I just bought a 350 out of a 90 formula and i'm going to replace the 305 tpi out of my 88 IROC with it. I know that i need the ecm and injectors, but what do I have to do to switch from the maf to the speed density setup?

 

well, unfortuneately, i'm thinking you'll need the entire harness. The reason being while the systems are almost identical, the plug terminals that go into the ECM are in a diiferent order for the MAF TPI and the SD TPI.

Some of the repair manuals actually have the ECM plug terminals numbered with what wires go where...i'd chekc them out and make sure that you're wires are in the same order, then perhaps just splice on the few more needed for the SD setup. However, i think that you may ju be better off replacing the whole thing rather than messing with your current harness. I know this from trying to do so on my own swap (although it was NOT from MAF to SD) Even two wires that need to be changed just really screw the whole thing up.

 

i dont think...unless ur using th TPI setup off of the 90 car. instead of changing the whole tpi harness and computer,y dont u just put MAF on it instead of SD,and if the intakes are different put the intake off the 305 on the 350 and use the same computer/harness. i did this swap a while back (still MAF tho) and unfortunately i still have the 305 chip in it and it runs damn good surprisingly enough. the only difference on the intakes are the injectors,and if u had both intakes anyway,u could just swap the injectors so u would still have the right ones. i have my 305 injectors set at 45 psi on my 350.

hope this helps u

 

that's a good idea...way to minimize the swap effort. Listen to that ^ ! Haha.

 

The injectors are 22 pph for the 350. Those you keep. I believe in your 88 there is a cold start injector but I am not sure of the specs. Other than that and the intake manifold with the cold start injector, I believe the rest will swap over. Get a custom EPROM and you should be set.