I had a 2002 4.6 4wd, swapped the 4.6 to a 5.4. I guess the computer is still thinking it's a 4.6, since the firing order is not the same what do i do to reset the computer so that it fire in the correct order? Or is the order the same? What else would u need to adjust when swapping these two engines? Thanks

 

It's the same firing order. You don't say what year the 5.4 is that you put in. That matters...

 

5.4 came from same exact year 2002. Forgot to include instead of the v6 now its v8 and the firing order for the v6 is 1-4-2-5-3-6 and the v8 is 1-3-7-2-6-5-4-8 at least that is what my Chilton book tells me.

 

Do you have the 5.4 donor truck computer and wiring harnesses?

 

Not on the truck I can get it though. It was just in bad shape so I used the old one. Changed all connectors though before I put it on.
Or did I waste my time doing that.

 

The V6 computer does not have enough outputs to fire the V8 coils.
The sensors are not consistent either.
The programming for stuff like ignition advance curves, fuel delivery, etc. are not the same. The V6 computer will simply not work.

White89gt and a couple of others on here can provide much more info than I can but without the proper computer and wiring harness it will not be a good swap.

 

Correct, you need the doner since you changed platforms. That's a lot of work. You went from Essex to Modular, lots more work.

 

So now what do I do it's already swapped. Can I get a new computer? Where is this computer located? At first after putting the v8 in I ran on 6 cylinders for a while Can I go back to that? Would that be better? I'm assuming this is expensive but I'm already half way there right?

 

So, you swapped from a 4.2 v6 or a 4.6 v8 to a 5.4...which one was it? You mention both and that muddies the water up here.

You would still want a 5.4 computer even swapping from a 4.6. That 0.8 liters does make a difference in how things run.

 

To have a running engine you will need the PCM (computer) and the PCM to engine wiring harness.
The PCM is on the right rear side of the engine compartment.



It would be best if you can get the one from the engine donor vehicle.

Also, what did you do with the trans? One from old truck or reuse what you had?

I gotta get to work so someone else will need to help you for a bit.