Intermittent Loss of Boost Going Up Hills - Diesel Forum

novimustang · 08-28-2009, 10:43 PM

I tow a decent size trailer, about 15,000lbs or so, and last week I was going through northern Maryland on I-68 (if anyone knows how bad those hills are...) and anyway one morning the truck seemed to have trouble getting up some of the bigger hills - when I would try to get it to downshift to keep the revs up, you'd hear the turbo just spool down like "uh thanks, but no." So, at least it felt and sounded like, I was all motor up those hills, which was tough and definitely made me worry about making it home. It only did it going up hills, and when I went to accelerate again on level road the turbo would spool up and I'd have power, but as soon as it got under load again the turbo tapped out. However, later that day, as well as the rest of the trip, the truck ran just fine like it always does.

The truck is an '03 6.0 auto, and it's bone stock. I do not have gauges, but could this maybe be just a temp thing? Although that doesn't seem to make sense because the morning I had trouble it was cool (~60s) and foggy, while later that day and the following day it was mid 80s (when the truck ran fine). So what are some things that could've caused a lack of boost under load? And only that one time, for a few hours. Again, for those that haven't driven it I-68E through Cumberland it is killer, but still I don't understand why this happened. Any thoughts?

**caryt** · 08-29-2009, 10:49 AM

Turbo vanes are probely sticking..if you had a boost guage you would see the needle fluttering. Sometimes it sets a code, the dealer can repair under warranty..I belive you can also DYI.

I hade the same problem..3 turbos later still have it a little but a SCT with Cales tunes got rid of 90% and runs much better.

BP6.0 · 08-29-2009, 11:17 AM

I was having the same issue towing and empty, my problem ended up being a cracked CAC boot( the upper boot). The crack was on the btm side of the boot so you could not see it. I would think I coud here an air leak.

novimustang · 08-29-2009, 12:37 PM

I read some other posts about sticking turbo vanes, and while I'm definitely no diesel or 6.0 expert, it seems kinda strange for them to stick in that type of situation totally randomly when it worked fine later that day and every other day I've had the truck. I also read some posts about the vanes getting stuck after a long downhill run or something, but for the turbo to consistently work - just not under load up hills - made me think it must be something in the computer or something that was seeing something it didn't like and was therefore not allowing it to boost up? I dunno, like I said I definitely am no expert, that was only my theory.

I did also think about the possibility of a boost leak somewhere, but again being that the issue only happened once for a period of 3-4 hours or so, it seems like a boost leak would be something that I would notice all the time? Like if it was a crack in the CAC boot or if the tube blew off or something I would think it would run like crap all the time.

Strokin' 6.0 · 08-29-2009, 12:44 PM

With the truck being an '03, unless he has the extended warranty, it's no longer under warranty. Follow this TSB...if anything, at least your turbo will be clean and you can eliminate that as the problem.

novimustang · 08-29-2009, 12:58 PM

That sounds like some good info in there, but man I dunno about removing the turbo... this thing is both my daily driver and allows me to eat so I hate the thought of tearing it apart. Maybe I'll just disconnect the intake tube and spray some brake clean into the turbo while it's running.

It does have some interesting info in that TSB though, regarding EGR. Maybe I should just do an EGR delete anyway. Which, although I've been trying to find instructions online to determine if it's something I want to tackle or not, I'm sure that takes the turbo off anyway. Two birds with one stone maybe.

Strokin' 6.0 · 08-29-2009, 01:10 PM

Quote:

Originally Posted by novimustang

That sounds like some good info in there, but man I dunno about removing the turbo... this thing is both my daily driver and allows me to eat so I hate the thought of tearing it apart. Maybe I'll just disconnect the intake tube and spray some brake clean into the turbo while it's running.

It does have some interesting info in that TSB though, regarding EGR. Maybe I should just do an EGR delete anyway. Which, although I've been trying to find instructions online to determine if it's something I want to tackle or not, I'm sure that takes the turbo off anyway. Two birds with one stone maybe.

Brake Kleen....oooookayyy, make sure I'm far away, when you do that.

As far as your second paragraph is concerned, while what you're suggesting is highly illegal (need to say that, so the post isn't deleted), your hypothesis is correct. I had the EGR permanently "fixed" on my truck, and the power returned instantaneously...no more turbo lag at all and an increase of 1MPG towing (I'll take what I can get).

Truck11 · 08-29-2009, 03:49 PM

Im having the same problem. My boost gauge if fluttering like crazy and and losing power at one point last week the turbo was only making 10psi climbing a hill (had to pull over doing 10mph in first gear not towing.) Shut off truck and restarted and it was fine. Over boosted to 40psi a few days later. Time to go into the shop.