lb7 injectors loud under load and completely quiet once I hit 2900rpm ...???

[rcfreak24]

Mine does it at any rpm or throttle %.

My question is what is it and why does mine do it and the lb7 at work is quiet no ticking....

Makes no sense to me. I have heard of other people replacing injectors and they are even louder when they hoped for it to be quiet. There are many videos on you tube of loud injectors and kine sounds similar but idle is quiet and after 2900 rpm sounds quiet like the one at work which is a 03 also and it has never had injectors replaced. ...

 

[Hot COCOAL]

Mine does it at any rpm or throttle %.

My question is what is it and why does mine do it and the lb7 at work is quiet no ticking....

Makes no sense to me. I have heard of other people replacing injectors and they are even louder when they hoped for it to be quiet. There are many videos on you tube of loud injectors and kine sounds similar but idle is quiet and after 2900 rpm sounds quiet like the one at work which is a 03 also and it has never had injectors replaced. ...

Well, lots of possibilities have been suggested to you, with pilot timing being one of the more prevalent reasons for the sound you are hearing, without efi live or a tech2 scanner and the understanding of how it works, it's really impossible to decipher what your pilot and injection timing events are doing, other than making the truck run properly, but my guess is that they could be a little "out" either out of spec or not tuned perfect, and the truck would still seem like it's running fine but the injectors might be louder than normal. You running stock tuning? Sorry if that's been addressed already....

You run additives and have regularly maintenance the fuel filter so that eliminates that. You could try to run some two-stroke oil like some of the guys here do, and see if that makes a difference....can't hurt if mixed properly, and if the injectors quiet down it fixed it, or gives you ideas and options of what you might want to do...

I don't think it was mentioned, but modern diesel is pretty "dry" using proper methods to add lubricity to the fuel is a good idea, and might quiet those injectors down some, do you get fuel at the same place? Maybe try a new fuel source, and I think winter fuel is even worse, but I'm not sure? have you just recently noticed this "injector noise" maybe even the colder weather has some influence on the noise????

Whatever it is the truck runs good, so for now.....good luck

 

[TexasRob]

Don't know if some one has hit on this yet but since you said it was a government truck before you got it. I know a lot of government agencies specifically DOD run JP8 in their vehicles instead of diesel. JP8 is dry as hell, closer to kerosene than diesel.

 

[rcfreak24]

I wasn't aware of that. I'm not sure of the fuel before I got it.

I'll try adding 2 stroke oil and see if it does anything.

I will be tuning the truck soon and maybe that will help. I also plan on going to new larger injectors with in a month. Would be lovely if we could figure out why and how to quiet it down. I'll take a video next time I drive the truck

 

[rcfreak24]

Also it is the same if it's 10* out or 80* with engine hot or cold.

It was very noticeable when I first went to look at the truck before purchasing. I assumed it would need injectors. I paid attention to how it started ran and any smoking and nothing was alarming or of any indication the injectors needed replaced just loud. Some Schaffer fuel additive did quiet them some so I add more every time I get diesel.

 

[Hot COCOAL]

Also it is the same if it's 10* out or 80* with engine hot or cold.

It was very noticeable when I first went to look at the truck before purchasing. I assumed it would need injectors. I paid attention to how it started ran and any smoking and nothing was alarming or of any indication the injectors needed replaced just loud. Some Schaffer fuel additive did quiet them some so I add more every time I get diesel.

The only reason that I mentioned the cold, and this could be completely irrelevant, was that the fuel is going to be much more dense being so cold, and therefore would/could be causing the injectors to be doing more work to compress the fuel to the 22kpsi the stock tune requires, and therefor make a little more noise

Also, if the injectors are worn or older, the ball and seat of the injector could have some wear and I bet you would hear noise because of it. Tuning can have a noticeable affect on pilot timing, but I wouldn't change the injectors over it, you mentioned changing the injectors out in a month, you get what you pay for and there are definite "better than other" options out there. So don't just jump into a purchase.
:thumb:

 

[rcfreak24]

They will be from turbo diesel Injection in Indianapolis or exergy if I can afford. I have heard a lot of good about tdi injectors plus they are close.

I do not need to replace them because it starts and runs great has no issues. Was just hoping it would shut them up..

I'll add 2 stroke oil to it next time I drive the truck and see if it has any noticeable effects on the ticking.