Cm870 low boost

[JimT]

(07-11-2020 )Farmer379 Wrote:  It is a 2005 peterbilt cm870 cpl 8519. Was changed to 8518 by previous owner. I just bought a bully dog ecm tuner and put the economy with power tune on and now only getting 25-30 psi boost. {up to 40 previously} I checked for codes and have 2. pid: 251 fmi real time clock
Sid: 103 fmi turbocharger speed #1

Also have not deleted anything

Not sure what your question actually is. If you are complaining about low boost because of the bully then it's an obvious solution. Best thing to do is get rid of the bully, get an inline 5 or 6 and a laptop with insite 7. Get a hold of the proper ECM file and have it tuned properly. Gotta be careful with the 870's, something about quirks trying to flash new files(?). Anyway, get it tuned properly and disable that EGR. You'll probably find everything working perfectly again. Or you'll be able to diagnose any actual problems that might be hiding behind the currently bad programming.