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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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
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.
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
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,Quote:
Originally Posted by EagleMark
The Memcal modification show in the attached pic is NOT needed for MPFI?
dave w
That's what I said but I guess it did not come out well?
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
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 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, the '7427 also controls shifting of the trans in it's original application.Quote:
Originally Posted by Aholt91ss
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.Quote:
Originally Posted by Six_Shooter
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.
No VSS? Not a good PLAN! The '7427 really likes knowing when to use the Near Idle / Off Idle Tables!!!!!!!!!!!Quote:
Originally Posted by Aholt91ss
dave w
i was planning on buying this
90-92 TPI Retrofit Vehicle Speed Sensor - 4000 Pulse
I'm thinking this would be the correct VSS for the '427 PCM - 2000 Pulse http://www.tpiparts.net/inc/sdetail/7586Quote:
Originally Posted by Aholt91ss
dave w