Best Way to Change Firing Order

[RADustin]

Working on a non-ls platform that has a 24x and 1x sensors added along with 4L60e and DBW. PCM is 0411. Keeping coil on plug.

The engine/cam is the older genI firing order, 18436572.

What is the best way to change the firing order in the PCM/harness to match this?

Are harness mods needed? Or can it be done all in programming?

I found this link on assignments-
http://www.lsenginediy.com/gm-gen-iii-ls-pcmecm-change-firing-order/

but it is confusing as it more pertains to making the fuel trims work. I want these work, but I also want to make sure the ignition and fuel injectors are correct.

Do I swap wires at PCM OR plugs with 4,3 and 7,2 respectively at both the coils and the injectors? Then change(program) the injector assignment table to adjust the banks, as the 5.7L van tune would have? or is there a way to do the swap completely in programing?


Appreciate any help.

[Tom B.]

Swap the wires for the coils at the PCM and change the injector bank assignment in the software. There is no other way to change the firing order.

[Highlander]

There is a firing order on the ECU for misfire purposes, so you will need to keep into account that information through out the scanner display.

[Tom B.]

Good point. Although I haven't had any misfires, I will put that on a post it note so I don't chase the wrong cylinder.