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Discussion Starter #1
I know this may sound a little stupid but I have a question.
I recently bought an 02 truck that had a 3 program DP tuner chip on it. I bought the truck from a lot and could not get the original owners name so Jody could tell me what was on the chip. The truck's only Mod presently is the chip and there is a K&N drop in filter in the box.
Setting one on the chip is obviously stock. In setting #3 the truck will really run well and throw out some black smoke will you floor it. What I really like about setting 3 is the throttle response is really nice.
In setting 3 when you tip into the throttle the injectors really get loud over the stock setting. Now for my question, What is going on mechanically to make them get so loud when you tip into the throttle?

Thanks
Rob
 

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Going Crazy
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i think if the chip was sent to jody he would be able to tell you whats on it... as for the noise im not 100% sure but i think thats a change in timing you are hearing
 

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Discussion Starter #3
That was my guess, it is the injection timing. What I do not understand is why it is louder? All I can figure is the injector is having to inject against higher cylinder pressures which is harder on the injector and produces more noise???
 

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I know this is not what you asked but you need to know.
have a look at your air filter box, are the hold tabs broken ?
if so get a new air filter system asap .

cheap version is a napa 6637 filter 4" piece of exhuast and a couple of clamps, s&b seems too make a good affordable one , ford ais filters well (but need to add the 20$ fender sleave) if money is no object the afe2 is nice. if they are broken the let dust and debris in. This has tko'd a few blocks .
 

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If what you're hearing is timing advance...

The sound you hear is caused by injection delay actually. If you realize that a "diesel" engine is a compression ignition engine, then you see that the pressure/heat from the compression of the intake air charge approaching TDC is what ignites the fuel when the injection event takes place. Well, the pressure/heat can be expected to be less and less the farther and farther in advance of TDC you are. Meaning the cylinder is colder.

Is your truck louder when it's cold as hell and you just cranked it and started driving off, or when it's fully up to temp? Obviously when the cylinders are cold.

This is because when the diesel is injected, the cylinder environment is too cold to rapidly ignite the fuel. And while the fuel does burn, it does so at a very slow rate, allowing more diesel to be injected per time, than fuel being burned. It then fires off, making your engine sound noisy, and even emitting blue smoke when the ultimate temperature never gets high enough for complete combustion, such as on a cold engine, or one running severely reduced compression. What you hear, is the result of a cold cylinder not immediately burning off the fuel at or near the rate at which it's being injected. Because of this, you get a pocket of unburned fuel developing that will finally tend to "flash" off as you approach TDC and the pressure/temperature finally gets this pocket of fuel to "pop". And you hear it. This is not the injectors you're hearing, although they do make their own noise, no doubt.

When you inject the fuel at increasing amounts of advance, you are doing so into a colder and colder cylinder. Effectively increasing the delay between start of injection and rapid combustion. And in so doing, creating a larger and larger volume of fuel as of yet unburned.

Long story short, the sound you hear is the rapid combustion of a pocket of fuel. If advanced far enough, a drop in cylinder pressure will be noted, followed by a VERY large rise in cylinder pressure accompanying the "flash" of burning diesel that had collected when the cylinder was too cold to rapidly burn it.

Maybe that makes sense to you, or maybe not. But I can see no better explanation for the data I have seen and gathered myself.
 

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Smarty Power!
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If what you're hearing is timing advance...

The sound you hear is caused by injection delay actually. If you realize that a "diesel" engine is a compression ignition engine, then you see that the pressure/heat from the compression of the intake air charge approaching TDC is what ignites the fuel when the injection event takes place. Well, the pressure/heat can be expected to be less and less the farther and farther in advance of TDC you are. Meaning the cylinder is colder.

Is your truck louder when it's cold as hell and you just cranked it and started driving off, or when it's fully up to temp? Obviously when the cylinders are cold.

This is because when the diesel is injected, the cylinder environment is too cold to rapidly ignite the fuel. And while the fuel does burn, it does so at a very slow rate, allowing more diesel to be injected per time, than fuel being burned. It then fires off, making your engine sound noisy, and even emitting blue smoke when the ultimate temperature never gets high enough for complete combustion, such as on a cold engine, or one running severely reduced compression. What you hear, is the result of a cold cylinder not immediately burning off the fuel at or near the rate at which it's being injected. Because of this, you get a pocket of unburned fuel developing that will finally tend to "flash" off as you approach TDC and the pressure/temperature finally gets this pocket of fuel to "pop". And you hear it. This is not the injectors you're hearing, although they do make their own noise, no doubt.

When you inject the fuel at increasing amounts of advance, you are doing so into a colder and colder cylinder. Effectively increasing the delay between start of injection and rapid combustion. And in so doing, creating a larger and larger volume of fuel as of yet unburned.

Long story short, the sound you hear is the rapid combustion of a pocket of fuel. If advanced far enough, a drop in cylinder pressure will be noted, followed by a VERY large rise in cylinder pressure accompanying the "flash" of burning diesel that had collected when the cylinder was too cold to rapidly burn it.

Maybe that makes sense to you, or maybe not. But I can see no better explanation for the data I have seen and gathered myself.
That explanation makes perfect sense to me.

On the blue smoke being emitted, should it do that on a stock tune? When I start my truck and it's cold for the first 30 seconds to a minute it has a decent blue haze coming out of the exhaust. It uses no oil, so is this the explanation? It also blows white smoke like a mother for about 5-10 seconds.
 

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If what you're hearing is timing advance...

The sound you hear is caused by injection delay actually. If you realize that a "diesel" engine is a compression ignition engine, then you see that the pressure/heat from the compression of the intake air charge approaching TDC is what ignites the fuel when the injection event takes place. Well, the pressure/heat can be expected to be less and less the farther and farther in advance of TDC you are. Meaning the cylinder is colder.

Is your truck louder when it's cold as hell and you just cranked it and started driving off, or when it's fully up to temp? Obviously when the cylinders are cold.

This is because when the diesel is injected, the cylinder environment is too cold to rapidly ignite the fuel. And while the fuel does burn, it does so at a very slow rate, allowing more diesel to be injected per time, than fuel being burned. It then fires off, making your engine sound noisy, and even emitting blue smoke when the ultimate temperature never gets high enough for complete combustion, such as on a cold engine, or one running severely reduced compression. What you hear, is the result of a cold cylinder not immediately burning off the fuel at or near the rate at which it's being injected. Because of this, you get a pocket of unburned fuel developing that will finally tend to "flash" off as you approach TDC and the pressure/temperature finally gets this pocket of fuel to "pop". And you hear it. This is not the injectors you're hearing, although they do make their own noise, no doubt.

When you inject the fuel at increasing amounts of advance, you are doing so into a colder and colder cylinder. Effectively increasing the delay between start of injection and rapid combustion. And in so doing, creating a larger and larger volume of fuel as of yet unburned.

Long story short, the sound you hear is the rapid combustion of a pocket of fuel. If advanced far enough, a drop in cylinder pressure will be noted, followed by a VERY large rise in cylinder pressure accompanying the "flash" of burning diesel that had collected when the cylinder was too cold to rapidly burn it.

Maybe that makes sense to you, or maybe not. But I can see no better explanation for the data I have seen and gathered myself.
That Charles, is one of the best explanations I've seen you post. Didn't even offend anyone either :poke:LOL
 
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