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Thread: Desired ICP Low compared to Desired in VCM Editor

  1. #1
    Tuner in Training
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    Desired ICP Low compared to Desired in VCM Editor

    Upon all my logging lately I've come to find the Desired ICP my truck is calling for while cruising is close to half of what the Calibration file shows under the Fuel System tab. Is this a result of ICP Feed Forward Duty Cycle vs ICP vs IPR Flow table? Only thing I can think of is to bump up the corresponding Duty Cycles, but cannot find any kind of pump flow rates for my 2005 6.0 truck, nor any other. I can imagine it has to be rated for a certain flow ( at a given RPM. Thanks!

  2. #2
    Advanced Tuner RandomEnthusiast's Avatar
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    It's a combination of demand and a couple other parameters as far as I can tell. I got it to bump to max ipr% when you smash the pedal and modified the mid end. It's only open loop control so it's sort of limited. I guess you could force fail the maf and it would constantly be openloop. I just never had any issues. Is it falling on it's face mid range or anything?

  3. #3
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    No issues to speak of. Just doing my best to learn control of the injection events before increasing fueling much. ICP and pulse width has been very useful in calculating my timing and really brought her to life from stop.

  4. #4
    Advanced Tuner RandomEnthusiast's Avatar
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    You can modify ICP desired and get a lot of good results. I played with pedal filter and off idle and the top end and it helped alot with stop and go. I no longer have a test candidate because the truck I was learning on got sold. It held 28 psi on stock headbolts. I'm guessing it was a fluke and luck. It made really good power down low and up high. Timing I just monitored EGTS. If it looked like egts were out of control I'd back out a bit of timing and pull some fuel.

  5. #5
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    Bump for this issue, as I've made a similar discovery on a 04 6.0 PSD I'm working on.

    So, what's the deal with the ICP Desired not following what is written in the calibration? We're not talking about a discrepancy between Desired and Actual. I can command 25 MPa at a given point in the map (say, 1600 RPM vs 66 mg fuel), and when I log those exact operating conditions, I only see 16.7 MPa Desired and Actual on the scanner.

    Are we missing a table somewhere that defines a limit on pressure against another PID? Anyone been able to get exactly what they command in the file? I feel like it's especially noticeable at lower RPMs. Perhaps there's a table that limits max ICP vs RPM that isn't defined and available for editing?

    Thanks for any input anyone can offer!