Page 3 of 3 FirstFirst 123
Results 41 to 53 of 53

Thread: HP Tuners Now Offering JTEC Support!

  1. #41
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    244
    I see that it references barometer on page 10, but doesn't explain if there is a separate sensor or whether or not it is picked up from the MAP. The older cars had a 3 way solenoid that would toggle the pressure source from the manifold source to atmospheric at times to get a sample. Being as the map sensor is directly mounted to the throttle body on a Magnum engine, that would not be the case here. So unless there is a separate sensor somewhere (which I can't find listed as a replacement part) I have to assume that sample comes from the MAP sensor during cranking.

  2. #42
    Advanced Tuner
    Join Date
    Mar 2018
    Location
    Illinois
    Posts
    450
    On a side note, how would you defeat the baro learn? I don't recall seeing an option to disable it?

    On page 54:

    "Anytime the PCM sees at least 1.8 volts above minimum TPS, and based upon rpm, it will update barometric pressure in the MAP memory cell. With periodic updates, the PCM can make its calculations more effectively. Also, if MAP is ever greater than Baro, such as coming down from a high altitude, Baro automatically updates"

  3. #43
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    244
    Quote Originally Posted by Homer View Post
    On a side note, how would you defeat the baro learn? I don't recall seeing an option to disable it?

    On page 54:

    "Anytime the PCM sees at least 1.8 volts above minimum TPS, and based upon rpm, it will update barometric pressure in the MAP memory cell. With periodic updates, the PCM can make its calculations more effectively. Also, if MAP is ever greater than Baro, such as coming down from a high altitude, Baro automatically updates"
    There are a lot of boosted Magnums running around with a 2 bar map and SCT tune from FlyinRyan, so it's obviously possible.

    34042 - Altitude Fuel Compensation <- Maybe zero all that out and hope for the best?

    Maybe there is something under airflow>general that I can't see with my MPVI? Or maybe I just don't understand what I'm seeing there?

  4. #44
    Tuner in Training
    Join Date
    May 2006
    Posts
    17
    I have been running my viper boosted for the last year. I guess I dont see what you mean by changing the 105 to a higher value. I would assume that is a hard limit of the JTEC OS. Anything that references the MAP just has to be split in half. You have to consilidate the fuel and spark tables down to the first 5 rows and build the remaining rows from scratch. I get its just reference numbers but the ECU is retricted to the 105 (787 torr) hard limit. Its the same with the SCT software.

  5. #45
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    244
    Quote Originally Posted by jasond29 View Post
    I have been running my viper boosted for the last year. I guess I dont see what you mean by changing the 105 to a higher value. I would assume that is a hard limit of the JTEC OS. Anything that references the MAP just has to be split in half. You have to consilidate the fuel and spark tables down to the first 5 rows and build the remaining rows from scratch. I get its just reference numbers but the ECU is retricted to the 105 (787 torr) hard limit. Its the same with the SCT software.
    I get that. You just need to mentally adjust by doubling when tuning - anything over 50kpa is actually boost (100kpa+). Just makes it messy compared to what can be done in the newer stuff.

    Do you know what the solution is for SCT to keep the barometer in check?

  6. #46
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    244
    Quote Originally Posted by Homer View Post
    On a side note, how would you defeat the baro learn? I don't recall seeing an option to disable it?

    On page 54:

    "Anytime the PCM sees at least 1.8 volts above minimum TPS, and based upon rpm, it will update barometric pressure in the MAP memory cell. With periodic updates, the PCM can make its calculations more effectively. Also, if MAP is ever greater than Baro, such as coming down from a high altitude, Baro automatically updates"
    P52:

    "The first thing that
    happens as the key is rolled on, before reaching the crank position, the PCM powers
    up, looks at the MAP voltage, and based upon the voltage it sees, it knows the
    current barometric pressure relative to altitude."

  7. #47
    Tuner in Training
    Join Date
    May 2006
    Posts
    17
    Yes it uses the MAP sensor to determine BARO

  8. #48
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    244
    Quote Originally Posted by jasond29 View Post
    Yes it uses the MAP sensor to determine BARO
    So how do you get around an out-of-range barometer reading?

  9. #49
    Tuner in Training
    Join Date
    May 2006
    Posts
    17
    It will never read out of range. Key on will read half not double so it will be within range. The map is still 0-5v sensor so it will read 2.5v or whatever the conditions dictate.

  10. #50
    Advanced Tuner
    Join Date
    Mar 2018
    Location
    Illinois
    Posts
    450
    Quote Originally Posted by jasond29 View Post
    It will never read out of range. Key on will read half not double so it will be within range. The map is still 0-5v sensor so it will read 2.5v or whatever the conditions dictate.
    Oh so boost does not impact baro learn?
    Last edited by Homer; 1 Week Ago at 01:33 PM.

  11. #51
    Advanced Tuner
    Join Date
    Mar 2018
    Location
    Illinois
    Posts
    450
    Quote Originally Posted by spoolboy View Post
    P52:

    "The first thing that
    happens as the key is rolled on, before reaching the crank position, the PCM powers
    up, looks at the MAP voltage, and based upon the voltage it sees, it knows the
    current barometric pressure relative to altitude."
    Yes it establishes baro at KOEO but it also monitors while driving.

    "During key–ON (engine not running) the sensor reads (updates) barometric (Baro)pressure. A normal range can be obtained by monitoring a known valid sensor.As the altitude increases, the air becomes thinner (less oxygen). If a vehicle isstarted and driven to a very different altitude than where it was at key ON, thebarometric pressure must be updated. Anytime the PCM sees at least 1.8 voltsabove minimum TPS, and based upon rpm, it will update barometric pressure in theMAP memory cell. With periodic updates, the PCM can make its calculations moreeffectively. Also, if MAP is ever greater than Baro, such as coming down from a highaltitude, Baro automatically updates."

  12. #52
    Advanced Tuner
    Join Date
    Nov 2017
    Posts
    244
    There has to be a place in there to rescale the map sensor. Maybe it's the tables in airflow>general, but they aren't well defined. Sometimes I can get a clue about a field by right clicking and looking for the "units" (kpa, volts, etc), but not on these tables.

    The 244 map scale multiplier could be what we're looking for, but I don't fully understand it or why it's 244. Maybe it's .244V?

  13. #53
    Advanced Tuner axekick's Avatar
    Join Date
    Aug 2009
    Location
    Austin, TX
    Posts
    326
    I posted in another thread but I'll add my 97 Cherokee stock tune here. I just pulled it. The read went fine and took about 4 minutes. However, I tried setting up my scanner and the MAP Kpa was just stuck at 60. The MAP sensor voltage was scanning so I could set up a table based on voltage to do some tuning. Also, my trims didn't seem to be updating either. Maybe it's my Jeep and not the scanner but until I can figure that out, I can't really tune it. Has anyone here had any luck scanning against the stock tables with the new version of the software?

    Also, I don't see a way to upload my tune to the repository. Is that not enabled yet?
    Attached Files Attached Files
    2006 Tahoe
    Iron ls2, built up 4l60e w/vig 3000 stall, 232/234 114, 4.30s, LTs, ORY NNBS intake and LS2 TB etc.

    Fighting solves everything...
    ...except partial differential equations.


    Click here to combine multiple VE Logs into one.