Well, hoping stuff gets better doesn't work, need to get serious about getting truck running right. Please review sig. for truck details and please ask for more if needed.
Truck runs pretty darn good when not pulling and starts quick and easy, idles smooth. But hook up to anything and pulling power goes way down, pull 2k and it's noticeable. Pulling 6500# boat/trailer and really struggled, oil consumption at that time went up to 1 quart in 1300-1400 miles and fuel economy went down to about 12 mpg (should be at 15-16), running 2000-2100 rpm (63-65 mph). IP was recently rebuilt but not confident of rebuild as fuel pressure snubber was opened all the way (replaced gauge, thanks butthead) and timing was set at 12 instead of 16 which was corrected by a much more competent shop. No, I will not trust the first shop with my truck ever again, and I did go back after the rebuild did not do anything at all, the shop had me drive while their "mechanic" sat in the passenger seat. I will be getting back into Enterprise's area with a trailer in couple weeks, but would like some ideas before I can get to them, sure wish I lived next door.
Doing a compression check tomorrow depending on how bad hangover is, gauge/adapters on order from NAPA. Fuel pressure is within specs. (got Airdog). Boost runs 8-15# sometimes hitting 20, EGT runs 675-950, trans. temp runs 125-150, this while pulling 6500#. I do believe all the easy,obvious items have been checked and/or corrected but please ask about 'em anyway. I really need ideas, truck is commercial vehicle and is my living, and it's not able to pull worth a damn right now. Just want to find the problem as that would be a great relief even if I need another engine, at least I can make a plan for repairs then. Coming to ya' all with hat in hand, thanks guys. Sorry, I don't always put things in prpoer order. One more thing, not using cruise, all by foot to run down grade to make it up next grade easier, so upgrades run 50-55mph, grades are down south along I10 Texas so ya know those are quite mild grades. And the wastegate is no longer blocked.

 

i would start with a compression check. if your burning that much oil something may not be right. how many miles are on the bottom end?

 

Thanks for the reply, compression test is on list of stuff for tomorrow. Truck is just broke in at 325,000 miles. This problem seemed to happen quickly, of course quickly to me is about 10,000 miles but I fought pulling power issue for 80k or so, lot of shops looked but none could figure it out. Dang it, I got a mechanical for ease of diagnostics.

 

What are your exhaust temps reading when pulling a grade loaded? I'm going to stay away from saying a compression problem because it's not using huge amount of oil. It should pull hard regardless. How big are your injectors? Where is your plate set at? How is the AFC tuned? Are you still running a 180hp pump? When you notice the power loss how does coolant temp look? Does the engine feel like it's slowing down or does it feel like the transmission maybe slipping. I see you have a good tranny but just trying to cover some bases.

 

Egt's pulling very moderate grade hit 950-975 and I keep my foot very light and run at the grade, I know that does not seem too high but it would pull 15k across Rockies easier and run 800-1000 degrees pulling 6-8 mile 6% grades at 55-60 mph. Injectors are 5 hole, not 100% marines, I'll have to dig up the design by Red Oak Diesel. Plate is 1/16-1/8 from full forward. Afc is about 80% forward, spring is not lose but just tight enough so it doesn't flop around. From a dead stop putting foot down but not to floor, it will belch a medium size cloud of smoke then clear up and take off real good, rolling down road put foot down it will roll smoke till you let up or get a ticket. I don't play with it much, (it's a work truck) that is just to get around traffic or to see what it's running like. AFC tuned just about right I believe, but not the first time I've screwed up. Still running 180 hp pump. Coolant temp according to dash gauge and in 70 ambient air temp with 6500# or so trailer runs around 185-190, in 100-110 ambient air temp coolant has hit 210-220 with a/c off to help keep temps down, that really was not enjoyable. Does not feel like trans slipping more like engine wants to slow unless you put foot in it and egt's go up (of course), engine has feel of real struggle to keep same speed even on level ground, at times feels like working even harder. This is while pulling, empty it runs pretty darn good. Pulls 6000#-7000# harder than it used to pull 15000#. Throw any ideas/diagnostics, more questions at me, thanks and have a good evening

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By the way 12valvetater, how's the cam your running working out for you. Curious for my future needs.

 

How about filters? Have you cleaned/installed fresh fuel and air filters? Have you changed tire size? What size tires are you running? Are they fully inflated? Have you changed brakes recently? Might want to take a look at them and make sure they aren't dragging. It sounds like you have a pretty well tuned truck from the sounds of it. Have you noticed a drop in mileage?

To be honest with you I really don't know how I like the cam. I installed it when I rebuilt the engine and I changed so many things that I can't really give you a good answer on what I gained from it. When I put this cam in I didn't to uch about cam profiles and wish I would of. I don't know what the specs are on it, although I am going to ask Lamar the next time I talk to him. I may even swap it out for a Hamilton Big Stick as I have heard only good things about them. At the least I will be taking it out and having it drilled and tapped as mine is not the gear is just pressed on and it scares me now that I know what can happen.

 

Clean air and fuel filters, changing to 10 micron (carry 2 and 10 with me, gotta have spare filters with ya). Tire size is 235/85/16, same as always run, front at 80 psi rear at 70 psi. Front and rear brakes good, carry thermo temp gun with me to check various temps, that and I like having more tools. Yes to drop in fuel economy, more than seasonally adjusted for crappy fuel. 15k boat on gn have run 14 mpg coast to coast, empty 18.1 now (foot working and trying for best fuel economy) versus average 19.8 empty on crap fuel. Thanks again for replying, this ain't bad for me havin' 'bout 8 shots of tequila, gimme another hour. One great thing 'bout my own operating authority is I make my own time, no money but lotsa time. yield=yes I estimate lotsa damage

 

i just changed my buddies turbo. his kinda did the same thing. it was running ok then later he stopped and fueled up and when he left it didnt have power. we pulled the intercooler line at the turbo and it wouldnt even whistle. we threw a turbo on it and it ran like new again.

 

But he says it runs good unloaded a turbo would make it have less power regarless.

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I thought about t today and was thinking maybe the diaphragm in the AFC may have a small tear or pin hole in it. It runs good unloaded, but when you work the engine harder the increase in boost opens this hole and doesn't allow the diaphragm to work quite right one the foot.

 

mabey have the injectors pop tested,

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to see if you have a problem with the afc pull the foot out and see if the problem goes away, you will have to feater foot it when you drive