Carbon deposits in the combustion chamber can do it also (ignite the end-gas). Without a borescope you might be able to see part of the top of the piston (when you take the plugs out).

 

New plugs and new gas (87 octane) and it's still doing it. I'm guessing the motor is carboned up. Any ideas on how to get some carbon out without pulling it apart? Someone also mentioned to me that a bad distributer could make it ping. The pining does seem consistant.

 

Sometimes you can help by using SeaFoam or some cylinder-cleaner stuff. Not used it myself, so lets see if someone else chimes in.

I don't see how a bad distributor can do that. Your spark timing is controlled using the sensors down at the crankshaft pulley. In an older Accord (before 1995), a flaky distributor can cause sloppy control of the spark timing. You can rule out spark timing anyway, by checking with a timing light. You won't be able to adjust the timing, but you can verify it's OK.

 

Check out series of videos on youtube by Chrisfix. He has tested several "cleaning solutions". My impression is that none did more than superficial carbon removal.

I have suggested chrisfix try water introduced into a vacuum line to "steam clean" and he plans this in future, but not done yet. There are videos by others who have done this w/o any proof of efficacy, but I have seen piston head from an engine w/ coolant leak and it was very clean, so this may be a useful option.

I am skeptical that cleaning will help, but it won't hurt anything. If carbon build up would cause pinging, we would see frequent reports on the forum. Your's is the first I've ever seen of pinging.

good luck

 

Ok, if it's pinging, will it do it when it's in park? It does it when it's in park between 1500 and 3000rpm. I does it also when driving between 1500 and 3000rpm. Maybe it's doing it past 3000rpm and I just can't hear it, it doesn't sound like it is. It only does it after it's warmed up though. There's just too much road noise to be able to tell past 3000rpm. Also, when I'm driving and I'm in any gear besides first it's impossible to tell if it's doing it or not, so I'm just going off of first gear and when it's in park. I guess this is getting to technical and I hope im explaining it right. I might just take it to my mechanic. Can maybe someone just answer if it does it when it's in park because if it doesn't do it when it's in park then I guess we can rule out pinging and call it a ticking time bomb. Thanks.

 

Suggest recording a video of sound and posting on youtube. This may help others ID noise source.

Or take to a professional. I've never heard pinging w/o load, but it should be possible.

good luck

 

Back in the 1970s I was goofing around with an old engine and dialed up the timing to the point where the engine was on the verge of stalling; never got it to ping with no load.

 

Yeah, I was thinking ping doesn't happen unless it's driving, but don't really know for sure. I can say I've never heard it. One thing that's weird is that it doesn't do it until it's warmed up. I was thinking about running thicker oil but everyone I talk to lately says that's a bad idea, but if it stops the knock wouldn't it be better since it's resonating? I'm now having second guesses. Maybe it's knocking and it's doing it after it warms up cause the oil is thinning out? I'm starting to think maybe I shouldn't have bought this car.

 

Worst case scenario; the motor needs to be swapped. Good condition used motors for your car are relatively inexpensive and plentiful.

 

I've heard "pinging sounds" from idler bearings (AC pulley, tensioner, Alt) on accessory belt, loose heat shields. These possibilities are much more likely than engine pre-ignition pinging.

good luck