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Thread: Line Pressure PID for 4L80?

  1. #11
    Joe (Moderator) joecar's Avatar
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    The pins on the orange blocks do not emit 5V or any voltage. They are inputs only.

  2. #12
    Joe (Moderator) joecar's Avatar
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    The TE seems to be the simplest/quickest approach.

    Connect the sensor to 5V and 0V from the TE.
    Connect the sensor output to FSV2 AD1+.
    Connect the sensor 0V/gnd to FSV2 AD1-.

    Does the sensor 0-5V output range represent 0-300psi...?
    We can easily make a calc pid for this.

  3. #13
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    Quote Originally Posted by joecar View Post
    The TE seems to be the simplest/quickest approach.

    Connect the sensor to 5V and 0V from the TE.
    Connect the sensor output to FSV2 AD1+.
    Connect the sensor 0V/gnd to FSV2 AD1-.

    Does the sensor 0-5V output range represent 0-300psi...?
    We can easily make a calc pid for this.
    From what I can see, it outputs .5V-4.5V if you put the 5V into it. I figure I should call to make sure, but am assuming for the moment that that either represents 0-300psi or 300-0psi.

    You're saying that the ground needs to be fed into both the FSV2 and the TE, right? I can't seem to find a good tutorial on the A/D stuff, is there a good link somewhere that I'm missing that covers the basics?
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  4. #14
    Joe (Moderator) joecar's Avatar
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    Yes, same ground to TE, sensor and FSV2.

  5. #15
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    Quote Originally Posted by Supercharged111 View Post
    Were you able to log it too? Or just eyeballed the 2 real time? I'm hoping to use the external A/D inputs but having a hard time finding a tutorial that talks about them. I can find 400 psi oil pressure sending units all day long.

    Joe that drawing is going to take me a little more to digest, but once I have my answer on actual line pressure I think it'll be even more helpful.
    If you wire that 0-300PSI sensor to the PCM like the tutorial says to do with the Fuel Pressure sensor you can datalog it and compare to the PCS signal from PCM.
    The gauge i use the most is just a 400psi gauge on the end of a nitrous hose, its the easiest way to double check line pressure and such. But on my personal truck i have the 400psi sensor wired to the PCM just to datalog it.

  6. #16
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    Next question: could I make a pid that took in the PCS's value and outputted a theoretical commanded line pressure value? I think it'd be cool to have that and the logged line pressure overlaid on the 2D screen that plots the values over time. After poking around, it seems this may be a good starting point?

    Quote Originally Posted by Blacky View Post
    Check out the example "User Defined PIDs" files in the latest EFILive release: \Documents\EFILive\V8\User Defined PIDs

    If you add/change any PID definitions, you need to compile them using the \Program Files (x86)\EFILive\V8\EFILive_UserPID.exe application.

    Regards
    Paul
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  7. #17
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    Got the sensor, some crimpers, and 20/3 wire on the way now to make this a nice, clean install. The sensor includes a plug and pins.
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  8. #18
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    You gonna wire it thru the EGR input?

  9. #19
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    Quote Originally Posted by nonnieselman View Post
    You gonna wire it thru the EGR input?
    Whatever's easier, which in the dually might be the wideband's external 5V function. I forgot all about the EGR though, that's an unused source of 5V as well. We shall see. For now I'm going to flash that new tune and see how it does on the way to the track. Lots of stuff left to do to the Camaro first. Transmission has to come back out as I screwed something up putting it together. Hopefully I get away with just yanking the rear of the case and not blowing the whole thing apart!
    1998 GMC Sierra K1500 5.7/4L80E, longtubes, 411 w/COS 5, marine cam/intake, Whipple. 91 octane at 6000'.
    1997 GMC Sierra K3500 7.4/4L80E, 411 w/COS 3, Whipple, small cam.
    2004 Corvette Z06 with longtubes.

  10. #20
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    for a 300psi sensor: psi = (volts- 0.5) x 75

    75 being 300/4

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