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Discussion Starter #1
I've been wondering about this for quite some time, but there was another topic recently about fuel additives that made me think about it. That topic said that some fuel condiitioners could reduce valve train noise. I had NOT been running any fuel conditioner in the summer, just in the winter (mostly for gelling purposes).


My truck has had the "tick" until about the last 2000 miles, and now it IS getting quieter. We have a Dmax at work, and it's signifigantly quieter than mine, and always has been, even when it was new. I've actually heard 6.5L's that are quieter than my truck.


With my last fill up, I added some PowerService Cetane booster/conditioner (it was available at WalMart, and I thought that it couldn't/shouldn't hurt). Now, I've noticed that the drivers side or my truck is MUCH quieter than it ever was (the side that used to tick), but the passenger side is much noisier than normal.


My question is really this. What is it that makes some engines quite a bit quieter than others, not including the tick? It's not really something that I'm concerned about because I had a Cummin(g)s
before this, and I'm used to a little noise
. With a Cummins, it was impossible to tell a quiet one from a loud one, because there's no such thing as a quiet Cummins before '03.


It's just one of those big mysteries of life that makes you go Hummmmmm...



cadman_ks
 

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My juice has been lent out to a friend for the last couple days. I really think my truck is quite a bit quite without it. Either that or it is just another side effect of withdrawl..
 

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I noticed that my truck was a bit noisier than CS-DMAX's truck when we got together a couple of weeks ago. Also found out that slight knocking at idle isn't present in his...



Not sure if it is the juice making the dmax louder or not...'spose I could take off the juice and see if she quiets down. Wish I knew what the knocking was though....once you rev it up another 100 or so rpms it goes away.


Bob
 

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Diesel fuel quality can very much affect our Duramax 'loudness' level. Lower cetane fuels, especially, can almost get to the pre-ignition level, robbing power, creating a clatter. One of the advantages of using a quality fuel additive such as Primrose 405 is that it not only significantly boosts cetane index but also creates a more even burn cycle in the cumbustion chamber. The combination of the increased cetane (delayed ignition) and burn modification combine to increase the power of the combustion cycle and also increases fuel efficiency.
GeorgeEdited by: Georgecls
 

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Discussion Starter #6
Georgecls said:
... The combination of the increased cetane (delayed ignition) and burn modification combine to increase the power of the combustion cycle and also increases fuel efficiency.
George

While I'll tend to agree with this statement, there's still more to the noise thing than just fuel. The cetane booster that I used on the last tank DID improve my fuel economy, so I know that it does help.


But, here at work, our Dmax gets fueled with WHATEVER is on the road or close. They don't stop at truck stops, they just get diesel whereever they can. There's NO possible way that the quality of the fuel in our work trucks is anywhere close to anything acceptable.


I however, ALWAYS buy my fuel from the local truck stop. I DO get better fuel economy with this fuel, so I know that it's of better quality than buying it just anywhere.


Even with the "good/better" fuel that I'm putting in my truck, my truck is STILL signifigantly louder than the ones here at work. There just seems to be a wide range of noise that comes from these engines, and I can't believe that it's all fuel related.


cadman_ks


PS: I do NOT have Juice or any box. I'm totally stock, and so are the work trucks.
 

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My next door neighbor has a 2001 XCab D/A like mine and we differed only in the fact that his is a 4WD, white,, and mine is 2WD, pewter. Trucks are parked 30 ft. apart in this CA subdivision.


Identically quiet and significantly quieter than the PSD 4 houses down until 6 months ago.


Neighbor had his truck lifted and added big tires. Definitely noisier since the lift. Still not enough to wake us up and certainly not the "Wake the Dead" PSD, but noticeable.
 

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In the older low pressure mechanical injection engines a sure sign that the injectors were getting dirty, like a varnish build up, was they would get noiser. Usually would pick up a knock like a rod knock at an idle. Why couldn't dirty/ going bad high pressure injectors do the same? My truck is getting noticably louder as it ages.
 

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Discussion Starter #9
a64pilot said:
... My truck is getting noticably louder as it ages.

The problem with my truck is that it ONLY has 13,000 miles (just turned last nite), and when it had the "tick", I couldn't tell how loud it really was. Now that it's gone, it seems louder than I have heard others.


Mine is a late production 02, so I'm pretty sure that I have the new design hardened injectors...


cadman_ks
 

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Discussion Starter #10
a64pilot said:
... a sure sign that the injectors were getting dirty, like a varnish build up, was they would get noiser. ... Why couldn't dirty/ going bad high pressure injectors do the same? ...

That kind of makes me wonder if I don't have an injector going out on the RIGHT side of my engine since it's noticeably louder than my left side.


That's something that I never thought of.


I bet that I would have to pull my dealers teeth to get them to do a balance check. While my dealer is really good about warranty work, they are NOT keen on checking things that I MAY think are wrong. They kind of have the wait and see attitude. I asked them once about making sure that my truck had all of the latest flashes on the TCM and ECM, and they said that they wouldn't do any of that unless there was some problem.



cadman_ks
 

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Georgecls,


Cetane index is a measure of the ability of the fuel to burn. In fact, it is the intervall between the beginning of injection and autoignition. The higher the number, the faster and easier the fuel burns.


Low cetane fuel tend to burn unevenly and slower, creating noise and smoke, and even rough operation of the engine. With low cetane fuel, the ignition sometimes is happening after TDC, which causes a too late pressure rise, incomplete combustion and accompanying power and fuel economy loss.
 

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I have a stupid newbie question. What are the ranges of cetane fuel for high milege quality? Cetane, I presume, is the gas equivalent of octane.





Thanks


Joe
 

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My truck started to get a bit louder around 35K miles. Has been the same ever since. It goes through louder moments from time to time, I notice it louder when AC is on which must directly relate to engine RPM and required fuel (Hence Injector duty cycle is reduced so they can be heard pulsing) After doing some research the consensus opinion has been that the injectors are the culprit. Now this does not mean they are bad, just means they are noisier than others. I use FPPP additive on and off but I live in California and the weather is always pretty consistent. I always buy from the same 2 fuel stations unless traveling.


Anyway I am not worried about it, I have 70K+ miles now and it still gets the same MPG and still runs at 80+ MPH without any problems...
 
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