Single cam 4.6 v8 to twin cam 5.4 aust boss 260 v8 | Ford Explorer Forums - Serious Explorations

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Single cam 4.6 v8 to twin cam 5.4 aust boss 260 v8

Ausis282

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August 7, 2016
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City, State
Perth
Year, Model & Trim Level
2003 xlt v8
I recently bought a 2003 4.6 v8 XLT Explorer. Anyways bought it with a nearly stuffed engine. So had the idea to put the Australian Boss 260 double overhead cam engine into it to future proof the vehicle, as I love this vehicle and wish to keep it for the foreseeable future.

The gearbox will bolt right up, have to space the starter 10mm to match the flex plate as the 4.6 is 6 bolt the 5.4 is an 8 bolt and need to build a set of headers as its quite close on the driver’s side (right hand side here) with the steering going through. Everything else has been pretty much been a straight swap, mounts, accessories, the works.


Now to the problem, I need a wiring diagram and plug pin output input diagram for the CPU. I have a new computer and harness for the new engine but need to get everything talking to each other do not want to have half a dash working. I like my accessories and want them to continue to work.

Have found a standalone harness for the new engine which is an option.

Can anyone point me to the best threads to read on the forum?
found a thread with a code and password but its no longer working.
any help much apreciated
 



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For the wiring I would start with your existing factory engine harness and modify it to work. The main things you will have to do is extend all the ignition coil wiring and move the wire to the other side head for the cam pos sensor.

Your going to want to use your factory engine computer since it will be best at shifting your transmission and it with a few mods will start and run your new engine. Both engines basically have the exact same sensors. Your definitely going to want to tune it for the added fuel it will need.
 






Get a 2004 Explorer wiring diagram shop manual. Can be easily found used online. Will have everything you need.

Me personally, I say to hell with the stock ECU. The shift points in these cars sucks and the shifting is a whole other level of sucking... For sure get your trans tuned to actually resemble shifting and some proper shifts points. (3,000 rpm shift for light throttle take off really???)
 






The PCM controls both the engine and the transmission so in all reality your stuck with the stock PCM if you keep you factory trans. I'm pretty sure there is no stand alone 5r55 controller.

The ford EEC-V computer was far superior to mega squirt or any other stand alone computer, and it came out in like 1995. With the tuning available now on the stock PCMs through SCT or HP tuners I wouldn't see a reason to go any other route.
 






Thanks for the info guys, strangely had not considered using the stock wiring. Will have a very close look at them both in the morning.
Im pretty good mechanicaly but bit piss poor when it comes to wiring.
Cherrs for the idea's
 






You could get a 2004 Lincoln Aviator engine harness and it would would nearly be plug and play. They have the 4.6 dohc which your 5.4 is VERY similar to as in plugs and external locations. You might have to re-pin the harness to use the explorer computer or using the Lincoln computer you have to deal with pats programming. Just things to consider.
 






lol if ya have the std pcm off the Oz motor (and it was an auto i'm guessin') y'all could get a falcon semi auto shifter(tiptronic?) as well.....that'd be well different
 






You can use the stock PCM, just get a tune. You'll also need to get a performance torque converter with a different stall speed or you'll just grenade the transmission. ($300 to $900 depending on a local rebuilder or Precision.) Good news though, when you lose 1st and 2nd, the 5.4 will get you going in third.

You'll need the Explorer PCM to operate the 5r55.
There's some pretty good Mustang forums talking about this swap.
 






Well The swap is done engine in exhaust built all finished now to the tuning easy huh NOT.
Anyways got a tuning problem taken the vehicle to a locale ford performance tuner and it will not talk. The computer I mean I have had it running very poorly but running nun the less.

Does anyone know PCM strategy JEBF55V on the SCT tool Does anyone know that strategy.

It takes along time for answers here with the big tuners in the states.

Cheers for any help guys last hurdle almost there.
 






www.mosspeedshop.com has a forum section. They are pretty good about response time. As you are in Australia, you obviously won't be coming by their shop, they may still help you.

What did you do with the flex plate? Which flex plate did you use?
 






Hi i ended up using the original flex plate as once i spaced the starter it was fouling on the engine mount so out the engine came off with the plate and bolted the 2 together and drilled the 4.6 flex plate then had it balanced with a couple of un needed holes filled was quite a bit of hassle have run and reved the engine. No vibration at all but yet to see if any problems arise.
Not going to know till i get this tuning problem sorted.
 






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