So in all the later model (1999+) Ford/Cummins swaps, people keep the Ford PCM to control the gauge cluster and various other Ford items (ABS? Airbags? Climate Control? I don't know what the Ford PCM has its hands in...)

I assume the Ford PCM is looking for things. In the case of an old gasser truck, the coils and injectors... In the case of an old Powerstroke truck, the Hydraulic/Electronic Unit Injectors and various sensors related to the High Pressure Oil Pump...

How do you make sure the Ford PCM isn't throwing codes left and right for all the missing parts?

 

Remove the check engine light?

 

Codes will still be there despite the missing light bulb.

 

It doesn't mater if codes are there or not the pmc isn't controlling the engine,the only time you would need to check codes is if you have an auto trans and it threw a code.

 

How would you know if it threw a code specifically for the transmission?
Without the engine, it'll have a million codes and the check engine light will be on all the time.

More specifically, if one needs to pass an emissions inspection, the engine codes are an automatic failure.

 

When you scan for codes it gives you a number.
Trans codes have a different number from engine codes

Where are you from ? I've never heard of inspection stations checking codes, besides if they're that strick they will fail you on having the wrong year and model engine in the truck anyway. So you'r sol on doing any kind of conversion.
What state or town does that so I'll know never to move there.

 

Right, but if the check engine light is on ALL THE TIME, how will I know if there's a trans code?

Some codes creep up with very little other symptoms.

Anywhere that has emissions checks OBD2 codes...
http://en.wikipedia.org/wiki/Vehicle...ns_inspections
While I have a way around it for my state, I'd hate to be barred from moving to another state because of my vehicle.

Also, it just seems ghetto rigged to me to see a Check Engine light on all the time. If I'm gonna do an engine swap, I'm gonna do it right.

Engine swaps are legal so long as you swap in a same year or newer engine than the vehicle; IE I can swap in a 2000 or newer engine into a 2000 Chassis and all emissions equipment is kept.

Because the 7.3 Powerstroke and the 5.9 Cummins don't have any emissions equipment, I'm good.