Picked up my brand-new Sierra 2500HD Duramax/Allison last month. Other than a squeaky drive belt, no problems ... BUT today on the freeway, driving unladen, 1660 miles on the clock, there was a LOUD "clacking" noise coupled by a very noticable loss in power!


It was brief, then went away ... happened again about 1-2 minutes later. Again it was a brief, LOUD "clacking" noise and power loss ... then the truck seemed to recover and ran normally again. I drove another 10-15 miles on the freeway and ~6 city miles before getting home and nothing happened the rest of the trip - ran perfectly.


QUESTION: this is my first diesel - could the loud 'clacking' have been some water, or otherwise contaminated fuel passing through the injectors and causing the engine to sputter momentarily? Once the contamination passed, the engine again ran normally?


I called On-Star just to see if anything was logged in the computers they monitor & there was nothing recorded on their end.

How fast were you going? Were you going around 85 mph? Around that speed the pilot injection shuts off and your normally quiet Duramax starts sounding like a PS or a CTD. There shouldn't be any noticeable loss in power when the pilot injection shuts down.

I don't think I was going 85 ... more like 70. Southern CA freeway interchange speed. I remember the tach was around 2100-2200 just after the incident.


This really didn't sound like a normal noise ... very loud & it felt like the motor was sputtering & trying to quit. Very brief though - noise just lasted a couple seconds, 1-2 minute pause ... then a couple seconds more of the noise/power loss thing ... then back to normal all the way home.


...!?

Here is more info re: pilot injection...


http://dieselplace.com/forum/forum_posts.asp?TID=8165&KW=pilot+injection+

That loud clacking noise and loss of power is exactly what my truck did when the #1 injector stuck open. Did you notice a lot of smoke out the tailpipe?


I hate to say it, but I suspect you have a sticky injector. The good news for you is that, from what I understand, they're changing all 8 now. I missed that TSB by two weeks.http://www.dieselplace.com/forum/smileys/Cry.gif


If it sticks open, I'd kill the motor ASAP, or ...


run it til it dies.


BTW, mine threw no codes when the injector went.


Rick

That loud clacking noise and loss of power is exactly what my truck did when the #1 injector stuck open. Did you notice a lot of smoke out the tailpipe?


I hate to say it, but I suspect you have a sticky injector. The good news for you is that, from what I understand, they're changing all 8 now. I missed that TSB by two weeks.http://www.dieselplace.com/forum/smileys/Cry.gif


If it sticks open, I'd kill the motor ASAP, or ...


run it til it dies.


BTW, mine threw no codes when the injector went.


Rick





Your situation from the previous thread is what came to mind when this happened ...


I didn't notice any smoke, only because I didn't look - I was on the freeway and the noise/power loss happened very abruptly, and went away just as quick - it was just like the truck was running out of fuel or something - CLACKCLACK ... no power ... etc... The symptom leads me to believe this is not a normal thing, as I know I've gone faster than this & never experienced anything like this - VERY LOUD. I thought something was falling off the truck.


My problem is, it went away for the rest of the trip home. If I bring it to the dealer, of course Murphy will cause everything to work perfectly... I've got another decent freeway run today - we'll see what happens.


P.S., how has your rig been running since they replaced the injector? Is the injector design different than before, or do they simply install a new injector of the same type?

The truck has been running great. I decided to stop worrying about it (if it goes, it goes), but I'll be ponying up for an extended warranty that hopefully gets me to 150K.


I think they replaced the faulty one with the same injector design, but I don't know for sure.


If it goes again, it'll be eight new ones. I almost hope it does it before warranty expires.


Rick

UPDATE:

I did a 30+ mile freeway run today, plus around 15 miles of city driving - ran perfectly

??

Guess injectors can stick & ... heal themselves?

Like Rick said, I'm not going to worry about it - if it goes it goes....

...hopefully before the warranty expires.

<font size="1">the wonders of technology... how did my dad get his '82 honda to last over 370,000 miles AND still going strong?</font>

That loud clacking noise and loss of power is exactly what my truck did when the #1 injector stuck open. Did you notice a lot of smoke out the tailpipe?


