Help Needed Really strange noise

[davemac]

2001 F250 7.3L 160k miles Supertune "Heavy Hauling" code loaded.

Recently I have developed a really strange loud squalling noise from under the hood when I get hard into the throttle. Starts at about 2250 RPM. No detectable loss of performance. Seems to come from the area of the turbo or nearby. Hard to tell. Stops when I back down on the throttle.

The noise seems to be too low in frequency to be the turbo itself. Coming off idle I can hear the turbo spool up with it's usual high frequency sound.

Good Ford diesel mechanic friend says he has never heard anything like it!

Does anybody have any insight?

Thanks

 

[JRJ04]

do you have an upgraded intake or exhaust? sounds to me like you may be experiencing turbo surge, where there is too much air trying to be drawn in by the turbo (due to tuner, load, etc) but the compressor wheel cant move it, and as a result, you get some chatter.

the fix is to replace the compressor wheel with an aftermarket one that will flow more air and keep up with the demand.

 

[BIG JOE]

First Off.. Welcome to SDD

Second, I go with JR on what yer hearing. Turbo stall/surge.

The compressor wheel is essentially.. Cavitating... due to the lack of laminar intake & exhaust, air movement

Joe

 

[davemac]

Thanks for the welcome! Been here before but it has been so long the system forgot me.

Your explanations sound plausible, but why did it appear suddenly? No mods in the last five years. Have a turbo back 4" stainless dual exhaust and a KN drop in air filter which it occurs to me I have not cleaned lately. Hmmm Have not seen a filter obstructed light but not sure if that switch really works.

Will check filter tonite. Meanwhile keep the ideas coming.

davemac

 

[JRJ04]

Thanks for the welcome! Been here before but it has been so long the system forgot me.

Your explanations sound plausible, but why did it appear suddenly? No mods in the last five years. Have a turbo back 4" stainless dual exhaust and a KN drop in air filter which it occurs to me I have not cleaned lately. Hmmm Have not seen a filter obstructed light but not sure if that switch really works.

Will check filter tonite. Meanwhile keep the ideas coming.

davemac

Honestly, that drop in K&N is about the worst thing you could put on your truck. They have been known to not seal correctly and can suck dirt. In your case, my guess is, the thing is so dirty that it cant pull the air the turbo is demanding. You could try cleaning it, but i would really go back to stock until you upgrade to a different air intake.

The DIY intake is always and option as well...

 

[Smoky]

davemac, first of all The loud squealling noise could be the bearings on the belt idler going bad.

I just about 2 hours from you in Waynesboro. Fill out your signature so we know what all you have and what you've done to it.

 

[rammertide07]

Just to touch on what others have said...

Take your belt off and spin all the pulleys and look for metal dust behind the pulleys. If one/some dont spin freely...replace the bearings.

I also had a turbo to go out last year. Made a similar noise as to what you described. 300mi later and it was sucking up oil and blowing clouds of white smoke out of the exhaust. I parked next to a building, and when I turned the truck off...I could hear the bearings in the turbo grinding (sound bouncing off the building I was parked to). 2 days and $1500 later...back on the road

 

[davemac]

Ok, Thanks for the replies so far.

Per suggestion I replaced KN drop in with standard paper filter. No help.

Still have the Supertune heavy haul code in the computer. No changes made to vehicle since long before this started happening.

As I mentioned, this noise only occurs during HARD acceleration. At about 22 to 2500 RPM. Does not happen at any speed under more normal acceleration.

I am familiar with the sounds of bad idler, alternator, water pump, etc bearings and this is not what I am hearing. For lack of a better way to describe it, it sounds like a child's plastic horn and it is LOUD.

The idea of bad turbo bearings has merit. However, when in a position to hear the turbo spool up from idle it sounds perfectly normal. I stop at a security checkpoint several times a day. Window open, next to a concrete barrier where I can hear the turbo sound echo off the barrier. Low level, high pitched accelerating sound, nothing like what I have described.

Anybody ever rebuild a turbo? Rebuild kits are a lot less expensive than a replacement turbo! What is a "diy intake"!

Keep the ideas coming! Thanks!

davemac

 

[BIG JOE]

Do you have the stock, 99+ compressor wheel ? How 'bout gauges ?

DIY Intake: alota SDD members have Fab'd up their own "Open Air" Intake & Filter set ups, useing a conical filter, for more air CFM.

You might take the turbo inlet horn off.. and inspect the leading edges of the turbo vanes, checking for any chipped or deformed vanes... and also check for any end play or lateral movement... Push & pull the wheel while turning it.. if theres any drag... there's yer sign(s).

What condition are the I/C charge tube boots in... Maybe yer hearing that horn sound.. at high boost pressures.. from a leaking/cracked boot ?

Joe

 

[davemac]

Thanks, Big Joe

Stock turbo wheel. No gauges. Maybe someday..... ($$)

Charge tubes are a possibility. Will pull them and check for cracks. Take a look at the turbo wheel at the same time.

Will keep you posted. May be a day or two.

Anyplace to go look at the "diy intake"?

davemac