no power in upper RPM **Now with Video.

[gldgti]

leaky intake manifold... like not bolted to the head correctly?

if there's not much boost, the LDA is doing nothing, so that could account for lack of smoke.

[jtanguay]

the reason i asked where your taking your boost measurement is because i had a similar problem.  turned out to be a line disconnected.  but i was getting 0 boost pressure as i T'ed into the line going to the LDA, and it disconnected at the manifold.

could be that or leaky manifolds, IF the turbo is in fact good.

[zozep]

I have a line running from the boost controller that Dr. Diesel made for SMOKEYDUB, up to my boost gauge. The most I ever read was 15 lbs of boost, then apparently the Wastegate failed, and is stuck open. Its gonna get swapped I guess.


I'll take a picture of the setup.

[zozep]

So heres a video, at 5mins you can see the issue I was talking about... only for a few seconds, but its there, once i'm into 2nd It humps a bit at a certain RPM range....
Anyone have any ideas? I got the boost issue figured out...but I need to know how to adjust the controller to make more than 15psi...
anyway...

http://www.youtube.com/watch?v=8hCk3MxTWnA

[arb]

Maybe I'd old school, but I've never taken a diesel above 4K rpm ;-)

On the issue, a harmonic or residence in your fuel or valve system ? I would just stay out of that range. There are some certified aircraft with this type of problem and they have a restriction not to fly with the engine from 2450 - 2525 rpm (example - maybe other #) as there is a harmonic resonance in the engine / prop system.

[zozep]

hmm, forgive me but I reject this... I'm not sure how anyone on here who claims to make 15-25 psi do it without hitting 4k rpm. For longevity You're likely spot on, not something you want to do at every light, I do it to pass.

Back on topic, again, I reject what you're saying on the basis that it didn't do this on the pump before I had it Gilesified. I don't want to blame it on the pump, I talked with Tyler, he told me he had a guy with this same issue and it was that the pump was not secured tight enough and the vibrations were causing the pump to change timing mid acceleration...which is the exact symptom, it jerks as if its trying to pump more fuel if I keep it steady at around 2400-2600 rpm (very annoying because I can either drive at 95kmph or 110kmph, I like to drive at 100). This can't be the cause, I know that this pump is locked in tight.  :?   :?:
Another observation is that when it gets to that rev range, the accel pedal vibrates and I feel it all through my foot...

[blkboostedtruck]

Maybe I'd old school, but I've never taken a diesel above 4K rpm ;-)

it don't sound like you ever had a modified pump! my last one would top out at 5500rpm and zukgod1 built that one now i got a giles and it's good for 6000rpm easy! what a blast to drive!
Duane

[arb]

Maybe I'd old school, but I've never taken a diesel above 4K rpm ;-)

it don't sound like you ever had a modified pump! my last one would top out at 5500rpm and zukgod1 built that one now i got a giles and it's good for 6000rpm easy! what a blast to drive!
Duane

Completely true. All of my diesels have been for 2 goals: low fuel burn and long life. Only recently has diesel become the real choice for performance.

So, I have never had a reason to go beyond 4,000 rpm. What is our "red line" ?  4,600 ? And what is a red line? To me, the rpm's that the average stock, Un-blue printed engine can be ran before things come unglued, with some margin of safety. What speed will the IDI come unglued and throw a rod ? I have no idea. I have only thrown a rod once in my life, and that was a Chevy small block.

[zozep]

hmm...harmonic resonance eh? sounds possible...I guess.. So you're saying that by some fluke, the sum of say, timing, wear of the engine, all other things are making it that at that RPM the engine is resonating and creating this issue?

I'm usually one for a more simple explanation... Hey Giles/Tyler any other ideas? I've run the tank through the old diesel that was in there, and now I have winter grade stuff in there and some addiditve.

[Duster 5.9]

i'm taking that the top left gauge is the boost guage? can you pinpoint it to a certain boost? i'm thinking it is a boost lag

[blkboostedtruck]

i listened to your vid! to me that sounds like either wheel bearings or the bearings in the trans by the flanges? does it mostly make that noise at high speeds? is that what your talking about? i could not read your pillar gages! just your speedo and tach! my rabbit made that resonating noise and i know it's just old worn multable bearings! i would run a wheel bearing till it came apart! then when i fix it it would be a little quieter !
so i know it was mostly all drivetrain and rear wheel bearings!
anyways am i hitting what your talking about?
Duane

[zozep]

If you watch the video again, at 5Mins I start again from 0kmph. at 5:16 thats when it happens, its a jerking that only happens between 2500 and 2650 RPM in slow acceleration. I can start feeling a heavy vibration in the accel pedal and then it jerks....
You're right Duane, I do need rear wheel bearings, good ears at hearing that. But no, I dont think this is a wheel bearing issue. It happens at all speeds depending on RPMs, again, only between 2500 and 2650...either keeping it constant or slowly accelerating through that range....

[Giles@PerformanceDiesel]

try undoing the rear bolt and then tighteningit again.
is it the original tapered bold?

how the belt tension? the drive line could also be a problem
you said you didn't have this before i did the pump, have you
changed anything else?

it could also be the pump's Light Load Retard function if you
can't find anything else then call me we'll discus other things.

Giles