625 ecm TBI swap

[Aceman]

I am currently swap a TBI setup onto my 79 corvette to replace to slobbering 4bbl carb. Donor is a 93 chev 1500 5.7 with a 4l60e. It has the 625 PCM. I have sorted thu the harness and installed it with the complete tbi setup. I have not installed the 4l60e yet, but plan to over the winter. Problem is it will not run. When i turn the key the fuel pump will run for 20-30 seconds which seem longer then it should, then when i crank i get no injector fuel spray or spark. Will the trans not being connected stop the engine from running ? I have grounded the blue trans wire and tunerpro reports position as neutral. Codes that i get are 12, 43, 59, 67, 81 and 82. None that i think will stop it from running. The truck did run and drive before i pulled the motor and trans. Any help troubleshooting would be great. Thanks

[dave w]

It might be a faulty ignition module in the distributor. The ignition module supplies the computer with a reference pulse (RPM) so the computer will trigger the injectors to pulse fuel, and let the computer know it's time to control spark once the computer see greater than 400 RPM's reference pulse.

Have you re-programmed the PROM Chip?

dave w

[Aceman]

Well pulled the cap and replaced the module, same problem . Pulled the distributor and replaced the pickup coil and started right up. It is strange that it ran before the swap tho. The pickup coil had obvious signs of deterioration. Thanks for pointing me in the right direction.

[Aceman]

I have all the moates equipment APU1 chips etc, made a few data logging cables from usb -> ttl convertors as well. Current bin is stock with egr disabled, rpm limit to 6000 (4800 wasnt going going to work with THM 350 kickdown shifts), speed limiter to 255 (not that it matters without the 4l60e trans installed yet),and adjusted the idle fuel table some as it is a bit rich there. Runs pretty good. Currently im trying to figure out the timing. If i set the base timing at 0 deg , it runs like crap when the timing connector is plugged in, like its retarded too much. If i advance the distributor, it runs much better. Should the tbi timing table be changed quite a bit for the ex-carbed engine? or base timing be advanced quite a bit ? I rolled the crank back and forth, the rotor button has a little play ( ie. timing chain play) , but i have seen much worse. Thanks

[Aceman]

So I set the base timing @ 10 deg and entered it in the ADX. Starts good, idles smooth, but response slow and power is low. On to advancing the timing map. Zero knock counts.