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Thread: 305 tpi with 7427 pcm Possible?

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    Fuel Injected! Aholt91ss's Avatar
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    305 tpi with 7427 pcm Possible?

    I have an 85 Camaro with a bad 6870 ecm and want to know if any body has run tpi with a 7427 pcm or if possible to run one
    i have a spare 7427 pcm

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    if MPFI mods were done to the 7427, i don't see any reason why not. i'm sure it's been done before as well.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


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    Fuel Injected! Aholt91ss's Avatar
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    would you know what sorts of mods?

    my understanding 6870 has one injector driver whereas the 7427 has 2 but resistance of injectors would proabably be different
    Last edited by Aholt91ss; 06-15-2013 at 07:09 PM.

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    EFI GearHead ! EagleMark's Avatar
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    There's a couple resisters in PCM that need a solid jumper for 8 injectors. The Memcal mod with a wire when you read docs is not needed. Take a look in this thread for links to wiring and a Zip file with all that needs to be done to convert 97427 TBI to MPFI:
    http://www.gearhead-efi.com/Fuel-Inj...Information-OD

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
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    Super Moderator dave w's Avatar
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    Quote Originally Posted by EagleMark View Post
    There's a couple resisters in PCM that need a solid jumper for 8 injectors. The Memcal mod with a wire when you read docs is not needed. Take a look in this thread for links to wiring and a Zip file with all that needs to be done to convert 97427 TBI to MPFI:
    http://www.gearhead-efi.com/Fuel-Inj...Information-OD
    Mark,
    The Memcal modification show in the attached pic is NOT needed for MPFI?

    dave w
    Attached Images Attached Images

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    EFI GearHead ! EagleMark's Avatar
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    That's what I said but I guess it did not come out well?

    1990 Chevy Suburban 5.7L Auto ECM 1227747 $42!
    1998 Chevy Silverado 5.7L Vortec 0411 Swap to RoadRunner!
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    Fuel Injected! Aholt91ss's Avatar
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    so the only modification is the 2 resistors replace with solid wire and go in tp and set flags
    and repin the connectors do i need to wire each of bank of injectors in parralel or leave it alone

    and probably have to run a map sensor speed density instead of maf
    Last edited by Aholt91ss; 06-16-2013 at 07:22 AM.

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    Super Moderator Six_Shooter's Avatar
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    How is that the jumper is not needed?

    From my understanding this puts the PCM in 8 cyl PFI mode on the hardware side, just like is needed in other ECMs for MPFI.

    I think for simplicity reasons in this case, I would look at using the '165 ECM and $6E or swapping to speed density using a '7730 and $8D.

    Back when I tried running a '7427 PCM without the E-trans it didn't run as well as with the E-trans. Same vehicle, just a trans swap from a TH350 to 4L60E, no other changes, other than loading a stock bin to the ECM to re-enable trans control and it ran 10 times better. I made all of the recommended changes to run a non E-trans and was just never satisfied without how it ran until the trans was swapped. It was always the intention to swap the E-trans in, just did the EFI swap first.
    The man who says something is impossible, is usually interrupted by the man doing it.

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    Fuel Injected! Aholt91ss's Avatar
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    the local pick a part only has one 91 camaro that stripped to bare nothing and i already have a few 7427 pcms

    the pcm only controls lockup doesnt it? also i dont have vss
    Last edited by Aholt91ss; 06-16-2013 at 07:58 AM.

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    Super Moderator Six_Shooter's Avatar
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    Quote Originally Posted by Aholt91ss View Post
    the local pick a part only has one 91 camaro that stripped to bare nothing and i already have a few 7427 pcms

    the pcm only controls lockup doesnt it?
    No, the '7427 also controls shifting of the trans in it's original application.

    To run with a non-E trans there's a significant amount of needed modification to the bin file.
    The man who says something is impossible, is usually interrupted by the man doing it.

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    Quote Originally Posted by Six_Shooter View Post
    No, the '7427 also controls shifting of the trans in it's original application.

    To run with a non-E trans there's a significant amount of needed modification to the bin file.
    There are only a few bits that I remember having to change to go back and forth and I noticed no engine difference, but much better driveability with the 4L60E trans.

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    assuming the 7427 works like all of the P4 units... the MEMCAL cylinder select is only ever USED when in limp-home.... it's READ all the time to attempt to verify if an incorrect/failing MEMCAL is installed.

    on a 7727 type unit, i've switched them around, disabled the DTC and so long as it never went into LHM, injector to DRP sequencing was set to whatever the BIN was. go into LHM, then the cylinder select pins actually get used.
    1995 Chevrolet Monte Carlo LS 3100 + 4T60E


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    Super Moderator dave w's Avatar
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    Quote Originally Posted by Aholt91ss View Post
    the local pick a part only has one 91 camaro that stripped to bare nothing and i already have a few 7427 pcms

    the pcm only controls lockup doesnt it? also i dont have vss
    No VSS? Not a good PLAN! The '7427 really likes knowing when to use the Near Idle / Off Idle Tables!!!!!!!!!!!

    dave w

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    Fuel Injected! Aholt91ss's Avatar
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    Super Moderator dave w's Avatar
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    Quote Originally Posted by Aholt91ss View Post
    I'm thinking this would be the correct VSS for the '427 PCM - 2000 Pulse http://www.tpiparts.net/inc/sdetail/7586

    dave w

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