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We are privately owned, with access to a professional Diesel Mechanic, who can provide additional support for Dodge Ram Cummins Diesel vehicles. Many detailed information is FREE and available to read. However, in order to interact directly with our Diesel Mechanic, Michael, by phone, via zoom, or as the web-based option, Subscription Plans are offered that will enable these and other features.  Go to the Subscription Page and Select a desired plan. At any time you wish to cancel the Subscription, click Subscription Page, select the 'Cancel' button, and it will be canceled. For your convenience, all subscriptions are on auto-renewal.

2008 6.7L 'fuel derate' and no codes

Posted

sub 10k miles on new Bosch OE injectors
RaceMe Pro tuned (60hp setting, #3), deleted.
5" FloPro exhaust

For a long time, now, I've been getting a fuel derate under heavy throttle loads (like climbing a 4-5% grade in 5th or 6th) at like 40% or more throttle percentage.
As an example, logging with my XTOOL A30D scanner:

  • 60% throttle
  • 5th gear
  • about 55mph
  • loaded or empty, doesn't matter

Fuel pressure requested set point:  21000psi
Fuel pressure Sensor:  15000psi (more throttle decreases this pressure, I've seen it as low as like 8000psi)
HPCR Fuel Pressure:  follows fuel pressure sensor

After about 5-8 secs of this gap in requested pressure, the Derate Counter increments by 1, the engine gets flat (100% throttle makes no change) and the overhead console dings "See Dealer".
no codes are stored...


Things I've done: 

  • I've updated the tuner's firmware
  • re-flashed the truck
  • replaced fuel filters
  • replaced the Fuel Pressure Sensor
  • Replaced Fuel Pressure Relief Valve with a Plug
    • Re-shimmed OE FPRV
    • Replaced with Bosch new FPRV
  • Changed to a lesser tune, as well as a higher tune
  • tried stepping up the rail fuel presser
    • no change, set back to stock

Last thing, I've ordered a FLEECE 170 lift pump, that will be here tomorrow.. 

The 'NO CODE' part is a MFer, since that gives me absolutely no direction.

 

Thoughts?  I'm at a loss, and I've been chasing this issue for a very long time.

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Welcome To Mopar1973Man.Com LLC

We are privately owned, with access to a professional Diesel Mechanic, who can provide additional support for Dodge Ram Cummins Diesel vehicles. Many detailed information is FREE and available to read. However, in order to interact directly with our Diesel Mechanic, Michael, by phone, via zoom, or as the web-based option, Subscription Plans are offered that will enable these and other features.  Go to the Subscription Page and Select a desired plan. At any time you wish to cancel the Subscription, click Subscription Page, select the 'Cancel' button, and it will be canceled. For your convenience, all subscriptions are on auto-renewal.