low boost and no power

G Racing

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A friend brought his 03' 6.0 by and dropped it off. He said the last tech gave up. He had dropped a valve and had a remaned engine put in along with a new turbo. The new engine and turbo only have 3500ish miles on it. Before I go and put a stick of dynomite on it I was wondering what the 6.0 wizards would have to say.

The only thing that I can get out of it is a soft code for low boost performance and #5 injector is a bit out. Nothing major on the injector. The truck takes forever to build any boost until 3000rpm then it will take off. It doesn't matter if it is hot or cold it does the same thing. There is no black, white or blue smoke. you can stab the pedal to the floor and it will down shift but won't go anywhere. If you put it in drive and hold the brake and apply some fuel it won't break 1000rpms. The exhaust is not plugged. Temps and everything else look good nothing out of wack. he says that it has done this ever since he picked it up from having the engine put in. I told him to hold the guy to the coals that put it in but he won't return phone calls or anything and he just wants it fixed. I know that I am probably overlooking the big red flashing light but if someone had some insight I would greatly accept any good info. Thanks.
 

jdgleason

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Has he done any elctronics troubleshooting? Maybe try a pcm? Does it start easily? Does it smoke? IPR maybe? FICM possibly?
 

Dzchey21

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has it ever been tuned or reflashed, I have see corrupt files do weird stuff like this too...
 

jngreen

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Do 6.0's have map sensors? My dad's truck (7.3) was doing the exact same thing and I found the rubber hose going to the map sensor was disconnected. It was a real easy fix, and ran exactly as you described. Did not throw a check engine light either, just a soft code for low boost.
 

Dzchey21

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map sensor should be in the intake but i was wondering about the sensor actually being bad.

Can you watch map voltage while you drive?
 

Dzchey21

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you might check voltage, i dont know for sure, i ran around with my map unhooked and it still flashed a boost reading on the dash...like the computer was substituting a boost value...
 

jngreen

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map sensor should be in the intake but i was wondering about the sensor actually being bad.

Can you watch map voltage while you drive?



Yeah I would think that a bad sensor would do the same thing. Dad thought something was really wrong because it had no power, especially while towing, and it would downshift easily but it would not move any faster.
 

G Racing

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Ok I logged and recorded some data. Which I could load the whole file but here are some shots.
5c8f4704.jpg

In the one above the vertical line is the start of making a run, I'm starting to push on the pedal

1bc75c2a.jpg

In this one the vertical line is where it falls flat. Everything is like it's at idle I mean everything flat lines

fb88e4f4.jpg

And here it picks up and takes off and runs like it should
 

jdgleason

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Total shot in the dark... but maybe there is something going on with the tps... maybe the computer isnt getting the right input?
 

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