2005 Excursion lacks power intermittently 288,000 miles

LeRoy · May 2

At a warm steady cruise @35mph under hard accell - WOT - the engine will rev to 3000rpm and hang there boost drops to 0psi until lift off the pedal - WOT the boost comes up and accells normal 3500 rpm and upshifts - This happens after warmup - runs normal cold - tried a Boost pressure sensor- Fuel press is 50psi at wot - EBP 37psi wot - ICP goes to 2850psi wot even at the failure - loosened exhaust at turbo - no difference - replaced turbo assy - same results - HPOP new - was loosing / dropping pressure on accell last month - would build to 1700 drop to 400 @ wot

Outta ideas ?

I retired working on these things and my former dealership is asking for help - I may have forgotten a few things but not the 6.0's

I'm open to anything - Thanks in advance

KHFord · May 3

I had one similar to this about 2 years ago, it was a fire rescue unit, I had to do 3 turbos before I got a good one. I ended up cracking them open and the unison ring was warped in the first 2 reman replacement turbo's if I remember correctly. Sounds the same though, I remember having to get it fully warmed up before it would act up.

LeRoy · May 10

On the second reman turbo

I took it for a drive today to try a few different things

it appears that the Excursion has a throttle plate that has a bad position sensor and the plate would go shut while looking for the egr to operate and block off the intake

disconnect actuator and test drove way better

no air in - no boost - no power

mchan68 · May 15

On 5/10/2024 at 9:28 AM, LeRoy said:

On the second reman turbo

I took it for a drive today to try a few different things

it appears that the Excursion has a throttle plate that has a bad position sensor and the plate would go shut while looking for the egr to operate and block off the intake

disconnect actuator and test drove way better

no air in - no boost - no power

You have an early build 2005 Excursion with a 2004 model year engine then. Those EGR throttle plates could be problematic on the ones I recall playing around with. But usually a trouble code would set of there were any issues with them (P0487 if I recall correctly).