For background I have an 07 f250 SCLB XLT FX4. In 2018 I re-bulletproofed my truck when I found diesel in my coolant.
I purchased river city diesel 175/30 injectors, kill devil diesel heads, and a powermax with a billet wheel that I changed the compressor housing to a gt40.
all was great for a few months until my exhaust whistle slowly started disappearing. Over the years my truck has continuously lost power. All the Pids on my HPtuners scans and sct logs are normal. I have changed exhaust gaskets and rebuilt my turbo numerous times thinking there was an exhaust leak.
it feels like a high pressure oil leak except my ICP shows normal pressure.

i have finallly had enough and I pulled the injectors out and started to tear them down. The high pressure oil ball connector o ring looks perfectly normal, the copper washer is fine and sealing well. All o rings on the external side of the injector look good.
river city diesel places a one time use nut on the spool valve bolt so I went ahead and broke every bolt that revealed my problem. The o ring on the under side of the spool valve body was completely deteriorated on 7 of 8 injectors.

even though my scans show good high pressure oil my injector would not see high pressure oil because of that failure. They’re being rebuilt now to be placed back in the truck.

the purpose of this post is because I have searched for years since something hasn’t felt right and I have never found information on line that matched my symptoms.

my symptoms were a normal idling and starting truck that had a little bit of haze at idle and smelled rich.
when I got to about 2400 rpm’s the engine felt as if it was starving of fuel even though it would still be smoking a touch. My fuel pressure maintains steady with the regulated return I built and idles at 62psi.
i want anyone else to know of a possible solution if they are having the same symptoms as me.
accurate diesel makes an internal o ring and external o ring kit for less than $100 to service injectors if you run into the same issue.

 

good info and post. Did you get the truck back up and running after the o ring swap? How's it run?

 

it runs great now, like the day I first installed all of the goodies. I really wanted everyone to know about the o ring failure under the spool valve body as I have never seen a post about it. I have scoured the internet for years looking for my exact symptoms.
I have my whistle back again finally too.

 

That's excellent. Thanks for signing up to the forum to share the symptoms, your troubles, and the remedy.