Engine/Transmission (1998.5 - 2002) Fwup-Fwup-Fwup noise

[FJfonda]

I recently have been towing in the 10-12,000 lb range and have noticed a noise that I have not heard before. As I approach a uphill in full boost, full throttle, 5th gear 1800-1900 rpm, then downshift to 4th and apply full throttle, I immediately get a FWUP-FWUP-FWUP noise, (at 3-4 FWUP's per second) and this will continue until I let off then gently roll back into the throttle. There doesn't seem to be a reduction in performance and all gages, including boost, look normal during the "noise event". I check the post turbo hose clamps every oil change so I'm pretty sure this is not a loose clamp..... any ideas??

 

[RustyJC]

Do you still have the stock airbox? Is the inlet sleeve leading from the fender well to the airbox still in place?



Rusty

 

[FJfonda]

Hmm

Rusty,



Yes and Yes...



I have a stock air box with a K&N. The sleve is in place but not attached to the fenderwell... do you think that could be the noise?

 

[RustyJC]

That's what others have reported. You might try pulling the sleeve out and see what happens. It's not going to hurt anything to try since the sleeve isn't connected to the fenderwell right now anyway. You might also take a look at this thread as this is another fairly common noise that shows up under the same conditions.



Rusty

 

[OL RATLR]

noise

That is probably it. It is called Turbo bark most all of your bigger air cleaners

like AFE+ Scotty II does this on fast deceleration caused by a lot of air rushing in to the Turbo. Hope this helps.

 

[RustyJC]

Actually, turbo "bark" or surge generally happens on deceleration, not on acceleration. This noise may well be related to unstable or turbulent flow into the turbocharger, but it doesn't fit the typical profile for turbocharger compressor surge. If it's going to do it, the turbo will generally surge when you get off the smoke pedal too quickly, not when you're under WOT conditions.



Rusty

 

[FJfonda]

OK.. gotta try

OK... thanks for the info. I did the gurgle-heater-hose-nipple-fix early on and this noise is quite different. I'll pull the inlet sleeve out of the airbox for the tow this weekend and let you know the results.

 

[Texas Diesel]

Mine does it with stock filter, K&N, and the BHAF II. Now I just ignor it like DC does the LP problem :-laf

 

[merryman]

I had a noise that may be the same---it came under the same circumstances. Occasionally it would occure under steady, fairly hard pulling in 5th gear, but mostly just as I would down shift to forth.



It did not change with removing the sleave between the air box and the fender. It did not change when I went to a K & N Cone filter.

Then relying on a post (about two years ago, I believe by Bill Stokard (sp), I moved the heater hose connection from about midway or further back on the head to an available port near the front of the head----no more noise.

There was a supporting theory on why/how, but I do not recall it.

He got the "cure" from Carson City Dodge when there for a May Madness event as I recall.

Vaughn

 

[Chief USA]

By chance... ... ... is this what you are talking about?



Hard To Diagnose Noise Coming From The Engine Turbocharger Area TSB 09-04-99



I agree with merryman and his theory.

 

[FJfonda]

I had performed the TSB referenced by rfrazier but this noise is different. The TSB does not include moving the hose connection. I will try this next if the sleeve removal has the same results. Hmmmmm... . probably would be a good time to change antifreeze as well.

 

[Chief USA]

I may have my TSB's and fixes mixed up, (wouldn't be the 1st time) but I thought I remembered reading about a procedure changing to a different part # thermostat to address this problem as well. I will have to look a little more.