I have the wiring harness, ecu, motor mount brackets, and radiator.
What do I need and what problems will I endure.

 

You have some added challenges since you have an OBD-II computer and associated wiring.

The problem becomes dealing with the DPFE (flow-based) EGR system and the Mis-fire detector that computer is expecting to see. Your 1994 5.8L engine has none of those. The Mis-Fire detector could probably be omitted, but the DPFE feedback system will need to be sourced.

 

I'll have these problems even with the whole harness from under the 5.8's hood and the ecu from the 5.8 as well?

 

IIRC, there are difference in the main cab connectors too, so it's not just as simple as swapping the entire underhood harness.

Also if your state has emissions checks, your truck will fail since they can no longer plug it in.

 

I did misread your first post. All the wiring and computer are from the '94 donor, correct? If so the EGR issue is moot.

Leadhead hit the biggest obstacle, i.e. the connectors to the cab are not always pinned the same between model years. Sometimes they change between engines.

You need EVTM diagrams for both trucks to see how you can make them work.

 

Just out of curiosity can I delete my smog pump or will I run into problems there?

 

No issues there if done correctly. Leave the TAB/TAD solenoids electrically connected, remove the plumbing, then plug the ports on the back of the heads.

There were various belt routing schemes used on these trucks so getting a shorter belt to work may involve some trial and error. The key is getting enough belt wrap around the alternator and water pump.

 

I appreciate the help, I'll let you know what happens. I'm coming to a close. I'm guessing this is where the troubleshooting starts. Lol I'm sure there will be some more questions.

 

Subscribing.

This is going to be truly interesting & I wish you the best of luck.

For simplicity's sake (& we're all on the same page), You're turning a 96/4.9 OBDII into a 94/5.8 OBDI. Right?

I'd second getting the 2 relevant EVTMs.

Think I would change the 4.9 harness & computer to a 96/5.0 mass-air. Just sayin'...

 

I got antici and bought the motor and trans for $1000. It came with anything I needed. Which is sweet, cuz I keep coming back to the yard and the guy just tells me to take whatever I need. On top of that if I need a part pulled, they pull it. But yeah I'm going from a 96 4.9 mr5 to a 93 5.8 automatic with a 94 cpu and harness from where I've pulled a zf5.
I think I'm going to delete the smog and the cats and true dual it out to the back. God typing this out makes it sound so much more crazy. Lol

 

I finished my 4.9L to 5.0L swap a couple of months ago and can see a couple of issues you're going to run into from your list of parts. If you're going to an automatic then the ZF5 harness and the ECM isn't going to play nice with the auto. It may work with a C6 or old AOD, but if you're using an E4OD you need a different harness and ECM.

Having wiring diagrams of both systems is a must. It isn't going to be plug and play - I had to chop out a ton of stuff from my donor harness, map out the connections, and graft in appropriate connectors to tie it in to the harness. If I were you, I'd find an appropriate 5.8L harness and ECM from a '96 and change whatever is needed to make all the connections to the engine.

As for crazy - the deeper I got into mine the more I realized it was far more complicated than I anticipated. The engine harness took me 2 weeks working weekends and after work to get right.

 

that's is like my dream is to a v8 swap but i wanna someday swap a powerstroke into my 1991

 

I have the ECM and the wiring harness from a 5.8 that the ZF5 came off of.

 

Still a little unclear of the intended swap...'94 5.8 with what transmission is going in the truck?

 

I'm putting a zf5 in it. And to f150 rebel i've thought of the same thing with a powerstroke swap but the wheelbearings I don't think would take it.