Admittedly, this is my first diesel. I own a 2003 2500 Duramax with 76K on it. I've owned it since it came off the lot and was initially impressed with how quiet it was on the road. About 15k ago, I thought it started sounding a little odd, so I took it to the dealer. From my description, they told me that it sounded like an injector problem and then charged me $80.00 only to later tell me that nothing was wrong and it was operating optimally.

Initially, I believed them, but the sound is starting to make me think something is wrong. It only occurs under load.....well, load being going up a hill or under heavy accelleration. I notice it more if I take off the overdrive, but I think that's because of the difference in rpm. This truck has been babied. I only tow about 4~5 times a year and only locally, so about 200~300 miles annual.

If you could, please listen to this mp3 clip and tell me if I'm just being nitpicky. The clip starts with me idling at a stop light and then just accelerating along a frontage road that's pretty level. It's not the best recording, but I think you can hear the "putt,putt,putt" sound allright.


Thanks

CLIP:
http://www.bettyfry.com/TR20060309-084840.mp3

sounds ok to me!
Mine sounds the same.

____________________________________

03 D/A SB GMC 4X4:ro)

I think the pilot injection turns off under high load. This is probably what is happening.

Sounds ok to me as well. what is it doing that it makes you think something is going on?

Tell us more:)

I can hear it kinda "rattle" a bit. At idle it sounds smoothe and then every once in a while it makes an odd rattle.


I don't know.

I could have sworn about 20k ago, I never heard the "putt,putt,putt" sound from the engine. It used to be a continuous low roar when accelerating. Now, it almost sounds like a exhaust leak. I'll try to get a better recording tonight. I drive up a steep hill where it really comes out.

i have heard of a putter sound before from a exhaust leak but the truck sounded great to me. Also could be the mic is not picking up the entire freq range of the sounds your trying to capture

Sounds like a stereo problem.......turn it up and you won't notice it anymore :lol:


Seriously, it sounds normal. The only thing I could think of that may be causing the variation would be the fuel pressure regulator.

I could have sworn about 20k ago, I never heard the "putt,putt,putt" sound from the engine. It used to be a continuous low roar when accelerating. Now, it almost sounds like a exhaust leak. I'll try to get a better recording tonight. I drive up a steep hill where it really comes out.

Same here. Esp on a hill. I couldn't really hear it in your sound clip, but from your description, our trucks make the same noise. Picking up my truck tonight from the dealer. Dealer told me on the phone its definately injector noise, but normal and all injectors fall within specs. Great... so I'll try a bottle of fuel conditioner (I've read here that it helps) and wait till it gets so bad they have to do something. At least its now documented.

Sounds like a stereo problem.......turn it up and you won't notice it anymore :lol:


Seriously, it sounds normal. The only thing I could think of that may be causing the variation would be the fuel pressure regulator.

Agreed dont bother with the fuel conditioner, just give that bose a workout. If i dont have music going i tend to listen to hard and try to find something wrong. Go by feel or if it wont run.

That might be why i'm hearing it now. I just recently installed an iPod adapter and now I'm listening to a mix of music and podcasts. The podcasts don't cover the noise up. :)

It doesn't sound right to me. I hear the tap tap tap noise. Mine does not sound like that. I had to put my ear right up to the speaker to hear it.

Could it be?

http://dieselplace.com/forum/showthread.php?t=54560&highlight=knock+load

Page 13 is where we found the cause/fix.

MC are you running any mods, ie: a power programmer or the like?? Mine used to sound as yours did 'til I started using Stanadyne's World Blend (lubricity formula) fuel additive and it does make my dmax run quieter. In all honesty your Dmax sounds fine. You still have plenty of warranty left so enjoy it and work the s$@t out of it as that's what it wants to do. I know from experience the harder I work mine the happier she sounds. Good luck.............SWH...

http://img.photobucket.com/albums/v508/shuffman/013WORLDBLEND.jpg

http://img.photobucket.com/albums/v508/shuffman/DuramaxSticker.jpg

Mine has been making the same noise recently. It's bone stock with 63K. I first noticed it about 2 months ago, shortly after the dealer performed the fuel filter recall (maybe just a coincidence). What's bothersome is that it used to sound smooth as silk, so something has definitely changed. Masking the sound by turning up the radio doesn't make me feel any better. I have run a couple of bottles of injector cleaner through the fuel with no results. I also tried the heater hose bracket bolt removal mentioned by tophog. I may try the Stanadyne lubricity formula recommended by shuffman. If anyone else has found a cure (besides injector replacement), I'd sure like to hear about it. I'm afraid it might end up being a bad injector, but not quite ready to bring it to the dealer.

