Engine/Transmission (1998.5 - 2002) Noise from the turbo / air box area

[RSens]

Hi Folks: I'm having a noise coming from my turbo / air box area when under heavy throttle going up a steep grade. I have read in the forum of people having a woofing noise when letting off the throttle quickly (turbo surging) but my issue is when pulling real heavy. I have a '02 HO - 6 speed and it usually happens when in 5 th gear pulling real heavy. Can you people give me a hint at what I may look for to stop this noise. Is the air filter not letting enough air pass through it (filter has been changed)?? Suggestion please.

 

[csevers]

Check for the tube between the square air box and the fender if it is out of place there can be more noise than normal. The filter minder can give you a hint if the air filter is pluged or if there is a restriction. What does the noise sound like? Whistle or rushing air or drone? Check to see if the cover on the aire box is on correctly. Hope you find and fix the noise.



Craig

 

[DwayneKelch]

RSens,



I've experienced the same noise (sounds like driving on a flat tire), in the same location, under the same conditions. Happened on both my 98. 5 and 2001. I back out of the throttle, from 20 pounds of boost to 17, and the noise goes away.



So, what's up with this... ?

 

[RustyJC]

Mine has always done it, both with the stock airbox and (to a lesser extent) with the BHAF when towing our 36' 13,500 lb 5th wheel on the uphills. I'm convinced it's inlet air turbulence at the turbocharger due to the curved air inlet tube - design convention says that you need 5 pipe diameters of straight pipe at the turbo inlet or, alternatively, properly designed turning vanes to ensure that the turbo impeller isn't trying to compress turbulent airflow.



JM2CW



Rusty

 

[RSens]

I was wandering if it was developing too much boost pressure when under full throttle. I checked the air inlet tube and there is no restriction up to the filter. The filter minder is at 0. I currently don't have guages so don't know what the boost pressure is when it makes the noise. Thanks for the suggestions on what to look for.

 

[RustyJC]

Mine did it at 22 psig boost (stock), 30 psig boost (EZ with stock injectors) and 34 psig boost (EZ with DD2's). I think it's flow related, not pressure related.



Again, JM2CW



Rusty

 

[lcoblentz]

I posted a similar question back a while. I never have found the answer. It seems to appear when it want to (always under acceleration), and also seems somewhat heat related. i. e. , when the engine is warm from pulling a grade. Mine is always the most noticeable when accelerating from a stop.



It's a very sounding noise. After checking torque on all exhaust manifold bolts, removing the little tube between the air and fender, changing air filter, and changing the thermostat, I have decided to quit worrying about it. All gauge readings remain normal, and other than the awful sound, nothing "feels" different when it happens.



Still hoping someone figures this one out someday!



Larry

 

[pmartin]

My 2002 3500 HO 6-speed has done this since new. Usually happens after I shift from 6th to 5th on a steep grade and after I again put the pedal to the metal (not while shifting gears). It is a "flutter" like tread has come off right front tire. I can back off the throttle a little and it will quit. Mechanic told me it might be the plastic horn from air cleaner intake going forward into fender. He suggested I remove the plastic horn to see if that stops the noise. May try that in the future but haven't yet because it would probably let more warm under hood air into air cleaner intake rather than cool outside air??? Hope someone has answer.

 

[DwayneKelch]

pmartin,



Can validate it's not the horn from the air filter box to the fender, mine is gone... see profile. I like how you describe the noise though... I hear the same thing.



The noise I'm hearing starts under the same conditions as you and Icoblentz described. Although, I've never experienced that sound from a dead stop, usually up a steep grade, at max boost.



I've tightened and checked everything I can think of... no harm, no foul.



If it's as RustyJC stated, might the TAG prevent this condition?





Dwayne

 

[Car_nut57]

RSens,



The condition you describe can be caused by a few different things such as Turbo Stall, waste gate, turbulent intake air etc. First of all the noise you hear when shifting is the turbo changing speed and can be some air coming backwards out of the turbo. In extreme cases this is often called barking the turbo.



Turbo stall happens under a heavy load and can happen at different boost pressures on different trucks. Turbo stall is usually a low cycle whooo-whooo-whooo noise and in extreme case you will actually see the boost gauge start to fluctuate or feel the truck surge. Usually if this condition is caused by turbo stall, if you floor the truck the sound will stop. the sound is made by the turbo slowing down and speeding up because of the pressures present on each side of the turbo. Turbo stall on a Cummins is very unlikely unless the truck is highly modified.



Another possibility is the waste gate unseating. If this is caused by the waste gate, typically the frequency will be much faster than stall and a harsher sound, some times call waste gate flutter. This is easly solved my tightening the tension on the waste gate with a stronger actuator or making adjustments to the stock one.



