Detonation Issues
Teching In
Joined: Jun 2009
Posts: 6
Likes: 0
I always use 91 octane without ethenol. (I can't get 93 anywhere here).
The spark plugs didn't look too bad. The first 2 or 3 threads had some
black gunk on them. The tips had white on them. They were AC Delco
plugs, so I'm assuming they were the original plugs.
I haven't touched my distributor & I don't plan to unless it breaks.
So the timing is stock.
I haven't finished the passenger side plugs & wires yet. The car seems
to be running really well now though. The passenger side plugs almost
make me miss my old integra. I could change the plugs & wires in 5 minutes!
The spark plugs didn't look too bad. The first 2 or 3 threads had some
black gunk on them. The tips had white on them. They were AC Delco
plugs, so I'm assuming they were the original plugs.
I haven't touched my distributor & I don't plan to unless it breaks.
So the timing is stock.
I haven't finished the passenger side plugs & wires yet. The car seems
to be running really well now though. The passenger side plugs almost
make me miss my old integra. I could change the plugs & wires in 5 minutes!
If the car runs better with some fresh plugs then I believe you found your answer.
Dan is right though about the sensors, but it would depend on whether or not the sensors were reading a higher or lower temperature. I would say lower considering most times when a sensor acts up, it receives less voltage which would make sense as the ecu will think the engine is running at a cooler temp than it actually is, or breathing air that is cooler, and will run a higher ignition advance. But i really dont see there being enough compensation error to make the engine detonate. You've got a pretty stock engine and im sure GM took these errors into consideration when coding the ignition compensations....but maybe not lol
Okay, I feel stupid now. I knew that the LS1 engines didn't have a
distributor at the back of the engine like the old small block chevy
engines did. I just assumed that there was some sort of ignition
control module somewhere under the hood.
Is the engines ignition just controlled by the ECM?
BTW, thanks for the help. If I get the tune-up done & I still have
issues I'll check into the sensors.
distributor at the back of the engine like the old small block chevy
engines did. I just assumed that there was some sort of ignition
control module somewhere under the hood.
Is the engines ignition just controlled by the ECM?
BTW, thanks for the help. If I get the tune-up done & I still have
issues I'll check into the sensors.
jk jk
So what happend? did the detontion go away completly?
this is exactly what I am experiencing. was going to start with NGKs tr55s car has 40k on it. had a old hypertech program on it took that off and still did it. I will try plugs and fuel filter first.
this is exactly what I am experiencing. was going to start with NGKs tr55s car has 40k on it. had a old hypertech program on it took that off and still did it. I will try plugs and fuel filter first.
if I try. I feel a little bit better since I read in my cars manual that this
sort of noise is normal & is nothing to worry about unless it gets louder.
After I did the tune-up, my engine seemed to run better. The exhaust
sounds better. My engine ran fine before, but it just seems to idle so
much smoother now.
Good luck man.
A properly running engine should never ever detonate. Its not normal. Detonation destroys engines.
If you're getting detonation ONLY in high temperatures, and only when you try to accelerate...your pistons most likely have burnt oil built-up on their surfaces. These build-ups get hot spots after the engine gets hot, and the hot weather just makes it worse. Those hot spots will ignite (pre-ignition) the fuel/air mixture while the piston is on its upstroke and obviously before the spark plug fires. Thats "detonation". Crankshaft is ramming the piston upward, the pre-ignition is trying to blast the piston back downward before it reaches TDC. It crushes the connecting rod bearings and stresses everything.
Do you have any smoke trails when you stomp the gas pedal from a roll?
Or when you let off the gas pedal after a hard top end run?
The engine in the pics below had detonation issues ONLY when it got hot in the summer. It had leaky valve seals. It ONLY detonated when it was accelerated too, never at any other time. In the winter or at night when it was cooler it didn't detonate either.
Took the heads and got them rebuilt, valves were all bad, it was the ONLY thing that was done.
Then the pistons were cleaned. Thats it. No more detonation, NO MATTER how hot it was outside and how hard it was driven after the cleaning. That was the cause of the detonation.
.
If you're getting detonation ONLY in high temperatures, and only when you try to accelerate...your pistons most likely have burnt oil built-up on their surfaces. These build-ups get hot spots after the engine gets hot, and the hot weather just makes it worse. Those hot spots will ignite (pre-ignition) the fuel/air mixture while the piston is on its upstroke and obviously before the spark plug fires. Thats "detonation". Crankshaft is ramming the piston upward, the pre-ignition is trying to blast the piston back downward before it reaches TDC. It crushes the connecting rod bearings and stresses everything.
Do you have any smoke trails when you stomp the gas pedal from a roll?
Or when you let off the gas pedal after a hard top end run?
The engine in the pics below had detonation issues ONLY when it got hot in the summer. It had leaky valve seals. It ONLY detonated when it was accelerated too, never at any other time. In the winter or at night when it was cooler it didn't detonate either.
Took the heads and got them rebuilt, valves were all bad, it was the ONLY thing that was done.
Then the pistons were cleaned. Thats it. No more detonation, NO MATTER how hot it was outside and how hard it was driven after the cleaning. That was the cause of the detonation.
.
