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Need information about PCM

Posted by MADBADGER, Mar 21, 2012

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  1. MADBADGER

    MADBADGER Probationary Member

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    Joined Jul 12, 2010
    Zanesville, Ohio
    I'm attempting to simulate the PCM on my 95 eagle talon using a computer program (labview). Basically I need to know what the pcm does with each input to get the output.

    For example: PCM takes in voltage from O2 sensor .. does some calculation.. outputs voltage to injector. The does some calculation is the part I need to know. I have no idea the range of voltage the injector operates on. What voltage does it idle at?

    I still need to do alot of research on this but if anyone has any information I could use I would be forever gratefull.

    Thanks
     
  2. ed1380

    ed1380 Supporting VIP

    2,324
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    Joined Sep 29, 2007
    ATL, Georgia
    Ecu takes crank signal (2x per revolution) and uses it to fire coil A or coil B

    Cam sensor spins at half the engine rpm and pulses 4x per revolution (every other crank revolution) and that gives signal for the injectors.

    Tps outputs 0-5v based upon throttle position.

    O2 sensor outputs a .1 to .9v signal .1-.4 is rich and .5-.9 is lean. It pretty much says too rich or too lean, hard it.

    Ecu is capable of operating in open loop and closed loop.

    Open loop is used before o2 sensors and coolant warms up and at wot (70+% tps). Open loops works straight off the programmed tables.

    DSM maf sensor outputs a frequency relative to the amount of air flowing. Every .51lbs/min of air is 32hz (thanks to sweet97 for that)

    Load is calculated by the ecu as airflow/rev.

    The fuel maps are 3d graphs with rpm and load as the axis and a target open loop fuel ratio as the value.9

    Closed loops is used during idle and light load. The ecu uses the too rich-too lean signals to fine tune the amount of fuel given to the engine. This fine tune # is stored as a % called the short term fuel trim(stft). It can be positive or negative for more or less fuel. After the stft number has been pretty steady it is stored as the long term fuel trim(ltft). Dsm's actually have 2 stft and 2ltft. It takes about 16minutes for a value to go from stft to ltft. Clearing check engine light or disconnecting battery also clears the fuel trim causing a car to stuble if you clear the check engine codes while it runs.
     

    998  0

    1999 Mitsubishi Eclipse GSX
    · 2G DSM
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  3. MADBADGER

    MADBADGER Probationary Member

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    Joined Jul 12, 2010
    Zanesville, Ohio
    Wow thanks for the reply thats some great information... If theres anything else anyone can give me it would all help!
     
  4. rts91tsi

    rts91tsi Proven Member

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    Joined Feb 3, 2009
    Rockford, Michigan
    I recommend looking into the dis-assembly of the 95 code and other good info available from: 95 EPROM « ceddy.us

    Also, the technical manual has good info about the various sensors and their function.

    Does labview has the ability to simulate test equipment like an oscilloscope, logic analyzer, and DMM?
     
  5. MADBADGER

    MADBADGER Probationary Member

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    Joined Jul 12, 2010
    Zanesville, Ohio
    Yes labview has those capabilities, very sophisticated programs can be written with labview.. if you know what your doing.

    I just have a basic understanding unfortunately but its simple and easy to figure out. My first intention was to do it all in code but this would be way easier
     
  6. dexterholland04

    dexterholland04 Proven Member

    641
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    Joined Jan 1, 2007
    Rush, New York
    Do you know what uprocessor the ECU uses? It would kind of be cool if I could get this working on a PPC core on one of the Virtex 5 or 6 FPGAs I've got.
     

    4K  5

    1995 Eagle Talon TSi AWD
    10.1 @ 149.02 · 2G DSM
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  7. rts91tsi

    rts91tsi Proven Member

    191
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    Joined Feb 3, 2009
    Rockford, Michigan
    Honestly, I haven't looked into the 2g ECU much, since I'm a 1g owner. If you have a 95 ECU handy, pull the cover, and Google or all data search the processor numbers for specs. Although, I'm not sure how much luck you'll have, because they are probably hybrids, like the 1g ECU.
     
  8. Spanky_DSM

    Spanky_DSM Proven Member

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    Joined Sep 28, 2010
    El Paso, Texas
    Will a 2g turbo Power control module fit a 1g turbo dsm?
     

    764  0

    1995 Eagle Talon TSi AWD
    automatic · 2G DSM
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  9. ed1380

    ed1380 Supporting VIP

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    Joined Sep 29, 2007
    ATL, Georgia
    It has been done, but requires harness adapter or lots of soldering.
     

    998  0

    1999 Mitsubishi Eclipse GSX
    · 2G DSM
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  10. undefined0000

    undefined0000 Proven Member

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    Joined Sep 2, 2012
    Findlay, Ohio
    *butts in

    Isn't there a difference between our ECU/TCU setup and PCM like in GMs.

    Doesn't the PCM handle both the transmission and engine while our engines and A/Ts are on separate systems?
     
  11. wrencher

    wrencher Proven Member

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    Joined Nov 20, 2005
    Chicago, Illinois
    In generic terms the "PCM" is post to be power train control module.
    So yes trans control can be integral. But there are others that have a TCM/TCU & also a PCM. So it is not a rule by any means.
     
  12. ed1380

    ed1380 Supporting VIP

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    Joined Sep 29, 2007
    ATL, Georgia
    IIRC there are only 2 wires between the tcu and the ecu. Something about load. But if you're going to the extremes of putting a 2g ecu in a 1g, you might as well do the manual shift mod and get rid of the tcu.
     

    998  0

    1999 Mitsubishi Eclipse GSX
    · 2G DSM
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