Does anyone else have a noise that sounds like a lifter knock when accelerating. I have an 05 LLY. Took it to dealer & they gave me some TSB's that covered this issue.My old LB7 did'nt make this noise. They said it was normal & would improve with more miles. I have a little over 1000 on it now.... Edited by: fishingn

Around 2500 ish RPM's? Then if so it is the Pilot Injection shutting off and yes it is normal.The LB7 did it also you may hear it better in a LLY . I have noticed that they are even quieter then earlier Duramax's. There is information here try a search.





Mac

I'll attest that you can really hear it in an LLY. Even with the 4" all the way back exhaust, you can hear the pilot injection shut off. Quite an abrupt change, but normal. Finally sounds like a diesel when it shuts off.


Dennis

My 04.5 lly sounds like that too and it's getting old http://www.dieselplace.com/forum/smileys/Angry.gif. I have almost 5000miles and it getting louder. Cant take it in till the work load slows down. HOPE that there will be a fix I love this truck.http://www.dieselplace.com/forum/smileys/Cool.gif O and mine is load at all times.Edited by: westwindsdiesel

http://www.dieselplace.com/forum/smileys/Thumbs Down.gif for 2004.5 lly

I had it below 10k, it got really annoying and in one day it stopped. I remember telling my wife and planning how we were going to take the truck in to the dealer, but on the way back the valve knock went away. It tried to come back around 8-10k but since then i have not heard it. It was audible accelerating, coasting, loaded or unloaded, at all rpms ranges but usually between 1500-2200 rpms.

I have exactly the same problem. Knock 1500-2000 rpm on higheay. Most noticeable at about 65mph. Only there under load. Ease off gas a little and it stops. Just posted a new topic on this. I took it to the dealer and they said the EGR control module was bad. Took them 3 days to get to that diagnosis after ruling out injectors. Sounds fishy to me. Said module was so new they would 'have to pull one off the line' and it would take about a week. They gave me a rental. Any tech's have anything to say about this. Not sure a problem with EGR would cause a knock.

There is a reflash for this in 05 I havent checked it out in 04 yet. Just did it on mine its a little better but still more noticable than the old lb7 was. john

Does anyone else have a noise that sounds like a lifter knock when accelerating. I have an 05 LLY. Took it to dealer & they gave me some TSB's that covered this issue.My old LB7 did'nt make this noise. They said it was normal & would improve with more miles. I have a little over 1000 on it now....

Hi, I have the same problm with mine. It sounds like it's throwing a rod. [EEK!!!!]

What TSB's cover this problem? Could you please post them?

Mucho Thanks.

Iam trying to post the bulletin the dealer gave me but the file is to big. How do i shrink it down.I scanned it & saved it to a file. It has to be less than 100KB.

Iam trying to post the bulletin the dealer gave me but the file is to big. How do i shrink it down.I scanned it & saved it to a file. It has to be less than 100KB.

I think if you try a C+P on just the text only, it might work.

Otherwise, could you please just post the TSB number[s], and we'll look it up here:

http://www-odi.nhtsa.dot.gov/cars/problems/tsb/

I'am getting the noise - sounds like a lifter - only when acellerating and mostly between 1500 - 2200 rpm - but what really bothers me is that there is no change in engine noise at any rpm!!! 1500-3200rpm the engine sounds the same - at no time can I here the split-pluse injection shut down. What gives? To my ears the engine sounds like stright injection at all rpm's. I keep running up the rpm's (1000-3000) and I have yet to hear that change "sounds like a diesel" in the engine.

This is what the dealer gave me. I copied it word for word from the document.





6.6L (LLY) Normal Engine Operating Characteristics-kw diesel DTC LB7 knock noise whine detonation rattle # PI01845A- (Mar 18, 2004)


Condition/Concern


A dealer may encounter a customer complaint of excessive noise on the new 6.6L (LLY) duramax diesel engine


Recommendations/Instructions


The 6.6L (LLY Duramax Diesel engine contains changes made for performance and emissions. The NEW 6.6L Duramax Diesel engine SHOULD NOT be compared to a 6.6L (LB7) duramax engine for a noise concern. The 6.6L (LLY) Duramax Diesel engine noises are most likely to be described as a knock or whine noise acceleration which are considered normal and do not effect the 6.6L (LLY) Duramax Diesel engine reliability and durability.


1. The 6.6L (LLY) Duramax Diesel engine knock noise on acceleration occurs during the transition from pilot to main injection that typically occurs near 2500RPM. This engine knock noise has always been an operating characteristic of the duramax diesel,but may be louder due to the new injector configuration to meet emission requirements.


2. The 6.6L (LLY) Duramax Diesel engine timing burst rattle at 1500-1800 RPM (light acceleration,light load fully warm). If determined to be excessive compared to a like 6.6L (LLY) duramax diesel engine. For diagnostic purposes advise using 1-2 tankfuls of a name brand/different source of diesel fuel to determine if the concern is caused by a fuel quality issue.


3. The 6.6L (LLY) Duramax Diesel engine whine noise can occur on acceleration or deceleration. The new Variable Vane Turbo is always adjusting its position for engine performance and emissions. This in turn may cause the 6.6L (LLY) Duramax Diesel engine turbo to be louder than the 6.6L (LB7) Duramax Diesel engine turbo. NOTE: IF CONDITIONS OF A 6.6L (LLY) DURAMAX DIESEL ENGINE KNOCK OR WHINE NOISE ARE ENCOUNTERED AND THE NOISE IS NOT EXCESSIVE COMARED TO A LIKE VEHICLE EQUIPPED WITH A 6.6L (LLY) DURAMAX DIESEL ENGINE. NO REPAIRS ATTEMPTS SHOULD BE MADE.