If the problem is related to turbulent air at high speed entering the turbo the Turbo Air Guide (TAG) or other means of altering the air flow should make a difference.



If the noise is constant under heavy load conditions it could be a leaking exhaust manifold.



Hopefully this gives you a few things to look at.

 

[CumminsDZL]

My truck did the same exact thing. when i switched from stock box to the BHAF no more noise. i would check the plastic peice from the box to the fenderwell. its like it is collapsing or shaking. just take the sucker out and see what happens.

 

[pmartin]

to car_nut 57,



thanks for info. My "flutter" noise is during a hard pull as rpm builds above about 2200. Backing off throttle slightly will stop the noise. Is it not caused by shifting. The flutter will develop when you down shift and again put the pedal to the metal (not immediately but as rpm increases). In Chandler there is a railroad crossing followed immediately by steep hill. I can shift down to 3rd or 4th to cross the rough tracks then apply throttle without shifting and the flutter will start as rpm increases in the same gear. Does this give you any better clue as to the problem? I really think it is an air flow restriction, not a turbo pressure problem.



Thanks

 

[Car_nut57]

pmartin,



Very difficult to say. Is the flutter fairly rapid? If so some times a loose clamp on an intercooler boot can let air escape making a noise like that. Turbo stall is usually a slow frequency fluttery air sound and is not common for the Holset turbos used by Cummins so I would eliminate this as a possible cause at this time unless a manifold leak is causing exhaust pressure to escape before the turbo. Good luck finding the problem.

 

[RustyJC]

As I mentioned on the related thread in the Towing forum and in a prior post on this thread, this is not an uncommon noise on the ETH/DEE's in towing applications. Mine did it stock, with the BHAF, at 22 PSIG boost, at 30 PSIG boost (stock injectors & EZ) and now at 33-34 PSIG boost (DD2's & EZ).



I've just about convinced myself that's it's due to turbulent flow at the turbocharger compressor inlet caused by the curved air inlet duct. Industrial engine design convention requires a minimum of 5 diameters of straight pipe (e. g. , 100" of 20" diameter pipe) going into the turbocharger, unless turning vanes or other flow-straightening devices are used. The existing inlet air duct obviously doesn't conform to this convention.



That's why I'm curious if anyone whose truck manifests this quirk has installed a TAG, and if so, what (if any) changes has it made in this noise phenomenon?



Rusty

 

[Car_nut57]

RustyJC,



At the risk of sounding like a salesman, maybe you should get a TAG and try it and let us know if it helps with this issue. Many have reported the TAG making the turbo quieter, but I am not sure what type of noise they are referring to.

 

[DwayneKelch]

All,



I've been keeping up with the posts to this thread as I'm very interested in solving/eliminating this flutter noise too. Have experienced this on the two CTDs that I've owned, under the conditions mentioned.



I have considered buying the TAG since reading about it on the TDR site. Think I'll purchase, install, and inform. I do a lot of towing (around 7K pounds) through the Rockies and will be able to provide outcome.



Now, where's the best place to get this jewel?





Dwayne

 

[Car_nut57]

DwayneKelch,



We are the inventor and manufacturer of the Turbo Air Guide (TAG). I would really like to hear how the TAG effects the issue discussed in this thread. So give me a call and we will get you fixed up with a TAG and look forward to hearing about your results.

 

[DwayneKelch]

Car_nut57,



Oops, sorry I missed your sig. Sounds like something I need to try, especially at the altitude I live. Hopefully, the TAG will provide more/better air flow to get back some of the hp I've lost, and eliminate the annoying flutter noise.



Are you open on Saturday? If so, expect a call in the AM. Thanks.





Dwayne

 

[DwayneKelch]

UPDATE:



Well, I received and installed the TAG... thanks, Dave.



I installed the jewel just before heading off to hunt ducks, with a 4K pound trailer in tow. It feels like I have faster, smoother acceleration than before (towing same trailer/weight). Fuel mileage, w/winter fuel, was a little better (15. 1 mpg). Too, it appears I have less black smoke out the tail pipe when accelerating from a stop and shifting between gears.



Today was the first day I've driven without a load behind the truck, performance does feel different. It's hard to explain, but the engine accelerates smoother. Will run a tank of fuel through the engine, calculate mileage and post again.



I stayed south and east of Colorado Springs and didn't get challenged by any steep grades, so don't know how it will impact waste gate flutter. Although I did peak and hold boost (20 psi) before shifting and didn't hear flutter (didn't before under same conditions). Will plan a trip to test that too. 'til then.





Dwayne

 

[RustyJC]

Dwayne,



I for one look forward to hearing about your real-world results.



Rusty