the dealer and get the details.

gardnerk20

you can get some cleaner that is like the same stuff that the dealers use. its called SEAFOAM. it works very well....you warm your motor up and pour about 1/2 the can in the throttle body or brake booster vacuum hose. you will have to keep it idled up a bit to keep it from shutting off. after you have used about half of the can, shut it off and let it sit about 5-10 minutes to break up the crap in the motor. when you restart it, drive it around about 10-15 minutes and it will smoke like hell. its a good idea to replace the spark plugs after this procedure as well. wouldnt hurt to change the oil as well but its not needed. you can put the remaining half of the can in the oil or pour it in the gas tank.
i have used SEAFOAM before and it really does work great.

http://www.seafoamsales.com/

[Fireplug]

What did they not test your knock sensor. Its there to help stop any knock/ping

[gardnerk20]

Originally Posted by chahonda

you can get some cleaner that is like the same stuff that the dealers use. its called SEAFOAM. it works very well....you warm your motor up and pour about 1/2 the can in the throttle body or brake booster vacuum hose. you will have to keep it idled up a bit to keep it from shutting off. after you have used about half of the can, shut it off and let it sit about 5-10 minutes to break up the crap in the motor. when you restart it, drive it around about 10-15 minutes and it will smoke like hell. its a good idea to replace the spark plugs after this procedure as well. wouldnt hurt to change the oil as well but its not needed. you can put the remaining half of the can in the oil or pour it in the gas tank.
i have used SEAFOAM before and it really does work great.

http://www.seafoamsales.com/

I have used seafoam twice and it helped but did not cure the problem, but i was checking things out today and i think that someone else and pulled the distributor for whatever reason and did not put it back in correctley. what i did was brought the engine up on TDC and reset the dist. correctly ( i think ) and now it seems to be doing fine. what i think happened is when they put it back in they had it one tooth advanced and that would not allow the computer to correct the timing (i think) anyway so far so good. thanks for the advice i will let everyone know if really solved it or not.

gardnerk20

[gardnerk20]

Originally Posted by Fireplug

What did they not test your knock sensor. Its there to help stop any knock/ping

yes they did, well they where supposed to.

thanks gardnerk20