4.6-5.4 conversion problem
Thread Starter
|
New User
Joined: Jan 2014
Posts: 5
Likes: 0
4.6-5.4 conversion problem
Hey guys, I bought a 99 F150 a few years ago. it originally came with the 4.6 and the previous owner dropped a 5.4 in it.
I bought it because he had nothing but problems trying to get it running, so I got a good deal on it.
I swapped the plugs, and wires, and it ran fine for about 2 years. Then it started to lose all power. It seamed like it was running on half the cylinders under a load and like it was hesitating and then all cylinders would kick in then out again, but at idol it ran smooth.
I dont think the last owner changed too many things while doing the swap. Is there a few crucial components that need to be changes also that I should look for ?
I know he hasnt changed the computer for the 5.4 thats in it now.
the truck is a 99 F150, 4x4 auto I am not sure how many km are on it at the moment, its burried in snow, but I would like to have it on the road before spring
the engine that is in it is a 5.4 2v and he told me it was from a 97 I think
thanks in advance for your help
IK
I bought it because he had nothing but problems trying to get it running, so I got a good deal on it.
I swapped the plugs, and wires, and it ran fine for about 2 years. Then it started to lose all power. It seamed like it was running on half the cylinders under a load and like it was hesitating and then all cylinders would kick in then out again, but at idol it ran smooth.
I dont think the last owner changed too many things while doing the swap. Is there a few crucial components that need to be changes also that I should look for ?
I know he hasnt changed the computer for the 5.4 thats in it now.
the truck is a 99 F150, 4x4 auto I am not sure how many km are on it at the moment, its burried in snow, but I would like to have it on the road before spring
the engine that is in it is a 5.4 2v and he told me it was from a 97 I think
thanks in advance for your help
IK
Laughing Gas
Joined: Jan 2006
Posts: 1,098
Likes: 11
From: Minnesota
There is a sensor that will pick up a cylinder head that gets too hot. When that happens it will go into limp mode to try to save itself. It will appear to idle fine though. That will toss a CEL though when it happens. I know I read someplace if that sensor gives a false reading because it is going bad, it will put the motor into limp mode. Bounce around the search feature here on like " cylinder head overheating protection sensor" or stuff like that and see what you think.
Thread Starter
|
New User
Joined: Jan 2014
Posts: 5
Likes: 0
im not sure what the IAC is
Thread Starter
|
New User
Joined: Jan 2014
Posts: 5
Likes: 0
There is a sensor that will pick up a cylinder head that gets too hot. When that happens it will go into limp mode to try to save itself. It will appear to idle fine though. That will toss a CEL though when it happens. I know I read someplace if that sensor gives a false reading because it is going bad, it will put the motor into limp mode. Bounce around the search feature here on like " cylinder head overheating protection sensor" or stuff like that and see what you think.
When I had it on the code reader, the only thing that would come up would be an O2 sensor. And I had them switched also.
I red somewhere on here a guy did a swap, and somebody suggested not to switch the computer. Should I follow that advice ? or should I get one of those performance computers for it and switch it up there ?
when it was running fine, the transmission would switch gears at a high rpm, and it grabbed hard it seemed
Trending Topics
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
You might use a Scanner on it to look at the live data as a first move otherwise your going to have to rely on luck.
The original motor used coil packs.
The 5.4 used coil over plug so you likely got half a butcher job on the harness install.
The ignition timing and fuel curves for a 4.6 are not correct for a 5.4 to begin with. There is about a 70cu inch displacement difference between the two.
Sounds to me like a case of wiring job coming apart some place losing a coil operation if that's what is actually happening.
The cylinder head temperature sensor is what puts the PCM into limp mode if the temperature goes high enough.
With a job like this anything or multiple issues could be the problem.
Until some diagnostics are done to get a lead on the issues it's only guessing.
Good luck.
The original motor used coil packs.
The 5.4 used coil over plug so you likely got half a butcher job on the harness install.
The ignition timing and fuel curves for a 4.6 are not correct for a 5.4 to begin with. There is about a 70cu inch displacement difference between the two.
Sounds to me like a case of wiring job coming apart some place losing a coil operation if that's what is actually happening.
The cylinder head temperature sensor is what puts the PCM into limp mode if the temperature goes high enough.
With a job like this anything or multiple issues could be the problem.
Until some diagnostics are done to get a lead on the issues it's only guessing.
Good luck.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
Thread
Thread Starter
Forum
Replies
Last Post
lllateralus
1997 - 2003 F150
2
Apr 5, 2005 05:14 PM