Are you really suggesting that all that mixing-n-matching would be easier for a beginner to understand than simply taking something that WORKS & putting it all into another vehicle? I don't think so.If you're advocating ease for a beginner, who cares about upgrades? The swap in itself is the ultimate upgrade. And I don't think you can find more support than there is for a stock '99 Explorer. Any shop in the country (probably on the PLANET) can diagnose/repair/find parts for one, so that's easily more support than anything you cobble together.I disagree. The more you mix crap up the more work they are to make work & keep working.You think it works better than the stock PCM? Again: I disagree. I don't see any big rush of stock Ex/Mtnr owners to buy an aftermarket controller.
Here's the straight fact: a stock Explorer powertrain works. Well. Keep it together & working like it was designed to, and you'll have MANY miles of easy driving ahead of you, even if it's inside an eB skin. And that's the easiest way to make it work - as a complete system. Why? Because it's already designed & built to work that way. If Frank could have afforded a wrecked '99 Ex back in '99 when we built his truck, that's what I'd have put in his. But the '88 F150 stuff in it now works better than we ever expected.
Have you actually swapped an OBDII system before? There are only a handful of OBDII swaps into early Broncos. None were cookie cutter installs. There is a great post regarding an OBD-II Explorer swap on this site. He had it out and running in on the floor in a few hours. but there are countless little bugs to chase out. PATS, vehicle speed, etc. Not many engine swapers keep an ociliscope around to track vehicle speed pulses. Again not the easiest way. Even the above mentioned swap still took a cal editor if I remember right to get the computer happy.
As far as using a stock engine computer to run the transmission, yes it can be done. But keep in mind that the stock Explorer has NO Lo range. By using a dedicated transmission controller you can set your own programming to match the driving needs of low range.
I have done OBD-II swaps in newer vehicles. Swapping between 2 like vehicles works out fairly good. I have done some that have been in SEMA before. But there is so much where the engine controller interfaces deep into the body eletrical system. Stock gas gauge not working, you have a check engine light. Lots of little things like that.
I am sure that in a few years when the OBDII system gets more understood by the weekend swapper then it will be easier. But you also need to remember that the Explorer computer isn't the same for those 6 years they made the 5.0 Explorer. It changed, often. There are usally at least 2 calibrations or more per model year. So what it takes to swap an early '98 motor will all likely be different then what it takes to swap a late '98 motor.
You state that it is best to take a whole running package and put it in. Yes, that is generally the case. But the whole package doesn't drop in that easily. The mix and match is a common and proven combonation. Until you start coming up with fixes for the problems you are going to have during the swap you are just bench swapping. Have you done an OBDII swap before, into an older chassis? How deep have you researched that it will just work with so much of the rest of the vehicle not there? Got a simpler idea for you, just put a Bronco body on an Explorer. That is all likely easier then swapping all the little parts to make the Explorer work. For those of you who fully understand the EEC-V computer and all the sensors, great, go for it. but it isn't the simplist thing for the shade tree mechanic that struggles with points and a carburator to figure out. The mix of parts I listed are a proven combonation that have tons of support behind it. The mustang based EFI is fairly easy to work on, all you really need is a digital meter. The OBDII can pull data through the service port but you need much more expensive and elaborate equipment to do it.
If someone gets lost doing a mustang based engine swap, this site can help.
IF someone gets lost doing an OBDII swap, there are a couple that might be able to help but they are a lot more on there own.