Also, who do you recommend sending the ECM to, to reflash for the 5.4.

 

Yes use the 4.6 harness, ignition and PCM. Any competent tuner can set you up.

 

Thanks JMC. That did the trick. I didn't get to try driving it because it blew a frickin brake line as soon as I stepped on the pedal.... :-/ tomorrow is another day. Thank you for your help though.

 

JMC. Truck is running pretty good now. I've driven it around about 75 miles. The check engine light came on and I checked it out., it's running lean bank one as I was expecting. I contacted my local ford dealer this morning about flashing the 4.6 PCM for the 5.4. They told me it would cost no more than $177. My concern is though, will this actually work or am I going to spend money to find out that it won't. Or should I just buy a tuner and have a custom tune done? I'm looking to get this done ASAP because I'm supposed to be towing a trailer 4.5 hours north next week, and I feel towing while running lean on the highway wouldn't be the smartest idea. Your input would be greatly appreciated.

 

If your Dealer can flash the PCM then I would get it done there. Although I must admit this is the first time I have ever heard of a Dealer being willing, let alone able, to do this.

 

has anyone done the swap and had this problem? the 4.6 was running fine in Dec 2012 when I initially removed it (other than a bad head gasket and no CEL codes). I reused everything except the 5.4 shortblock is from the junkyard. It will fire up and then die unless I pump the gas pedal. I can keep it on idle around 800 rpm if I continuously lightly pump the pedal slowly. If I mash it to half throttle or more, it will slowly rev while stumbling and after-firing until it gets to 2000 rpm then it smooths out and will rev instantly from 2000 to 4500, but it will die if I don't tease the pedal. No smoking, and no CEL has occurred.

 

Hi,

I have been reading this thread today and there is a ton of info. Given soome of the issues faced with swapping out the 4.6 with 5.4, wouldn't it be better to just rebuild the 4.6 with perfomance mods? Or, is it still better to just do the swap? I would think for towing purposes a motor with lots of torque would be a preferred option, along with getting away from 3:55(?) rearend ratio, and perhaps even going to a different transmission to lower the RPMs. Do they make aftermarket transmissions that would help the 4.6 in both towing ability and mpg? Changing the rearend ratio could decrease mpg but perhaps a different transmission would offset that decrease. Anyway, I was wondering if there are 4.6 mods to be done vs. swapping to a 5.4. My mechanic states it is better to stay with the same given the tweaks needed to get a 5.4 swap to work correctly immediately.

Thanks.

 

I have an 03 f150 2wd with a 4.6 auto. I have access to a wrecked 03 lightning and can get motor, trans, Ecu, and instrument cluster from it. I have been told to just get a lightning and not bother with the swap, but I l don't like the stepside bed on the lightnings and the swap would be more affordable for me. what other parts from the donor lightning would I need to make it an easier swap. Thanks for your time and consideration.

 

You should post this in the Superchargers section. Folks there would be better able to answer. I might forget an important item.

 

Thank you everyone for your assistance.

my 2 cents:

Truck started immediately. After tracing and plugging vacuum leaks, it idled and drove fine, but was lacking throttle response and midrange power. Tires would not even chirp at standing WOT punch, and was slow to build power. Passing gear punch was strong though.

So I added 75MM BBK TB, port matched the intake elbow to the TB, EGR delete, PCV delete with filtered breathers, new TPS came with TB, new IAC solenoid and a SCT X4 tuner.

I want to elaborate on the X4...
It has a 4.6, or 5.4 selection in the menu, and the 5.4, 93 octane canned tune is all you need to wake up this engine swap!!
Now it lit the tires up in 1st and continued to spin them in second until I finally let off because those 20’s are $250 each! I was hootin’ and hollerin’ during the lighting ceremony though. This is the first time my truck has spun the tires on dry pavement and I have had it for 10 years.
Obviously you will get better results with a dyno tune, but I am content with power I have now.
Here is a list of mods and work that my machine shop and I have done

Machine shop:
Block magged, decked and punched .020 over
Crank magged and polished
Heads glass beaded, decked, 3 angle valve job, new valve guides, and flowbenched after port and polish with good results.

ME:
Port match and polished the heads
Rods balanced to within 1/10th of a gram to each other
All new bearings, chains, guides, lash adjusters, tensioners, seals, etc. etc..
Cams and followers are stock.
COP’s are stock.

The truck also has K&N CAI, shorty headers, stock cats, true duals, X pipe, and 2 flowmaster 50’s

I also rebuilt the 4R70W and swapped in a low stall converter and installed a shift kit.

For all of those interested in doing this swap, don’t do what I did and just buy the 5.4 shortblock..

Here is a list of all the parts I had to modify because I reused all of my 4.6 accessories:

Fuel rail brackets
Fuel rail tubing
Throttle cable bracket
EGR tube
Trans dipstick bracket
Oil dipstick bracket
I had the timing cover from the 5.4 so I was good with all the accessories, pulleys, idler arm, rocker covers, oil pan. The cam, and crank sensor connectors from a 97 wire harness are different than my 03 wire harness. Don’t know which makes or models vary..

cheers!

 

Help I am in the middle of the swap and I cannot get the motor and tranny to go together. It is close but cannot get the torgue converter to line up with the flex plate.Any suggstions would be helpful.

 

I must have read this thread 20 times end to end over the last few months. I have a few questions still. The exhaust manifolds are different on 5.4 and 4.6 engines, which ones would fit better to the stock exhaust? I realize that modifications to the exhaust will be required but I would like to make this as painless as possible.

The 5.4 I picked up is a 1998 and has about 120K on it and there are no leaks. I have a set of PI heads and cams that I can install for more performance but I am hesitant to break open the engine since it is already in pretty nice shape. I would also need to buy a PI intake. Is the PI swap worth the expense for 25HP and 15ftlbs that I have read about?

 

I'm having a huge dilemma is there any way I can have you call me or email me direct? I have no clue what to do on the forums I can't figure it out lol

 

What do you guys think of this lightning motor for sale on eBay right now. Will it work with my 98 f150 4.6,What do you think of price. Sorry don't know how to post link but it's for sale for 5,889.00. I figure it would work from what I've read on here just wondering if it's worth it or is there a better route these days. Wanting more horse power and want to stay smog legal

 

@JMC
Ive read every single post in this thread repeatedly, and have more than one question, but my main one is this-
My lincoln Aviator has a 4.6 DOHC that is basically a 99-03 cobra engine. It needs a rebuild now though, and I was wondering which year 5.4 dohc engine would be the best swap?
As far as I know, there arent any 5.4 aviators around. Any and all help, advice, and criticism is appreciated. Im more than willing to make a build thread once I get some advice.