I recently did the 305CFI-350CFI swap on my 1983 z28. Everything is going to plan, but i need to replace the existing ECM. Can i use the 350 TBI ECM with the number 1228746 or should i purchase an ECM from a 1984 350CFI Corvette with the part number 1225550? When it comes to ECM's and cars, I might as well be performning brain surgery!

 

The '8746 is a better ECM then the stock CFI units. However, they are not plug compatible. The CFI ECMs are edge card connectors while the C3 TBI ECMs (such as the '8746) have pin style connectors.

Can either install a HAM board in the '8746 (www.crossfireinjection.net) or cut off the existing connectors and splice on the pin style connectors. Third option is to swap out the EFI harness.

RBob.

 

Wow haha I didn't realize this was gonna be such a headache! Id rather not splice or replace the harness. I wonder why they ECM's are not compatible. And I didnt even think that would be an issue... hmm can I just put a chip in my existing ECM? Would i get the same affect?

 

For mine i used my original ecm(stock'82,don't know the
#)put an '82 corvette chip in it(for'83 camaro use'84 vette
chip)the injectors are different for 350,so use vette injectors.performance is better if the fuel pump is replaced
with a higher pressure pump(L-98 pump is often used).
I did several mods to mine and it runs strong!.
will give more details if you want.

 

I got the Vette injectors and pump already The chip is a direct fit? I just de-solder the one from the vette and replace the one in my stock ECM? Seems straight forward. Better than cutting the harness IMO . Thanks for the quick responses guys Much appreciated.

 

The chip just plugs in-it is under an access cover on the
ecm,fits into a plastic frame that plugs into the circuit
board.'82 ecm will work on '83 and vice-versa,different#s
and they look different(82 is bigger) but they plug in the
same and work the same(i have used both on my car,-
just to troubleshoot-never had any ecm problems.)
did have errattic operation with my'82 ESC box so i wired
in an '83 ESC box-different,minor wiring changes but works the same.DO NOT use 83-84 chip in '82 ecm or
'82 chip in 83-84 ecm, I did that and fried the chip-
whoops. When you swap chips disconnect the battery to
reduce the chance of frying the chip when it is being
swapped.

 

Easy answer is the EBL-ECM see dynamicefi.com. Flash based no chips! Note the link to speedtronics.net for the conversion to stock harness which make the ECU a plug in.