Hi Everyone-
I have a 2007 CTD 2500 with 6 spd manual, and an Edge with Attitude.
Anyways....
When I get on it pretty good, it goes from sounding "normal" to ratteling alot and sounding like my 98 24 valve.
Is this injectors cycling rapidly, a timing change or something very bad?
It runs like a scalded chicken though- Lots of power and black smoke, no check engine lights, no trouble codes in the computer, but one of my buddies said something about turbo cavitation and scared the crap out of me.
Please reassure me....

 

I am not sure if you can actually cavitate a turbo. I am sure that Coal Train or Pizzo will post to correct me if wrong, but I dont think so. I run a Bullydog PMT and when I get on it good and heavy, the whole sound changes, of course. I run stacks, so the exhaust get hella raspy, the engine wraps alot quicker and makes some different noises. Thats jus my 2 cents.

 

Sounds like what you're hearing is timing rattle. Does it sound like someone poured a bag of marbles in the engine?

What level is the Edge on that you are hearing the noise?

If it's timing rattle, that's a BAD thing. Essentially what happens is the fuel pre-detonates and it tries to fire the cylinder backwards.

It usually doesn't happen unless you're on the highest settings and have the responsiveness of the Edge turned all the way up and have it stacked with something else. If I have my Smarty cranked up and have timing added, using the Edge (which also adds timing) causes nasty timing rattle. It's a good way to beat the crap out of your bearings and blow head gaskets.

And no, it's not "cavitating" the turbo, which is possible, but not likely. Actually what happens with a turbo is you stall it (hit the surge line). The fins on your turbo are just like the wings on a plane. Too fast or too slow and they're not efficient. Too slow and you have no boost. Too fast and you get drag, the compressor stalls and all you do is heat up the air.

Here is what stalling (hitting the compressor surge line) the turbo sounds like. Watch the screen on the dyno and you see the pressures spike badly. On a properly wastegated turbo, this rarely happens......

http://www.youtube.com/watch?v=nCj6Spwl1CU

What your buddy is talking about is turbo bark.

This happens when you go from high boost pressure and drive pressure (i.e. heavy throttle and load) to no drive pressure (exhaust). You end up with all the built up boost pressure on the compressor side and now you have no drive pressure on the turbine side. The built up boost now has no where to go and nothing pushing it, so it tries to come back out the compressor side and this quickly slows the turbo wheels down. This isn't good for the turbo and at elevated boost pressure (45 psi for a stock turbo) you can end up finding pieces of your compressor wheel in your intercooler.

This is what turbo bark sounds like. Listen at the first 4 - 6 seconds of this video and again at about 1:04.....

http://www.youtube.com/watch?v=cxqyxpx4cFQ

 

Doesn't sound like marbles at all.
It does it on all settings too.
Akmost sounds like my 98 sounded when you'd floor it and it would downshift. It's like the sound gets louder and more "intense". and it's hard to explain. Does it with out the Juice too.

 

Does it seem like it's ticking excessively at idle?

 

Nope. Doesn't tick at all.
I'm thinking I might just be over sensitive about it and am being a pansy.
I have heard that as throttle percentage raises, it sends the injectors into a higher cycle, and more fuel would explain a louder engine. Dunno??

Coal Train- Ever hear about injector cycles? Could that be it?
It doesn't tick at all, idles smooth, oil level hasn't changed a bit, no metal bits in the oil when I change it, doesn't run hot, no CELs, no weird smells, nothing. Just sounds like she's kickin it way up. Just hope it's nothin weird...

 

The injectors cycle 3 times per injection event on your engine.

It's just a fancy way of saying the it injects fuel 3 times as the piston come up to TDC.

This was done to reduce engine noise and lower the cylinder pressure spike from the main injection pulse.

Sounds like all you're hearing is the normal operation of the engine then.

The CR's, and especially the 6.7's, are so quiet compared to the previous engines that with a stock exhaust and intake, you hear every little noise it makes.

If you're really worried about it, take it into the dealer and have them hook the StarScan to it. It'll be like a $65 diagnostic fee, but have them run a cylinder contribution test and an injector kill test. The cylinder contribution test will show you if they are all performing equally and the kill test will isolate a misfiring injector.

 

Funny I was going to post a similar question today...

Mine too is an 07 5.9, but this is my first diesel truck so I was going to ask if this sound was normal. Mine makes a rattling sound like you explained above when the RPM's get up near 2500. Mine is just like an additional rattle/engine noise almost like loose rocker noice or something, but it comes and goes depending on throttle input, boost and etc. Mine is alos there at all different levels of th programmer even with it set back to stock so I wouldn't think it was preignition knock, but like I said I was going to post a similar thread asking if it was normal. Is this what you're hearing too and if so is this what people are saying is normal in these trucks?

 

OK, so I just got back from a test drive where I was trying to reproduce this sound and wasn't able to really reproduce it well, just heard it a couple times for less than a second. I took video of this so that I could post it here for you guys to let me know if it's normal, but again it is only a few seconds and this is my first time uploading videos to youtube, so not sure if the sound quality will be there, if anyone wants a better quality version for helping troubleshoot PM me and I will send it to you that way...

Crap, it looks like youtube has super slow uploads, it says my videos will not be uploaded for about 40 minutes...

I will put the links in this post when they finish uploading...

*** Edit ***
Well YouTube is pretty slow at uploading, I thought the estimate of 40 minutes was for both videos I uploaded, but it just apears that was only for the first one the second one says over an hour to upload...

Anyhow, you almost cannot even make out the noise I am refering too in these videos since they only did it for a quick second and wasn't really reproducable. But at just about 1:58 of this video you can kinda hear it...
http://www.youtube.com/watch?v=CevvcN5lSdQ

The only time I could really make out the sound here was around 1:16-1:17 of this video
http://www.youtube.com/watch?v=A0WUmNugrz0

 

I couldn't really hear it alot, but what you are describing sounds like what I am hearing.
I don't have stock exhaust, and I am starting to think it could even be the wastegate or something dumping extra exhaust or somethiong, because it does seem to be related to to boost.
I have the boost alarm on my attitude set at 36 psi, and when I hear the noise, I hear the boost alarm shortlt thjere after.

Coal Train- What levels of boost should I see with the edge?
And also, Thank you very much for all your help. I think it's really cool that guys that know as much as you do are willing to help guys like me. I appriciate it!