I was looking at the technical articles because I will be converting my 89 Trans Am that was originally a 305TBI to a 305 TPI, and the ECM interchange thread says all I need is a different PROM, is this right? Thanks in advance guys

 

nada, need whole computer. im sure you could write a chip for that but thats not my forte...

 

ok, figured I would need the tpi ecu, but had to check first

 

1227165 ecm for maf tpi and 1227730 for speed density. I have a hypertech for sale for the maf setup pm me if your intrested

 

You should read the repinning TBI to TPI thread in the engine swap section. It tells how to use your existing harness with the SD TPI (7730 ECM).

I just did this swap. Not too bad.

 

really? I might have to look into it, because I just got the TPI harness and ECU, but its from an 87, and I cant seem to find any write ups on a TBI to MAF TPI swap

 

change one wires location. took me all of 5 mins to do.

i would have preferred to go map btw but seeing as i {like most people in America} am broke therefore i made work what i had. i am saving up for the 411 conversion because i like the newer computer systems and reliability....

 

so was the bulkhead connector the same? I have both diagrams for the ECM connectors, but neither Alldata nor Mitchell had a bulkhead connector diagram

 

the connecter opening on body cutout on the driver's side under the passenger fender is the same shape for tbi and tpi

 

the connectors are the same but a few wires have to be swapped around. like i said fairly simple. if you go in the ltx/lsx swap section just compare the harness pinouts. i used an 89 camaro harness in my 91 bird. some stuff had to be moved. wires added/ shortened.

a member named pocket wrote up just about every article i used. also i used basics from austinthirdgen.com

 

ok cool, thanks

 

I am doing a similar swap, a 1991 RS that i purchased with a poorly swapped in 350 (no updated injectors or ECU/PROM). I have all for the MAF tpi conversion but the ECU/PROM and fuel pump. Is it easier to modify the existing TBI harness, or the TPI harness.

 

if you find the proper ecm/ prom for the engine?: maf. you need to know what the donor harness is from tho. the birds and camaro do have differences. i put a camaro harness in my bird so i had to add stuff from the tbi harness namely the vss wiring. the fan wiring is in a different location. i had to move that wire from the fuse box to the ecm harness. i myself dont have the 9th injector so i used an existing wiring. the crank wire goes from the fuse box to the ecm plug c207. i just moved the location in the connectors for it. not hard. it sounds like alot of work but its not if you have the printouts of all the harnesses and look at the different locations. i highlighted what needed to be changed with the appropriate pins to swap. look for the c100 and c207 connector pinouts for the 2 harness types.