I have an inconsistent, very scary noise coming from my engine. The noise sounds like metal scraping against metal and matches my RPMs. It rarely does it though, It kind of sounds like a bad pulley would sound. (All pulleys are brand new though) The only time I am able to hear it is if I step on the accelerator, and just let go of it after the RPMs reach above 3000 and then I hear the noise until the engine gets below 1000 RPMs. If I do it again right after I hear it, I wont hear it again. It only does it sometimes, but has raised a lot of concern for me. Is it rod knock? valve related? Driveline related?? Its really hard to tell where the noise is coming from.

The truck has 220,000 miles on it and I just got done rebuilding the engine. I went through the heads and had them port polished and a valve job done. The bottom end looked great so I left it alone. I have 180 injectors from RCD with their tunes. ITP fuel kit is installed. 4" MBRP exhuast. This noise happens in all 3 tunes of mine too, so I know its not just "1" tune related.

Any thoughts? Ever heard of this before?


--Snoop

 

It's a wild *** guess without actually hearing and seeing the truck but sounds like possible turbo problem to me. Did you go thru the turbo while it was apart?

 

What year is the engine and what mods have you done?

 

I also thought it was the Turbo but my buddy swears it is not. Yes, I took it apart during the rebuild and it showed some where, but nothing major. I personally think there is a problem with the Turbo, or a boost leak somewhere. I actually blew my boost gauge tube off a couple of days ago, perhaps because I was making too much boost?

Here is a complete list of mods:

ARP head studs
RCD head gaskets
RCD exhaust gaskets
Liberator Performance EGR Delete Kit
MBRP 3.5" downpipe with 4" back exhaust. Cat delete. Has MBRP mufller only.
Stock Air Intake setup
ITP Diesel Fuel Regulator Kit with fuel circulation fuel lines (from RCD)
Elite Diesel Coolant recirculation kit from thermostat to the back of each head.
Ported intake manifold
Gasket matched intake manifold
Port and polished exhaust manifolds
Gasket matched exhaust manifolds
Decked heads
Port and polished intake and exhaust ports on heads
Gasket matched intake and exhaust ports on heads
Stock valve size radii valve job with pocket porting.
Stock valve springs
RCD 180 mm Injectors
Amsoil Oil Circulation Filter Kit
Amsoil 5W-40 Full Synthetic Oil
Diesel Site Coolant Circulation Filter Kit
Autometer Gauges- EGT, Water Temp, Fuel Pressure, Oil Pressure, Oil Temp, Boost, Trans Temp
Most recent Ford Flash as of 1/29/2010
SCT Xcal 3 Programmer (from RCD).

 

Just need the MY or date engine made. Then the pros can help.

On your blown boot, brake cleaner on all parts and then light spray of hair spray on touching parts, should not come apart again.

 

Trouble codes always help....

Check your trans fluid to see if it's low or burned.

 

sounds like you need a fan belt. possibly a water pump pully and tensioner as well. This concern is most common after the engine reaches operating temps

 

The build date was 06/2004 No codes...

I have all new pulleys and a brand new belt except the AC and power steering pulleys weren't replaced.

 

Do you have an updated STC fitting on the HPOP? Mine made a noise that sounded a little different (more like metal bearings rattling around) but it had the same inconsistancy that you described. It ended up being the STC.

 

No, I wish I had a sensor there!

 

Do you think its the AC pump? When I got it re-charged after the build, they said there was a small leak somewhere. It has a new condensor. It blows cold, but takes forever to get cold.