I hate to say it, but I suspect you have a sticky injector. The good news for you is that, from what I understand, they're changing all 8 now. I missed that TSB by two weeks.http://www.dieselplace.com/forum/smileys/Cry.gif


If it sticks open, I'd kill the motor ASAP, or ...


run it til it dies.


BTW, mine threw no codes when the injector went.


Rick





Where can I find information on that TSB? I'm going to bring mine in to be looked at as it did it again on the freeway &amp; I'll like to be armed with the bulliten knowledge...

Inte do u have the new LLY motor or the older LB7 ?

Inte do u have the new LLY motor or the older LB7 ?


New LLY - just ordered the truck in Jan or Feb &amp; picked it up the end of March.

one more update ... and maybe a question.


I was driving to a job today - did about 30 miles of 60-70 mph freeway, stopped for an hour, then back on the freeway. Within the first 10 miles ... CLACKCLACK, billows of smoke, power loss ... bad stuff in general. Lasted a few seconds, then went away. Happened AGAIN a few miles later - same thing, few seconds, then gone. I had no choice but to drive through it - vary the throttle &amp; it seemed to go away for a while.


Fortunately, I made it to my destination &amp; finished the job, BUT, when I made the ~40 mile freeway trip home tonight, it ran perfect.


My problem is, I'm obviously aware that the injector(s) are shot/soon going to be. I can't afford to have the truck dump me when I'm on the way to a job. Is the dealer going to fight me on getting them replaced if the symptom isn't occuring when the truck is physically at the dealer?


I took notes each time the symptom occurred (pad of paper &amp; pencil in the center console). The truck has less than 2500 miles on it &amp; one (or more) of the injectors have stuck on FOUR separate occaisions now - I have the milage, approx speed &amp; rpm at the time of each occurance.


Suggestions on how to present this to the dealer...? I'm dropping it off tomorrow for an appointment scheduled for Monday.

Now THIS is a drag...


Last Saturday the injectors acted up again in a big way twice in 9 miles of freeway driving. I then drove the truck 91 miles to the dealer to drop it off &amp; it ran fine for those 91 miles.


I'm now told that the truck has to fail while it's at the dealer or they can't replace the injectors. One of the techs is going to drive the truck home to try &amp; get it to act up. Problem is it will run fine for 500 miles, then fail several times within 10 or 20 miles.


So I guess I'm now paying for someone else to drive a $45,000 rental car in the hopes that I can get it fixed!?


http://www.dieselplace.com/forum/smileys/Angry.gifno like.

I had this exact thing happen to me. When I heard the noise I saw lots of smoke out the exhaust. This happened several times during the next several hundred miles. I had to make another trip to Ocala and filled up at the same place. It did it several more times. I didn't know what to think, I only had 500 miles on the truck. Now I know that it was bad fuel. Never had the problem since and no damage was done.


Kirk

sounds like an injector issue.is it lly or lb7.

sounds like an injector issue.is it lly or lb7.


Apparently it WAS an injector issue. The truck has been at the dealer for exactly 1 week now &amp; one of the techs stuck some diagnostic stuff on it &amp; used it as his personal vehicle - sure enought it freaked out on him going to work one day &amp; they traced the problem to the #3 injector. Parts should arrive Monday.


Odd thing is, I just got this truck in March - it's an LLY with the new external injectors that aren't supposed to have these problems...


Hopefully it's just a fluke.

I hate to say it, but I suspect you have a sticky injector. The good news for you is that, from what I understand, they're changing all 8 now. I missed that TSB by two weeks.http://www.dieselplace.com/forum/smileys/Cry.gif


Rick





Rick - mine had the same problem. Massive amounts of smoke, etc... the #3 injector was apparently the culprit.


I've since learned the TSB to replace all 8 injectors only applies to the LB7 engine - not the LLY. With the new style injectors, they only replace the problem unit. Possibly by virtue of the external design.


...now that I think about it - these new injectors aren't supposed to have these problems, yet mine obviously did. I wonder if the new "external" design wasn't so much an injector improvement as much as a design change to make replacing faulty units easier...?


Creepy thought.