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?

The short answer is no;) Keep in mind that the crankshaft position sensor is attached to the block. If it is moved, removed, replaced, or disturbed in any way, the crankshaft position sensor relearn is mandatory. It is done with a high $ scan tool capable of initiating it. As far as the PCM is concerned, swapping the block would qualify as replacing the sensor and the relearn is necessary.

ok got ya... so all i need is PCM and wiring harness... if i bought the motor without all that then what do i do

Go buy it somewhere, you need it.

if i bought a new PCM from like Advanced Auto id still need to program it tho right?? or would it teach itself

It would need to be programmed, AND the crankshaft position sensor relearn would need to be done.... at a GM dealer.

and thats gonna be a big F you to my wallet lol... i went to get a key made for my saturn w/out the chip... they charged $75... needless to say i walked out of there with no new key

I believe captain hook to be very knowledgeable when it comes to these Blazers. however I disagree with him on the swap, I truly believe it is able to be done with the factory computer in the 97. I however have never done it but will be doing it this summer. and I will let everyone know if it works.

The '98 engine should start and run with the '97 PCM, but, the crankshaft position sensor relearn must be performed. If not, the PCM will use the data from the last relearn, which is now incorrect with a different engine. The PCM uses the data for making every calculation and adjustment to injector timing, ignition timing, injector pulse width, EGR, idle speed, cylinder misfire detection and identification, etc etc, the relearn data must be correct for the engine to run properly.

Ok so I'm getting a 2000 model motor out of a wrecked blazer with everything included .... now I'm starting to get mine prepared to be pulled and have no clue what I'm doing lol... I want to learn but this is harder than I expected

Seems like 2000 has a secondary air pump and your 96 does not. You'll get a service engine light for it.

Ha I honestly think that's burnt out... because I never got one... nor do I ever see it