85 Corvette TPI 1226870


Unfortunately, the 1226870 is an oddball one-year one-model ECM that was only used on the 1985 corvette.  It is for a TPI setup with an electronically controlled distributor and features 160 baud ALDL communication for logging.  It is a unique ECM.  There are no other ECMs that are a “plug and play” swap without extensive wiring changes. (see “ECM Conversions” below) The ECM uses a 24 pin 2732 EPROM.  A G2 0.6″ chip adapter (solder/desolder install) can be used to install a 28 pin chip or use any of our OBD1 GM tuning gear.

No other masks from other ECMs can be trivially used.  It uses the $1F mask, which is supported by TunerPro RT.

Hardware Required for Tuning

  • G2 Chip adapter and C2 27SF512 chip required to reprogram ECM.  WARNING: This is NOT plug and play!  Desoldering factory chip is required and soldering install for G2 adapter.  (view install)  Order the “Install Service” and send us your ECM if you’re not comfortable with soldering work.
  • BURN2 Chip Programmer programs 27SF512 chips
  • ALDU1 with CABL1 required for datalogging
  • Ostrich2 and SocketBooster 1.0 required for real time tuning
  • APU1 AutoPROM All-in-one device works great (without SocketBooster), taking the place of BURN2, ALDU1+CABL1 and Ostrich2
  • APU1 works great for the application and is the recommended hardware in addition to the G2.

Software Required for Tuning

These computers use the $1F mask from the factory.

TunerPro RT + the $1F definitions works for editing and datalogging.  (this is the recommended software.  It is included with the AutoProm)  Additional/alternate definitions available from Gearhead-efi.com

TunerCat OBD1 tuner with the $1F definition works for editing.

WinALDL works for datalogging.

ECM Conversions

(disclaimer: blatant opinion) The 1226870 is not the high point of OBD1 GM engine management.  It is possible to swap to other ECMs which do better.

1227165 (86-89 TPI MAF) swap

1227730 (90-92 TPI MAP) swap

12200411 (99-02 F body) swap