1996 5.0 vortec to 1998 5.7 vortec swap questions.!

[gerardobernal1]

So as i stated i swapped a 1996 5.0 vortec to a 1998 5.7 vortec. used the 98's pcm and plugged right in to the original wiring harness. its running fine but i do have a couple codes. one is for a o2 sensor and the other is a vacuum leak i was told. is there somethin i looked over while doin the swap? I heard something about i needed another o2? and another catalytic? Help?! Lol

 

[1997chevydriver]

So as i stated i swapped a 1996 5.0 vortec to a 1998 5.7 vortec. used the 98's pcm and plugged right in to the original wiring harness. its running fine but i do have a couple codes. one is for a o2 sensor and the other is a vacuum leak i was told. is there somethin i looked over while doin the swap? I heard something about i needed another o2? and another catalytic? Help?! Lol

Most if not all vortec 5.7s had two cats and 4 o2 sensors. You will probably have to find the exhaust from motor to behind cats for the 5.7

 

[Aloicious]

the pcm pinouts for the 98's are different than the '96s. and they use a different PCM, although they are similar, just get your '96 PCM tuned for the 5.7 and use that one unless you want to weed through the harness pins and correct the pinouts

 

[gerardobernal1]

I have my original harness tho?

 

[gerardobernal1]

Ok, that pcm is long gone, can i just get one off a scrap yard truck?

 

[Aloicious]

I have my original harness tho?

harness out of a '96 or '98?

 

[gerardobernal1]

The harness is still the original, 1996.

 

[Aloicious]

yeah, then its not a simple plug and play PCM switchout...you can use a 98 PCM, but it will require you to move some pins in the PCM around, and have some things tuned out that the 96-97 years lacked which the 98 has....either way you're looking at getting a tune of some sort, the easiest route would just be to get a '96 PCM tuned for the 5.7, and plug that in, you should be able to grab any 1996 PCM from a junkyard or something to have it tuned....the 96-97 PCMs have 5 plugs on the PCM (4 larger ones and a small one), late 97-98+ have 4 (the same sized larger ones, but missing the 5th plug)...

 

[gerardobernal1]

Ok now who should i go thru for a tune? and should i do all my mods like exhaust and tranny before the tune or after?

 

[gerardobernal1]

I just bought a pcm off ebay for $45+ shipping. now how does a tune work? do i send the pcm in or? Im pretty new at this so don't laugh at me lol