Hello everybody! I’ve got a question that maybe one of y’all might know the answer to. I’ve got a 2002 F150 with a 5.4 2V engine. The Engine’s got a rod knock in it so it has to come out. I have a good running 2002 4.6 2v from a Town car. I do still have the pcm from the Town Car. I’d like to “use what I have” and drop the 4.6 into the truck. I do realize that the exhaust is a little bit wider, they both used a 4R70W so I’m good there and the oil pan is different. However, I’m concerned about the pcm’s. Since the truck originally had a 5.4, Won’t the pcm that in the truck need to be swapped to the pcm for the 4.6 so that the engine will run correctly (I know I’ll need the pats deleted- $100 on eBay/ cheaper than getting it custom tuned) or will the 5.4 pcm run the smaller 4.6? Other than what I’m aware of are there any other issues that I’ve not mentioned that I’m missing? Any help would be appreciated.
Brian

 

the 5.4 ecm will operate the 4.6

the intake manifold and such not so much, you’ll be lightyears financially ahead to just drop another 5.4 in the truck VS the cost of the 4.6 swap

 

I think the injectors for both engines are the same, but wouldn’t the 5.4 engine have a longer PWM for the 5.4 engine and possibly make a 4.6 run rich? Also, as far as cost, I’ve already got the 4.6 so there’s no additional cost.

 

I’d have to get a truck 4.6 manifold but the are about $40 and a local pick n pull that I use or is the manifold from a town car the same as a truck manifold?

 

Never mind about the manifold. It looks like the truck manifold and the car manifold have the same part nuMbers so I assume they are the same.

 

It won't run rich because the O2 sensors provide rich/lean feedback.

 

LOL


good luck

 

So the PCM for the larger displacement 5.4 won’t need to be tuned for the lower displacement 4.6? I don’t doubt you but it just seems contrary to reason that the tuning would be so similar that it would not cause issues.

 

It will run okay without a tune but a tune always helps.