REDIRECT -
The "ping" we're talking about is "preignition" or "detonation" - it's where the fuel/air mix is getting lit off before it's supposed to, and is caused by excessive heat retained in the conbustion chamber (caused by things being too hot to begin with or the wrong spark plug) or by the fuel/air mix being too lean (for thermodynamic reasons that would be the subject of another discussion.)
On that note, I don't see how a rich mixture could cause ping - the extra fuel causes a net loss of heat in the system due to the heat needed to evaporate the fuel - from fuel droplets to a true vapour. A lean mixture is FAR more likely to cause ping than a rich one. On that note, I'd think more along the lines of a good sound cleaning of the injector nozzles - either by running a few tankfuls of solvent thru them, or putting the pintle end into an ultrasonic cleaning bath and finding a way to trigger the pintle repeatedly (I guess some sort of timer or multivibrator could be built to do that - any takers from our electronics crew?)
If you can check your mix and verify if it is actually rich, I'd think more along the lines of going to a plug one or two steps colder.
(For the benefit of those of us who are not yet lifelong mechanics, referring to a plug as "hot" or "cold" means the speed with which the spark plug will dissipate heat into the rest of the engine. A "hot" plug has a longer porcelain nose and takes longer to bleed the heat off into the cylinder head casting, while a "cold" plug has a shorter nose and therefore a shorter path for the heat to follow. There is usually a digit in the part number to indicate the relative heat range of the plug, but you'd have to refer to the catalogue for your favourite brand for further explanation there.)
Carbon can be quickly seen to thusly...
1) Unbolt the flange ahead of the catalytic converter and use some method to pull the two pipes apart and out of alignment. You don't want to blow soot into the converter.
2) Disconnect the flexible intake air line from the top of the throttle body and pull it aside (you want the top of the throttle body exposed.
3) Start the engine, and have an assistant hold a fast idle (2000-2500rpm) with the accelerator pedal.
4) With a clean spray bottle full of distilled or R/O filtered water, spray a fine mist into the open throttle body at intervals. Watch the open exhaust pipe for results.
5) When you get no more soot, kill the engine and reassemble everything.
I used to have to do this on cars due to cheap gas, and I probably still do this about twice a year on general principle.
What happens - the water droplets get adsorbed into the carbon deposits upon intake. When the fuel/air mix is ignited, combustion temperatures approach 1000*F. Due to this the water is "flashed" into steam. Since the water is still adsorbed into the carbon, the deposits are blasted off of the various surfaces and blown out of the exhaust pipe. There are vehicles I have done this two where the black cloud I've gotten has scared the owner, but it ran so much better afterward...
The key is not to spray too much water into the intake - you don't need much, and you can always do the job again. You don't have any risk of hydrolocking the block, but why take chances?
5-90
in no way sanctions this.
