4.3 vortec swap question
 

i have the 96-97 version ... i know that the second gens had like 3 different motors ... my question is... can i take a motor out of lets say the 98 and drop it into my 96 without having to change the ECU fuel pump and everything else ... or do i have to change all this and waste time lol

98 engine will go right in, but you need to use the PCM and the engine wiring harness from the 98 too. The 96 & 97 had 4 oxygen sensors, 98 only has 3.

I thought it was that some of the sensors were different.

so i dont need to change the ECU ... but i do need the wiring harness?? ... what would i do about the O2 sensors??

Crankshaft position sensor data is unique for each engine. Whatever engine you use, you need to use the PCM from that exact engine, or have the relearn done to the PCM. If you change from 96-97 to 98, you need to use the engine wiring harness AND the PCM from the 98 engine.

EDIT: If you use the Y pipe from the 96-97, don't connect B1S2 sensor, just leave the old one in there not connected to anything.

https://blazerforum.com/forum/attach...ine=1369960212

ok i understand now... but the 98 harness will plug right into my 96 ECU?

i feel like an idiot but iv never delt with engine swaps or even had a motor seize up ... this is all new to me ... i dont want to piss ya off by askin these questions so bear with me please lol

Don't use the 96 PCM with the 98 engine. Keep the 98 engine and 98 PCM together. That way you will not have to reprogram anything.

so is the PCM and the ECU the same thing?? lol im so stupid

This is how you learn, by asking questions ;) ECM, (electronic control module) is "old school" technology and uses a chip. A PCM, (powertrain control module) is programmed to each individual vehicle depending on how it was originally equipped: Engine, transmission, rear axle gear ratio, tire size, transfer case, etc, etc.

would this also be true if you only need to use the block?