I know from working for a GM dealer when GM had these engines (LS series) alot of them Corvette, camaro, silverado, ect, had start up noise that went away after running for awhile, which was said it was "piston slap" or carbon on the pistons. They would pull the plugs and dump a cleaner in and let it sit over night, then start it and it would smoke for awhile. now we do this fuel injection flush which I had done 5 yrs ago couldn't tell if it helped. anyway it came back, so the only way to get it completly off the pistons is pull the heads? It will eventualy come back right?
I know from working for a GM dealer when GM had these engines (LS series) alot of them Corvette, camaro, silverado, ect, had start up noise that went away after running for awhile, which was said it was "piston slap" or carbon on the pistons. They would pull the plugs and dump a cleaner in and let it sit over night, then start it and it would smoke for awhile. now we do this fuel injection flush which I had done 5 yrs ago couldn't tell if it helped. anyway it came back, so the only way to get it completly off the pistons is pull the heads? It will eventualy come back right?
.
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A properly running engine should never ever detonate. Its not normal. Detonation destroys engines.
If you're getting detonation ONLY in high temperatures, and only when you try to accelerate...your pistons most likely have burnt oil built-up on their surfaces. These build-ups get hot spots after the engine gets hot, and the hot weather just makes it worse. Those hot spots will ignite (pre-ignition) the fuel/air mixture while the piston is on its upstroke and obviously before the spark plug fires. Thats "detonation". Crankshaft is ramming the piston upward, the pre-ignition is trying to blast the piston back downward before it reaches TDC. It crushes the connecting rod bearings and stresses everything.
Do you have any smoke trails when you stomp the gas pedal from a roll?
Or when you let off the gas pedal after a hard top end run?
The engine in the pics below had detonation issues ONLY when it got hot in the summer. It had leaky valve seals. It ONLY detonated when it was accelerated too, never at any other time. In the winter or at night when it was cooler it didn't detonate either.
Took the heads and got them rebuilt, valves were all bad, it was the ONLY thing that was done.
Then the pistons were cleaned. Thats it. No more detonation, NO MATTER how hot it was outside and how hard it was driven after the cleaning. That was the cause of the detonation.
.
If you're getting detonation ONLY in high temperatures, and only when you try to accelerate...your pistons most likely have burnt oil built-up on their surfaces. These build-ups get hot spots after the engine gets hot, and the hot weather just makes it worse. Those hot spots will ignite (pre-ignition) the fuel/air mixture while the piston is on its upstroke and obviously before the spark plug fires. Thats "detonation". Crankshaft is ramming the piston upward, the pre-ignition is trying to blast the piston back downward before it reaches TDC. It crushes the connecting rod bearings and stresses everything.
Do you have any smoke trails when you stomp the gas pedal from a roll?
Or when you let off the gas pedal after a hard top end run?
The engine in the pics below had detonation issues ONLY when it got hot in the summer. It had leaky valve seals. It ONLY detonated when it was accelerated too, never at any other time. In the winter or at night when it was cooler it didn't detonate either.
Took the heads and got them rebuilt, valves were all bad, it was the ONLY thing that was done.
Then the pistons were cleaned. Thats it. No more detonation, NO MATTER how hot it was outside and how hard it was driven after the cleaning. That was the cause of the detonation.
.
or after a WOT run. My engine runs really well. It only has 78K miles. I have
never had any internal problems. I hear a slight valvetrain type noise on
startup, but it goes away once the engine reaches operating temperature.
I wondered if my heads were worn & letting oil into my combustion chamber.
I just assumed that if that was the case I would see smoke on startup
or at WOT.
My engine uses about 1/2 a quart of oil over the 3K mile duration. I have
heard that the PVC system can cause oil to get into the combustion chamber
& cause this problem. Do you think that may be what my problem is?
If I do have built up oil & carbon build up on my pistons, what's the best
way to remove it? (Short of removing the heads).
I tryed using Lucas fuel treatment. It didn't really seem to help.
I appreciate the help.
BTW, I agree with you completely that detonation isn't normal. You have
to love the way that GM put that in the manual to cover their butts.
They probably didn't want to have to deal with these issues under warranty.
I don't have a single drop of oil going into my intake anymore. I stopped all that bullshit this week. I change my oil every 2,500-3,000 miles, so venting my crankcase using the ridiculously strong suction of the vacuum port on the intake, just sounds like another dumb design by GM. And there are MANY.
In the attached pics you can see the 3 black caps on the PCV ports. 2 on the intake and 1 on the valve cover. Then I put a filter on the port that comes from the valley cover.
If I do have built up oil & carbon build up on my pistons, what's the best
way to remove it? (Short of removing the heads).
way to remove it? (Short of removing the heads).
This is the can:
BTW, I agree with you completely that detonation isn't normal. You have to love the way that GM put that in the manual to cover their butts.
They probably didn't want to have to deal with these issues under warranty.
They probably didn't want to have to deal with these issues under warranty.
One more thing. If I were you and suspect burnt oil build-up on my pistons....I would take all 8 spark plugs out and spray the Mopar stuff directly into the spark plug holes and fill the pistons. You can use that same 3/8" hose to help reach the hard-to-get plug holes. Then, put the spark plugs back in just a couple turns with your fingers. Wait the 1 hour. Then take the sprak plugs out and turn the engine over for just 1-2 seconds. That will blast some of the foam out of the spark plug holes. Then put the plugs back in ans start it up.
.
Last edited by LS6427; Nov 29, 2009 at 07:02 PM.
