If I remember right the optical VSS output from your speedo conversion is 2000 ppm and the TPI ECM wants to see 4000 ppm. I think you will have to run that optical VSS output through a DRAC like the stock TBI trucks did but use the 4000 ppm output from it to feed the TPI ECM instead of the 2000 ppm output the TBI ECM used.
It may run fine but the tune will be off since the ECM will think you are going half as fast as you actually are. It will mess up the coolant fan cut off speeds and not allow you to make highway mode work properly too.
Highway mode is one of the coolest features of the 8D programming for the 1227730 TPI ECM. Even though it was disabled in stock form for emissions reasons the programmers were nice enough to leave it in the code so we could reactivate it
My 91 Z/28 jumped from 24 mpg on the freeway to 30 mpg after I turned on highway mode.
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miSSed opportunity - ground up creation of an AWD 1994 454 SS that never was
http://67-72chevytrucks.com/vboard/s...d.php?t=795577
69 C10 shortbed stepside 400 small block - built like what a super sport truck could have been
69 K20 lwb TBI 350 4L60E NP208 14-bolt Dana-44 w/disc
68 Camaro SS / RS 500hp 439 inch roller cam big block 4L80E
79 Malibu TPI 350 4L60 w/ Z28 steering & sway bars