Hello all, I am new to this site and will be posting on here frequently. I am currently a fleet mechanic for a loooonng line of ambulances with all ford diesels in them. From the 1988 era on up. Today i have one in thats acting up only when cold.
The info on the truck: 1998 E350 with a 7.3L Turbo. 100k miles. (who knows how many hours. I say this because most ambulances sit and idle all day in a parking lot) Completely stock.
symptoms- start the truck and it idles fine. Pull out of heated shop and hit the highway. Truck rolls black smoke and will only reach 15-20 mph. The after about 15 minutes of babying it it seems to free up and take off like it never happened and will run great the rest if the day. This only happens first thing in the morning when shes cold.
What i have done- Checked air filter and intake system in tact. That all looks good. removed turbo and inspected for signs of it sticking and it is free of dirt and spins freely. I hooked it up to my scanner and it says no codes are present, even in the continous memory.
Keep in mind that this motor sits in an ambulance and there is NO ROOM. Even popping the valve covers is going to involve some busted knuckles and a few swear words.

any help would be great!!!

 

im very hesistant to say this because i dont want you to go tearing into a turbo on just a hunch. so take this for what its worth. i dont know if those turbos have bearings or bushings, but i do know that continuous idling is not good for any turbo and will wear out the bearings or bushings. i had a similar problem on a dt466 in a pusher bus at the airport. once it got warmed up you couldnt tell there was anything wrong. like i said, JUST A THOUGHT. good luck

 

the EPBV may be sticking, it reads oil temp to close a valve in the exhaust imediately after the turbo to help with warm up.
there is a plug with 2 wires running to it under the turbo inlet, unplug it and see if it helps.