Knocking, Pinging, or just dumb noise?

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OK.. I'm perplexed.
For the past two summers, whenever the outside temperatures are 90 or above and I'm giving my '96 some gas under a long load (like going up a small hill near my house) , I hear what I think is engine knock.  I say I think because I've never heard it anywhere else.
I've done some youtube searches to find a similar noise. It is NOT a constant hard noise like this:
watch?v=-Gq9G...eature=related
It is throttle and load based. Revving the engine with no load will not do it. No noise at cruise. Only at load, over around 3000 RPM.  Needless to say I have modified my driving style to not include actions that make this noise.
When I hear this noise, there's no loss of power, stumble, hesitation, or anything that would make me think quot;it's firing too early.quot;
According to a borrowed Scangauge, my timing is 10* on the nose, so there's no chance I used the wrong crank notch to set the timing at some point.
I run a 12-gallon-size bottle (you know what I mean)  of Techron about once a month.
I've done the water and seafoam cleaning, and even though I followed the instructions carefully I don't see the quot;black streamsquot; in the driveway afterwards.
I've checked the timing again with dipstick and timing light. Still where it's supposed to be. And I did jump the diagnostic connector.
I've used the Search function until I wore it out.
What should I try next?

If you let off the gas and it goes away than its just spark knock...its 13 years old, probably loss a little compression....Rog

Rog -- that is indeed the case. If I let up on the gas, the noise in question stops.
quot;Spark Knockquot; is a new term to me -- what does that mean?

You can either retard timing a little or run higher octane fuel.  My 96 will do the same if I advance timing past 13 degrees.


Originally Posted by RADOne
You can either retard timing a little or run higher octane fuel.  My 96 will do the same if I advance timing past 13 degrees.

What he said...engine knock...spark knock ..same thing..try better gas first thats easier..if you retard the ignition it will in effect give you a little more torque a little less top end....or enter the hill at a higher speed....Rog

All of what you have described is a classic case of detonation. Don't confuse it with quot;pre-ignitionquot; which I suspect you are alluding too with your comment about quot;firing earlyquot;.
Simply put, detonation is an uncontrolable explosion of the fuel charge. A fuel charge, under extreme heat amp; pressure, which can be from a number of causes, many of which you have noted in your post, simply lights itself off without the assistance of an electrical charge across the electrodes of a spark plug. Heat amp; pressure from those sources simply exceed the kindling temperature of the fuel itself, and BANG, off it goes.
How to eliminate it? Most readily available cure is to raise the octane of the gas you are using. If you are on a diet of 87, try the next one up and keep going up in octane until the pinging disappears (hopefully!). More expensive, yes. Better than an engine job that could require new valves, pistons and rods. Detonation left unattended can be very destructive and costly.
Second solution: Don't drive the car on hot days. Notice how the pinging will all have completely disappeared when you drive the car on a cool and/or moist day. It's all about heat, heat and more heat. Heat from the outside and heat from the inside.

I was just searching some more...
In another post, someone wrote:

Is the EGR valve working? If not, this can contribute to high combustion chamber temps and pinging.

I *did* get a CEL for an EGR valve crapping out a while back the other day but haven't had time to attack it.
Hmm.. (Murph starts to do happy dance)

Wait a minute then...
Are Engine/Spark knock and pinging two different things?   Post #2 seems very laid back and quot;don't worry about it,quot; but everywhere else I hear that pinging/enging knocking can destroy an engine rather quickly.
I need this explained to me in kindergarden terms... because there's something I'm just not understanding.  I do understand Detonation much better now.

Pinging and knock are terms generally referring to the same phenomenon. An audible condition. Pre-ignition simply refers to a condition which has lit the fire earlier than the physical settings present in the engine. No audible change/difference than when the fire is lit at the proper time. Pre-ignition is also very dangerous if allowed to exist, capable of causing burnt valves and/or ventilated pistons. Again, as with detonation, the main culprit is heat, heat, heat.

Not sure if this is the problem you are having, but a few weeks back I filled up at a station that I had never used before. Soon after I started to hear quot;pingingquot; at low rpms under load, like when starting from a stop in a hard turn with the AC running, going up a small incline at low speed amp; low rpm.
I ran the tank down to about half and refilled with higher octane fuel. The quot;pingingquot; soon stopped. Not sure if I just had bad fuel or if fuel the was low on octane for some reason.
Bottom line I guess is try another fuel supplier if you use the same one all the time.
You may want to quit adding all the quot;extraquot; stuff in the tank as well.

That pinging under load will also go away if you stop lugging the engine down too lower RPM...downshift to a lower gear and see what happens.  We live in an area with hills..including a nice steep long one in my neighborhood...grab a lower gear...and get the motor in it's happy place.
All of the other suggestions apply also...but grabbing a lower gear is more fun...

Several good suggestions on how to cure knock - keep engine revs up, higher octane gas, retard timing a little more, etc.  Just DO NOT ignore it, it is doing damage to the engine, sometimes significantly.
Another question - you mention your scangauge is showing 10 degrees advance.  I don't believe that is your static timing and therein could lie your problem.  10 degrees advance MUST be set with the ECU out of the loop with the test wire between the test engine and ground ports on the diagnostic pedestal.  Check your timing, with a light, at the crank, with the ports connected and made darn sure the static timing is actually 10 degrees.  If you find it at 12+, you know where your problem is.

This is all great advice -- thank you everyone for your inputs.
Tom -- you questioned the scangauge usage. I did have the Diag ports paperclipped and held the scangauge where I could see it (outside the car)
I will check it with a strobe though as soon as I am able.
Just for trivia... the other night the temps dipped down into the 70's and I could not MAKE the engine knock.  This makes me lean towards the heat-related suggestions, but I will check the timing for sure.