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Boost Drop?

1K views 4 replies 3 participants last post by  Lilpooh 
#1 ·
This is my first thread, and i wanted to take a second and say thank you for having me, and I'm excited to be part of the team:icon_ford:

I am currently having a Boost drop/fall off problem and any insight or advice would greatly be appreciated. This is what i do know thus far:

2005 F-350 6.0 52,000 miles, Stock. FICM re-flashed by dealer for contribution
recently purchased truck, approx 10 weeks ago

A few weeks ago i noticed that i wasn't building consistent boost. The truck started to only spool to 10psi, and then if i hit it and went WOT the boost would drop down to 2-5 psi, and then at other times the truck would be okay, spooling a consistent 18-25ish lbs depending on throttle demand/incline and shift demands

My initial check out:
Maint: Oil change, replaced oil filter
-changed both fuel filters and check air cleaner
-I pulled the EGR valve, very clean
-pulled charge boots and inspected for breaches in hose
-pulled turbo, split primary half, cleaned vanes (emory cloth on all moving VGT parts)
-Inspected VGT solenoid o-rings

Truck isnt throwing a CEL or Any diagnostic error codes
FICM is solid at 48-48.5 volts
Engine oil temp and Coolant temp delta is steady at 5-8 degrees

I plan on doing some work to the truck in the next month or so.
-EGR delete
-5' turbo back
-intake
-programmer

Any advice would be greatly appreciated. This is what im thinking it might be
-defective VGT solenoid (from my reading this is an uncommon repair at 50k)
-Leaking gasket on compression side of turbo
-EGR valve not seating properly??:dunno:

The symptoms of this boost drop somewhat seem to correlate to engine temperature. the Truck seems to run great after about 30 mins of driving
 
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#3 ·
A restricted air intake can cause loss of boost. If it's really clogged with sand for example, it can even cause turbo seal failure. This happened to me after running the truck hard in sand.. my air filter became clogged which caused other more serious failures.

Have you inspected your air filter lately?

*edit* see you already checked the filter... if it's been run in dusty/sandy environment or exposed to water it would be wise to replace it.
 
#5 ·
If it's a early 05, it might have the late 04 engine. Do you have a one piece intake elbow or a two piece with the EGR butterfly throttle body? Sometimes the throttle body valve gets sooted up and sticks, and sometimes the actuator for the valve fails.

Did you check the VGT wires/plug/pins in plug for damage?

Might also be the EBP sensor and/or tubing is sooted up. Also check the EBP wire harness and plug.


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