Detonation or pining?

i got some kind of problem like this too. but i have been using 87 octane

I heard it when my car was being dynotuned. WORST sound EVER!! Made my damn toes curl, lol......

Sounds like hitting a metal pipe on a piece of metal REALLY fast.....something you don't want.

Run 91+ (preferably 93) octane gas. This alone will stop most pinging. Pinging or pre-ignition is very dangerous. It can be from too much timing, carbon build up on the cylinder heads, valves or pistons, cheap gas or any number of other things. Additional octane actual makes the fuel less volitale and lessens the chance of pre-ignition. The A/F mixture explodes before it's time (before the spark plug fires) while the piston is still in its compression stroke, essentially sending a sonic sound wave down the cylinder and rattling the cylinder wall and or piston, which is the sound you hear...now that sounds scary, doesn't it? I am not an expert by any means, and I'm sure someone could put this into better terminology, but this is basically what happens when your car pings. Avoid allowing your engine to ping at all costs.

Mine Pings too

I'm not to sure about the piston firing before the sparkplug fires since that is what the plug is for and you can't ignite the A/F mixture without the third side of the Flame Triangle (Fuel, O2, and Heat)

Mine is doing the same thing under hard acceleration above 4K rpms. I just put my first tank of Premium in tonight so we'll see how she runs over the next couple days.
It's got over 70K on what I think are the orginal plugs. I've got a set of Bosch platinums to put in just have to wait to get the chance........unless someone else local wants to do it for me??/??

twogt pretty much hit it!

There are a lot of terms floating around for this. Some people think they are interchangable and some do not: knock, ping, pre-ignition. They really all happen because of the same thing - fuel ignites due to pressure and heat before spark.

Older cars will start to knock/ping due to carbon build up. This makes the space smaller which results in an increase in pressure. All cars can knock or ping under the right conditions. Even if you have the proper fuel, under heavy load (towing uphill) and at full throttle on a hot day puts the car at greatest risk for this. Mustangs have knock sensors which help to prevent it.

If your car does this, you need to decrease your timing or use higher octane fuel. It is NOT a good thing.

I have detonation above about 5000 rpm and higher octane does help out a bit, but I think I have found out what the problem is. If you haven't listened to spreadmans dyno vid, listen to it...his was detonating at high rpms as well and it turned out he had a bad fuel injector. My car makes the exact sound under the same conditions as his did, so I figure I probably have the same problem.

chevylover said:

I'm not to sure about the piston firing before the sparkplug fires since that is what the plug is for and you can't ignite the A/F mixture without the third side of the Flame Triangle (Fuel, O2, and Heat)

Mine is doing the same thing under hard acceleration above 4K rpms. I just put my first tank of Premium in tonight so we'll see how she runs over the next couple days.
It's got over 70K on what I think are the orginal plugs. I've got a set of Bosch platinums to put in just have to wait to get the chance........unless someone else local wants to do it for me??/??

Click to expand...

The Flame Triangle? Hmmm, never heard it referred to in that way, but, OK... So which side of the "triangle" is missing? Heat? In an engine?
Or, how about in a diesel engine...they don't even have spark plugs. Gosh, how in the world do those things work?

By the way, thanks Go HoTO for defending my answers. In addition to increased CR, carbon build-up can glow like a red hot ember and fire the mixture.

millatime said:

I have detonation above about 5000 rpm and higher octane does help out a bit, but I think I have found out what the problem is. If you haven't listened to spreadmans dyno vid, listen to it...his was detonating at high rpms as well and it turned out he had a bad fuel injector. My car makes the exact sound under the same conditions as his did, so I figure I probably have the same problem.

Click to expand...

Got a link to the vid...I'd like to listen to it to see what your referring to.

Actually I found the vid but I'm not sure what exactly you were referring to in terms of detonation...are you talking about the beginning part?

http://users.ev1.net/~spreadman/Pages/media.html

twogts4us said:

The Flame Triangle? Hmmm, never heard it referred to in that way, but, OK... So which side of the "triangle" is missing? Heat? In an engine?
Or, how about in a diesel engine...they don't even have spark plugs. Gosh, how in the world do those things work?

By the way, thanks Go HoTO for defending my answers. In addition to increased CR, carbon build-up can glow like a red hot ember and fire the mixture.

Click to expand...

Very good!!! Diesel engines use glow plugs which must be heated before starting the engine so they will ignite the fuel and complete the triangle to produce a flame.

DeadLurker said:

Actually I found the vid but I'm not sure what exactly you were referring to in terms of detonation...are you talking about the beginning part?

http://users.ev1.net/~spreadman/Pages/media.html

Click to expand...

18 seconds into the dyno video. It's there.

Spreadman said:

18 seconds into the dyno video. It's there.

Click to expand...

It's also on the second part of the video: listen carefully when the car hits 5000rpm and you'll hear detonation as well.

Scotty is it still doing that? I just backed my timing off 2 degrees to keep it from doing that.