NO BOOST

[Marajin]

Saw a truck a while back that went from making 36-38 boost to 30 refused to go higher. Turbo had 640k miles. Checked everything tested the cac all kinds of everrything. wasn't turbo. wasn't cac or leak. wasnt anything anyone could find. insite was showin nothing. Upped the turbo tables and wouldn't go any higher.

what u guys post here sounds all to familiar.

After digging deep in ecm I found the fuel was being capped off at a lower than normal level seemed for no reason. truck used to run fine, why it change?

Turned out to be to the fuel system that was throwing no codes whatsoever even though all derates disabled on that truck. Theres fuel derate manager with several reasons that can still activate. Is related to fuel system components like wrong resistance on fueling or metering actuators, shutoff solenoid, cam and crank position loosing sync, and a few other. it can sometimes not bad enough to fault but intermittent or only enough engine dont like. -- They are there to protect engine. Is difficult to find wich one it is cause without the use of c*trm. Insite never showed and said everything was fine.

i think is uncommon but does happen i have seen this.

[Rawze]

I have seen trucks with incorrect altitude or ambient temp readings make lower than normal boost or power too, never throw a code.

[smorgan87]

(11-04-2017 )Rawze Wrote:  I have seen trucks with incorrect altitude or ambient temp readings make lower than normal boost or power too, never throw a code.

Bad sensors i gather?

[axe]

(11-04-2017 )Rawze Wrote:  Also, you did not mention how low the boost is and/or how +when it got that way.

It will not boost at all. few pounds, says guage wont hardly move. I'm on my way home and try and see whats going on. Hes covered all the stuff besides somrthing electronic. EGR crossover tube not leaking. This guy has the worst luck, its always something weird. Changes his turbo, we have changed a couple, and now cant go to work, LOL poor Jim. Thanks for all the suggestions and help.

[axe]

(11-04-2017 )Mr Hagg Wrote:  Axe does your friend ever come through GA. or will the truck make it? There are many reasons why you have low boost. Would love to take a look at it to see what it may be. ANd how long ago was it done. May things have changed over the past few years. and like mention before could be egr tube leaking if it was dont along time ago. Or as Rawze mention may be in some sort of silent derate...Just the other day we have a truck that the wiring got on the exhaust pipe after the guy had a clutch put in and who ever did it left the wires loose and it burnt into the 5 volt wire and caused it to through a few odd codes..

No it wont make it Mr Hagg. Thanks so much. When we get it going I would like to bring it over and get you to check it out and update it to the newest mm. It was done right at 2 years ago. Thanks again for willing to help. You guys on here are the best. Hope to see you and Rawze in the near future.

[Rawze]

(11-05-2017 )axe Wrote:  It will not boost at all. few pounds, says guage wont hardly move. I'm on my way home and try and see whats going on. Hes covered all the stuff besides somrthing electronic. EGR crossover tube not leaking. This guy has the worst luck, its always something weird. Changes his turbo, we have changed a couple, and now cant go to work, LOL poor Jim. Thanks for all the suggestions and help.

I have seen the derates that Marajin mentioned and the engine will still run and make 25-30 lb boost. The power is just low is all.

What you describe is not a derate. That is something more severe. Should be easy to find if it is that bad.

[Rawze]

You also mentioned turbo slobber. Make sure the crank case filter or piping is not plugged up and is drilled out properly.

maybe install one of these...
http://rawze.com/forums/showthread.php?t...50#pid8950

also make sure there is positive pressure at intake.