F150 4.6 5.4 swap - F150online Forums

1997 - 2003 F-150

F150 4.6 5.4 swap

  #1  
Old 07-07-2015, 11:22 PM
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F150 4.6 5.4 swap

Hi I'm new to this from and I have a 2002 f150 that I have purchased from a friend. I bought the truck knowing the 4.6 was toast, bent all exhaust valves on passenger side and broken piston. I bought a good running 2001 5.4 and did the swap buy the information I have found on this form but I have run into a bit of a bind. The engine has a hard time starting and once it does start it won't idle at all I have to rev it to keep it running I have tested my tps,maf,O2 sensors ect everything is good except it is running way to rich. I know it's running way to rich because I have a live data scanner.also when I drive it I will go threw has faster then I can put it in. I have used all the 4.6 sensors the only thing I have on the motor that isn't from the 4.6 is the fuel rain, because from the 4.6 to the 5.4 the holes to bolt in the fuel rail don't line up anyone could help I would be thankful and if I left anything out ask 2x4 automatic 150000k on truck I'm stuck
 
  #2  
Old 07-08-2015, 10:59 AM
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Hi Kman - welcome to the forum.

I've moved your thread into the 97-03 truck section because I think you'll get more responses here than in the section reserved for comments about the forum itself.

I'm having trouble understanding your post, but it sounds like you are trying to marry parts like sensors from the 4.6 to the 5.4 engine? And, the only accessory you included with the 5.4 was the fuel rail? I've never done an engine swap, but I'd think you need to keep more of the 5.4 accessories with the engine you are adopting.

What about the PCM? Did you import it or are you trying to use the one that was married to the 4.6?

These are just thoughts, and they may well be off base. I'm sure there are people here who will have much better ideas than mine.

- Jack
 
  #3  
Old 07-08-2015, 12:23 PM
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Thank u and I'm having an issue with the truck idling and it's running to ritch and I'm am using the 4.6 computer and because I didn't want to switch harnesses I use all the plugs from 4.6 in one of the forms it's says to do this but I'm just having an issue with no idle and running really Rich I also used the 4.6 injectors and the 5.4 fuel rain
 
  #4  
Old 03-27-2016, 09:37 AM
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Im no pro but from what Ive read, the 5.4 computer needs to be used due to fuel trimming
 
  #5  
Old 03-29-2016, 11:06 AM
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Am i able to bolt up 4.6 headers to a 5.4
 
  #6  
Old 03-30-2016, 08:02 AM
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I believe they will, you may have an issue with the angle, this is based on this......
https://www.f150online.com/forums/ar...wap-notes.html

FYI if anyone is interested, I have a 99 5.4 PI set up with heads and intake
 

Last edited by savageautosales; 03-30-2016 at 08:03 AM. Reason: spelling
  #7  
Old 03-30-2016, 10:01 AM
JMC
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Look for an air leak between the MAF and the throttle body. If that proves fruitless look for a leak between the throttle body and the cylinder head. A leak anywhere in these areas will cause your symptoms.
 
  #8  
Old 07-13-2016, 09:57 AM
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Engine swap

Originally Posted by Kman52 View Post
Thank u and I'm having an issue with the truck idling and it's running to ritch and I'm am using the 4.6 computer and because I didn't want to switch harnesses I use all the plugs from 4.6 in one of the forms it's says to do this but I'm just having an issue with no idle and running really Rich I also used the 4.6 injectors and the 5.4 fuel rain
I did the swap myself and I used the old components from the 4.6 motor as far as sensors. They are interchangeable between 4.6 and 5.4. The engine ran really rough when I first started it up like yours. My Expy was a 4.6 2WD with the 4R75 transmission and the donor Expy was a 5.4 with the 4R100 4x4 transmission. My friend does tuning and he told me I had to get the ECM tuned which my friend did for me and the truck started right up and ran perfectly but the transmission would only stay in 2nd. My friend had to re-tune it and then it drove like was supposed to.

Basically, in your case and mines, you will need a tune for your ecm to efficiently run your engine. Make sure to mention which transmission your vehicle has because within the programming are the parameters for transmission also, despite what some say. Most 5.4 use the 4R100 transmission due to the extra power so when people program, they generally default to that unless they have your correct transmission code.

I am currently doing another swap from a 97 T bird into a 98 F-150. With that one, I shouldnt have any issues since they are both 4.6 engines. I just wanted to answer this question in case someone ever does the swap and needs an answer.
 
  #9  
Old 07-29-2017, 11:26 AM
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Hello. I have a 99 f150 with a 4.6 from a crown vic already installed. The truck came with a 4.6. The crown vic was a 98. Intākes swapped an everything. Wont run. What should i do?
 
  #10  
Old 09-23-2017, 07:42 AM
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What does it do when you try to start it??does not matter if the motor came from crown vic or not, I would think, if its a 4.6 original that 4.6 from the Vic is the same.
 
  #11  
Old 10-11-2018, 03:42 AM
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All of the above was false as far as tuning and all that other stuff. I have done a bazillion of these 4.6L to 5.4L swaps, and they all ran fine. Only known differences are some 4.6Ls use 2 temperature sensors so you can build a T or tap another hole into a water passage. And exhaust is wider on 5.4L. IAC wires will need extended since its further back on the manifold now, temperature sensors wires will need extended as well. EVERYTHING else can stay 4.6L. You DONT want to use certain 5.4L things cause your computer will want to see the sensors from the 4.6L and will be thrown off by slightly different 5.4L sensors. One big one for example, my truck ran poorly with the 5.4L mass air. Dont change them. Mixing 5.4L sensors with 4.6L computer parameters is all bad. Certain things dont matter, certain things do. It's up to you to know what you should and shouldn't use.
 
  #12  
Old 10-11-2018, 08:59 PM
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Good post PAXTON.
This is why I stayed out of. the thread that is a year old.
Those who try to become back yard engineers, only twist wrenches and forget the rest, end up with problems, then wonder why it's a problem and still not understand.
A 4.6 between a Crown Vic and an F150 is only the same displacement.
The application and the program version loaded into the computer has to be different.
The vehicle weight is different, transmission converters are different stall speed, the intake runner lengths are greatly different.
The fuel and timing maps are different per the engine application.
The shift skeds maybe a bit different.
After one makes what is considered a successful swap, is only based on satisfaction not the best performance based on the original factory build.
 


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