motochris

damn dude i like your post you got resoures to back up what your saying just like they teach us in school. so what is the machine-gun sound is it just the car missing or somthing

d16tuner

Dude, I'd probably have to hear it, but from your description it does sound very much like knocking. When do you hear it? Engine hot or cold? Accelerating hard or at part/light throttle? What kind of rpms and engine load (hills, etc) when it happens? What is your timing set at? Give us more info to work with. Some pinging under a load is normal, not good, but normal. Heavy knock like it sounds like you are describing is very bad. All I can tell you is to give as much detail as you can. If your plugs are white, I'm pretty sure that signifies a lean condition. You are getting a little more air into your engine than stock. Even if the engine is in good shape, you might need to retard the engine slightly to make up for it. Running higher octane gas wouldn't be out of the question either. Dr. Boost could be right and it might not have enough mods to be running lean, but then why are your plugs white? I'm not a mechanic but maybe I can give you some ideas.

Try buying Chevron or BP or something like that for awhile since they are supposed to have better additives and see if that helps clean stuff up if you've got carbon buildup from driving hard. Or use some engine cleaner. This is my first bet.
Try retarding your timing a couple of degrees.
Since you are replacing them, try colder plugs
Make sure the cooling system is working properly to keep you from overheating. Flush your radiator if you haven't done it (I need to do this to )
Try higher octane fuel for a while and see what happens.
If you are running lean, none of those things should help, they might keep you from knocking tho.
Injector cleaner/new injectors might help, or a fuel pump like someone said. It'd probably be hard for anyone to say much more without more details, me anyway.

For misfire, check plugs, wires, rotor, cap, etc.
Does it idle rough even after warming up, and is your power down? To me those would indicate a misfire.

I am having trouble seeing why it would be knock tho if you never ping. Even going up hills without downshifting? And the fact that it is so infrequent makes me wonder what it could be too. Wierd.

Oh yeah, and check your compression. It can tell you a lot about how healty your motor is.

Do some searches on plug misfire and knock and associated things on the net and see what you come up with.

motochris

the machine gun sound is from the exuast at low rpm (about 1-3,000 rpm) it seems it does it more after i get done driving hard i did some research could it be pre-ignition?

d16tuner

yeah. sounds like it. I just realized that you are probably pinging a lot and just can't hear it over your exhaust. I have stock, so this isn't a problem for me. That is where I'd most expect to hear knock -- in the low to mid rpm range. I've got the same problem since I went with the AFC and larger injectors for some reason. I need to get mine figured out too before I blow something. Mine just does it when it is cold, I assume because it is running lean until the cat warms up. That is my theory, but I have no idea if it is right. I know the ignition is being advanced too by the afc, and that probably isn't helping. As long as I let it warm up, it is ok. But mine pings a lot under load, and when I changed out the injectors I noticed the inside of the manifold was totally coated with nasty black crud, so I'm thinking I need a good cleaning bad. I need to find another compression tester that will actually fit the plug holes in the head so I can get started diagnosing. I want to rig up an oil catch can too. I'm not using a lot of oil really, but I'm not convinced blowby isn't a large part of the problem. The compression test will help. Either rings, or I'm thinking my intake valves must be in REALLY bad shape for the mani to look like that...

Dr.Boost

Ok, if you will do me a favor and read ALL of my posts, I clearly stated that he should check his timing. I also stated that he should check his head gasket. He did not sound like he wanted to hear that. He quickly shot me down and ignored my help. Using a higher octane gas was not my only advise so stop saying that. Read the post before you make another comment like that. I assumed you had some experience in turbocharged engines and knew how important high octane fuel is in such an enviroment. Excuse me for giving you too much credit. Am I a gasoline salesman? Are you? I'm not the one with the gigantic summary of gasoline uses and engineering. As for my imaginary friends, what the ---- does that have to do with anything and where did that come from? Was that supposed to be a personal insult or something? Try harder next time because that was very weak.

Anyways, I never said anything about the octane being a "fix-all" for his engine problems. I simply advised him to try it and see what happens. Go ahead and re-read my posts now. He obviously isn't going to take the advise of anybody who tells him something he doesn't want to hear so I give up. Most people appreciate the help of others. I offered my help and it was ignored. ---- it. Good luck fixing the problems.

If you would like to argue with me any more, please use the PM feature so I can delete it and save myself, and any other members that have been subjected to this bullshit, the brain cells that would be lost. Thank you.

BTW, in your first post in this thread you recommended using higher octane gas as a fix:
Your second post was the complete opposite and contradicts your first post:
So why are you even arguing with me? It seems as though you jumped on my ---- for ***** and giggles. Get off my nuts please.

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89dxhunchback

I love that old stupid mith about 93oct. being better, haha..

My Mom used to tell me she got better gas milage using 93oct !!

The only way I would run 93' on a stock honda motor would be if it has nitrous sitting and waiting to be used.

d16tuner

Yes, you did say other things too, and yes I did mention octane. No I didn't mean that as a personal insult and I'm sorry you took it that way. I try to keep my insults to a minimum. I'm not here to start fights, but when you called me ignorant, that ticked me off a little. No I wasn't contradicting myself - just trying to present the "whole" truth as I see it. Half the truth doesn't do much good.

Using higher octane gas is one way to decrease ping/knock. Any idiot realizes that. I'm currently running 89 in a more or less stock civic. However, this is not the BEST way to keep a NA engine running well. I am not against 93 octane fuel, and if either he or I was boosted, I would say, "yes this is probably a necessity, and if you are pinging, you are stupid for trying to be cheap." But, to insinuate that "---- gas" was "causing the problem" is retarded. I just wanted him to realize that the gas is only a bandaid on his engine and that he should look further into what was actually causing it. since things that cause pinging can damage his engine even if it doesn't ping because of the fuel he is using. I never said he couldn't use higher octane to stop the pinging, as you quoted me, I said it probably would. However, I didn't want him to think that higher octane gas would fix his engine. I wasn't attacking all of the help that you were giving him, just that one simple comment that was actually made by someone else but which you seemed to support. And you wanted to jump all over that acting like I'm some sort of idiot with all your eye rolling and whatnot. That is all I'm saying on the topic. Your nuts? Grow up already.

Moto, adding higher octane fuel for awhile IS one way narrow down what your problem might be. But it isn't the only, or even the best way. If you don't seriously want to get your hands dirty, or retard your timing any, it may be the only way to get your car to stop pinging. Otherwise, try some of the things I and others have mentioned, and if you are still stuck, keep asking around.

Dr.Boost

Yeah, ok captain contradiction. Just drop the subject before you tell me to grow up. :P (sarcasm)
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d16tuner

Mine *appears* to be running lean as well. I has been detonating if I drive it before it warms up, and it pings worse than ever when I even get close to lugging it. I just installed the safc and some injectors. The plugs have always looked good before, but when I just pulled them to do a compression test, three were pretty white. #3 looked ok. The compression on the first two was 185, #3 was 175 and #4 was 195. That is (barely) within ok specs, so I think my rings, gasket, etc are in decent condition, unless all 4 are really low. What are the normal compression figures on a new/used honda engine, anyone know? I know running lean isn't the ONLY thing that can discolor the plugs that way, so I'm gonna have to check into it some more now...