Like Tophog said... CHECK THAT LINK!

I hear the knock. It sounds like an injector knock, which is usually accompanied by white smoke... But I would check that link 1st;)

shuffman, my truck's 100% stock. The only thing I've been doing out of the ordinary is running biodiesel. The noise started well before the BD though. As a matter of fact, I started running the BD to see if it would clear out the system which it did somewhat. Here's a picture of the filter after I ran about 3 tanks of BD through the truck. The filter got so clogged that my truck wouldn't go over 20mph one night on the way home.

http://i2.photobucket.com/albums/y15/mmoyer/IMG_3571.jpg

Like Tophog said... CHECK THAT LINK!

I hear the knock. It sounds like an injector knock, which is usually accompanied by white smoke... But I would check that link 1st;)


So if it is injector knock then it's not a big deal? Just disconnect that bracket and be done with it? Or am I reading you wrong.

Thanks

Could it be?

http://dieselplace.com/forum/showthread.php?t=54560&highlight=knock+load

Page 13 is where we found the cause/fix.

I've got some time allocated this weekend to try this fix out!

mcmoyer, mine has a knock like yours too and I tried the heater pipe thing that helped tophog and others. I could not tell a differnce when I did it. Your truck kinda sounds like mine but I also have an intermintent loud clatter to mine in the 1500-2000rpm range. It really sounds like a valve tapping real hard. I have taken it to the dealer and they say they hear the noise but don't know what to do to fix it. It seems like they only want to work on something if the techII tells them there is something wrong( i.e. only if the SES light is on). The dealer told me to keep driving it and thats exactly what I'm gonna do. The knock/tap I have sounds like fuel knock that is melting a hole a piston. I'm gonna drive it till one of two things happen. Its either gonna blow the engine or if that doesn't happen I'm going to take it back to the dealer right b4 warranty expires and demand they make the truck right! I have 69000 miles on it now so i guess I have another 30000miles to go on warranty. The noise is driving me nuts so its really hard to not take it back to the dealer and demand they fix it now. Needless to say I'm not a happy camper right now.

Got my truck back from dealer last night. They also admitted its injector noise, but said the Tech II didn't find anything out of sync to warrant any further repair. I had 'em change the fuel filter for the recall, and left without anything being done basically. At least its documented in their system now. If it gets worse or I get any other symptoms of injector failure, I will take it back to them and demand a solution. I am also going to try tophogs fix this weekend to see if that helps, but I don't have any noise at idle so I don't think that one is going to work for my truck.

I have the same sound under acceleration. Let me know if the coolant hose fix is it. Here's hoping.

shuffman, my truck's 100% stock. The only thing I've been doing out of the ordinary is running biodiesel. The noise started well before the BD though. As a matter of fact, I started running the BD to see if it would clear out the system which it did somewhat. Here's a picture of the filter after I ran about 3 tanks of BD through the truck. The filter got so clogged that my truck wouldn't go over 20mph one night on the way home.

http://i2.photobucket.com/albums/y15/mmoyer/IMG_3571.jpg

MC, mine does not have the knock and if BD is doing this to your filter I wonder what it's doing to the rest of your fuel system ie: the night you drove it home at 20 MPH how much of that sh#t got past the plugged filter. I'll stick with the plain ole diesel fuel with the Stanadyne additive. All seems to be well, knock on wood...............SWH

shuffman, that's what the BD cleared out. All that stuff is in your tank right now if you're using Dino Diesel. BD is just much more of a solvent that it cleans out the system as it runs through the system :)

Plus, there's nothing like making people standing by your truck start to sniff the air then look around for the nearest restaurant. :)

I've had this filter on for about 5k so far with almost exclusively B20 or B100. I did almost run out of fuel one day and ended up filling my tank with dino diesel. The real test will be to see what this one looks like in about 10k more! I was warned by the local BD distributor that I'd probably have to change out the filter pretty quick after the first ~5 tanks of b100. He was right.

