6.0l died and no start

[Bigmike1026]

Hi guys, im new to this site as a member, but ive been looking-over-the-shoulder, so to speak, for some time now. I just want to thank everyone who participates in these forums for their time and effort in helping others with issues and questions. Before becoming a member, this site has been an invaluable resource, and if i can be of any help to someone i'll be glad to lend a hand.

That being said, i have an issue. I couldn't find a thread that described it exactly so i'm gonna start from the top. If anyone has had a similar problem please share their experience in the interest of repairing in a timely fashion. This is something that i would normally drop off to have repaired by a trustworthy diesel mechanic, but i cant seem to get in touch with either of the 2 that i know. Therefore, i am going to attempt the diagnosis and repair myself. This is the first 6.0 that ive owned, but ive had upwards of 30 cars and trucks in the last 10 years, all of which ive fixed on my own for the most part.

For the last 4 months (about 10k miles) the truck has been running very rough. It almost felt like a low speed missfire. The most it would boost was about 15psi, with a light stream of black smoke coming out of the tailpipe that was visible in the sideview mirror at anything over half throttle. The truck would alternate between around 30% power to 60% power 2 or 3 times a day and had no CEL. Occasionally it would stall out completely and would be hard to start up directly afterward, idling on what felt like 5 or 6 cylinders at around 500 rpm. If you pressed the accellerator, it would spin up very slowly, maybe 3 seconds to get to 3000 rpm in park, without the boost gauge moving. Occasionally it would "snap out of it" and run perfect for 15 mins or so, but would eventually go back to bucking and hesitating with minimal power. I fooled with most of the common problems with these trucks along the way, but even though obvious problems would be located, fixing them never seemed to have a direct impact on the problem. Ive cleaned the coked egr valve twice, and finally replaced it once about 2 weeks ago; ive replaced the fuel filters 4 times this year, each time they were almost black and i was able to flush out about 2 handfulls of grated rust sand from the fuel pump housing and water seperator drain; ive tested the ficm voltage (good); and ive checked the air filter, chafing locations on harnesses and ductwork from the turbo. Ive used a mechanical fuel gauge on the test port by the filter housing (good), and ive load tested the batteries and given it a fresh oil change with rotella 15w40 every 4000 miles. This vechicle does absolutely no towing basically ever, except twice this summer to haul out my boat and put it back in the water.

Although these symptoms were annoying, they were tollerable. I use the vehicle for work as part of my small fleet (5 vehicles) and it was still able to go to jobsites daily, just slower than it normally would. Unfortunately, for the last week it has been having problems consistant with a high pressure oil problem, mainly hot starting. It is now at a point where it will only start ice cold (starts immediately though, runs flawless for almost 2 whole seconds) and then runs like it has a dead cylinder until it warms up completely and then stalls out and cannot be restarted until cool.

Any ideas?

[ruizhernandeztrust]

WOW!
You covered almost every aspect regarding the maintenance of the vehicle. oil, filters, electrical, etc... but you didn't mention when you cleaned the egr valve, you checked the interior of the intake manifold? how it looks? When intake manifold clogs the engine performance is poor. How about the turbo psi under load? getting 10-20 psi under moderate load should be normal.

[Bigmike1026]

Believe it or not, i have a small dustbuster that i use to suck out any debris thats loose from the intake. I usually get a small handfull when i shove it down the bore for 10 seconds or so. The most ive gotten the turbo to spool is 17-18 and thats floored on the highway, reaching its max speed of 72 mph.

[ruizhernandeztrust]

Originally Posted by Bigmike1026

Believe it or not, i have a small dustbuster that i use to suck out any debris thats loose from the intake. I usually get a small handfull when i shove it down the bore for 10 seconds or so. The most ive gotten the turbo to spool is 17-18 and thats floored on the highway, reaching its max speed of 72 mph.

17-18 psi under full load seems too little. I also have a 6.0L and when I floor it I easily get 25-33 psi under full load and my truck is 100% bone stock. I'm not a mechanic by any means but try check if the turbo is working properly or check if you have a boost leak somewhere. To me your truck looks and behaves like choked. Keep us informed.

Nelson

[chris1221]

have you run a cylinder contribution test? black smoke can sometimes mean one or more bad injectors, by bad i mean either stuck or possibly cracked at the tip, which lets too much fuel in. stiction symptoms usually improve a little when the truck warms up but a cracked or shot injector will just get worse, possibly even hydro-locking a cylinder...bad juju. im definatly not an expert but if the engine isnt firing right, i would think your turbo wont be allowed spool like it should and you definatly wont be getting top speed. hope this helps

[Cutting edge]

This is a FICM problem if i had to guess. All of the problems point to it.
Do the volt test.... And let us know.