Jump to content
  • 0

2009 mp8 485 no power



I have a 2009 CHU613 heavy haul truck with the mp8 485hp engine.  The engine starts and runs absolutely perfect with excellent throttle response.  If you mash the throttle through the first 3 gears the truck will pull unbelievably well.  After approx 20mph the truck falls flat on its face.  It will not maintain speed pulling an empty or loaded trailer.  I have checked fuel pressure, boost pressure, blown Venturi tubes out, pulled vgt actuator off and moved linkage back and forth (free and smooth as silk) calibrated vgt, checked engine torque settings, checked road speed limit, checked for intake leaks, etc.  There are no codes present.  I have no idea what else could cause the problem.  Also, this truck will burn 2.5 times more fuel on a similar trip than any other truck I own.  Could horspower not be set at what valve cover sticker says?  How do you check current ecm hp/torque settings?  What else could be the problem here?

75psi fuel pressure

28-35psi boost



Link to comment
Share on other sites

6 answers to this question

Recommended Posts

  • 0

I have not checked for a torque limiter on the transmission.  I have not changed the tire size either but that's not to say the tires weren't changed before I got the truck.  I will check tire size setting/calibration and see what it is.

like I was describing earlier, the truck runs perfect.  No miss, sputter or anything like that.  In the low gears 1-3 the truck will almost scare you on how hard it pulls.  Once you hit the road it's like the truck is totally de-rated and doesn't even try.  Downshifting doesn't really have any positive results either.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Answer this question...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...