Ls swap

[smsheridan1980]

Hello quick question I’m doing a 5.3l swap on my 97 obs im wanting to know if I can use the factory pcm to control the transmission and use the new pcm for the motor is this possible I got a ls stand alone harness but it’s not shifting out of 2nd gear when I hook up the old wires from the original truck harness it shifts but will not go into overdrive help please.

 

[yevgenievich]

which transmission ? I would fix the wiring and program to work correctly with the new ecm

 

[smsheridan1980]

4l60e

 

[yevgenievich]

What are the details on new harness and ecu? Is it set up for 4l60e?

 

[smsheridan1980]

Yes it is and it has the cats delete and all that I think it might be going in to limp mode so I am going to try and reset it but I don’t have the oil pressure hooked up to the new harness it has the old one plugged into it so the gauge would work I went and got a after market gauge to install so I can use the new harness plug on the gauge I was going to put a tee in so I can run the after market gauge and the other one for the computer at the same time not sure if that will work and I am going to try and reset the trans control with the steps of the gas peddle and turning the ignition on.

 

[smsheridan1980]

I bought the truck with the swap started but it’s not shifting correctly but I have done some more research on the wiring and at first I thought the transmission was just bad so I was asking about the pcms because i wasn’t sure if it was possible so now I’m going to rewrite the transmission harness to the new pcm and see if that takes care of it

 

[yevgenievich]

With so many unknowns, start with verification on wiring, then ecm. Oil pressure wiring is not necessary to go to ecm

 

[smsheridan1980]

Ok so should I hook up the transmission to the ls harness it has it just not hooked up thanks for the help.

 

[yevgenievich]

Would need to start with a pinout for your ecm, then trace wires for the transmission. And/or verify ecm is programmed correctly

 

[smsheridan1980]

Ok thanks