Like Tophog said... CHECK THAT LINK!

I hear the knock. It sounds like an injector knock, which is usually accompanied by white smoke... But I would check that link 1st;)
It's a no go on the link. I did it today and didn't notice any difference...well at least not an appreciable difference. I don't notice any smoke, but given that I'm running BD, I really don't see much smoke even when I'm holding the pedal to the floor.

Is injector knock bad? Is it just the precursor to injector failure?

Admittedly, this is my first diesel. I own a 2003 2500 Duramax with 76K on it. I've owned it since it came off the lot and was initially impressed with how quiet it was on the road. About 15k ago, I thought it started sounding a little odd, so I took it to the dealer. From my description, they told me that it sounded like an injector problem and then charged me $80.00 only to later tell me that nothing was wrong and it was operating optimally.
CLIP:
http://www.bettyfry.com/TR20060309-084840.mp3

Heard a bit of what I think you were noting, but nothing that made me uncomfortable. Remember that the computer in the unit will make adjustments as you drive. I hear similar from mine. Remember that you'll be due for valve adjustment at 100K ... might take a bit of it away.

RJ

What did you use to record the sound? That's a good way to explain certain sounds and hear what some noises are. Mine sounded the same except after I had my fuek filter changed.

By listening to your clip, it sounds like a mechanical problem with an injector. I would use a T2 to cancel cylinders while driving to pinpoint the cylinder(s) creating the noise. I have seen this more than once and that noise you recorded sounds very similar.....Just my .02

By listening to your clip, it sounds like a mechanical problem with an injector. I would use a T2 to cancel cylinders while driving to pinpoint the cylinder(s) creating the noise. I have seen this more than once and that noise you recorded sounds very similar.....Just my .02

Hmmm.. I don't know what a T2 is.

What did you use to record the sound? That's a good way to explain certain sounds and hear what some noises are. Mine sounded the same except after I had my fuek filter changed.
I used my laptop with an external microphone on the dash. I thought it was a good idea myself :)

My wife just thought I was a geek.:lol:

A T2 Is Short For A Tech 2 The Type Of Scanner Gm Service, And Other Mechanics Use To Scan And Diagnose Vehicle Problems. To Use One Go To Your Nearest Repair Shop Or Gm Service Department.

T2 is a Tech 2. The GM scanner. Sorry for the confusion. Sometimes I get a little carried away:o:

Thats funny, my wife says I am borderline compulsive. I have to turn on my radio or else I find myself listening for pinging. Never thought a diesel pinged until I turned down my radio.
For the question at hand. I was in denial about my injector failure until my truck would not start anymore. I know that aside from the balance rates being out of spec. another telltale sign is the "exhaust leak" sound. After changing all 8 injectors it was like a new (quiet) truck again.
For what it is worth...if you are going to use anadditive try Amsoil cetane boost. I used it in my fuel tanker and could not believe the difference it made. Im sold on it.
Id take your truck in and tell them you want the balance rates checked because it is hard starting and when it fires it blows white smoke.
now:grd:

If you want to hear something scary, open the oil pour cap while the engine is running.

On my 02, it sounds like a little elf with a hammer and a tuning fork. Ringing pings, and I don't mean pings like most think of engine pings, but pings like you might think of when hitting a small pipe.

Screw the cap back in and is sounds like most, only it seems louder to me.

Bert

:blahblah: i know where you are coming from i think i had the same problem. i had a note in the forum duramax rattle,

in cold starts i noticed it the worst.
mine started when my trans went and the truck got stuck in 4th gear limp mode, if i rev'd up too much in 4th gear about 58 mph sounded like the waste gate would kick out or something loud hard rattle, then after the trans was fixed, i would hear it on hard throttles just when i let off or when i started to accelerate between gears.
it is more than likely a timing issue, low fuel maybe, i changed the fuel filter, fiddled with stacking chips, etc. and do not have the noise anymore.
i checked my injectors also, they were are in tolerance.
hope this helps.

Dont listen so hard, its a diesel and it sounds great to me!

it does sound strange to me, mine dont sound like that, mines smoother.