1998 F150 4.6 to 2002 5.4 swap
Kept the 98 PCM and Coil Packs, Extended IAC, Tapped H2O Sensor
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- Initial start up; idle was PERFECT only ran for 5 minutes when I ran out of fuel.
- Everything was connected except exhaust (straight header)
- After pumping 2 gallons of fuel and driving it down the block it slowly got rougher, then stalled.
- I bolted up the new catback with all 4 - O2 Sensors
When I went back to try and start it, it now seem to be missing an not wanting to idle, doesnt seem to be running on all 8 cylinder either..
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MY PROCESS OF ELIMINATION:
1)Fuel Filter Replacement
2)Checked Fuel was pumping thru new fuel filter
3)Checked Fuel Pressure 40psi
4)Checked Firing Order and Coil Packs
5)Checked Sparkplugs All 8 Spark
6)Ran Diagnostic Code Scanner (0 codes stored) no codes
7)Checked Fuel Injectors all hold and spray evenly

---NO CHANGE
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can anyone point me to the next step?

http://www.youtube.com/watch?v=eIvfdHmYd2Q

 

In order to get more info on what may or may not be going on, you need to use a good scanner to look at the operating parameters and any codes set.
Otherwise you are outside the system looking in and can't see anything.
Have you checked the fuel pressure and sure there is no water in the gas?
It's a good sign the motor initally rans smooth.
Good luck.

 

I own a Diagnostic Code Scanner.. No Stored Codes
psi 40 hold 40psi ... presures good

 

Now you get your chance to play 'doctor' and search for the issue.
Starting with an overview of how the engine control works,
At crank over time, the CPS signals the PCM to start the fuel pump and provides rotation speed and cylinder position reference info to the PCM.
The cam sensor provides the PCM with rotation timing from the camshafts and reference for fuel injection and fire order timing.
The Mass Air meter provides airflow signal to the PCM.
the TPS provides the throttle angle load info.
The IAC is controlled by the PCM to regulate IDLE speed and provide extra air at cold start and high idle control.
The Ox sensors take over fuel control about 45 seconds after the motor begins to run from cold start.
CHT sensor provided cold start value to set fuel richness then monitors after that for issues of out of limit temperatures.
The IAT also refers air temperatures to the PCM.
. I don't think anyone can tell you just what your issue is.
So far there is nothing to go on.
You had your hand in all these areas doing the swap.
When you get it running again, use that nice scanner and look at the operating parameter for anything out of the normal limits.
Good luck.

 

Did you reuse the 4.6 sensors and actuators? IAC, MAF, IAT, TPS ect. Are all the connectors plugged in? Any air leaks between the MAF and Throttle Body?

 

The motor came complete from throttle body to catback exhaust.. all 2002 sensors plugged right in.. the only one I added from the 4.6 motor was the Intake value thats was located in a plastic container under the aluminum intake manifold.

received some posts of "water in the tank.. fuel sits on water?!?"
anyone concour? running out of options might drop fuel tank and clean it out today..

 

Just replaced the fuel tank.. no change..

out of options.. hate to give up..
FOR SALE 1998 F150 with 2002 5.4
not running!
$3100.00 obo

 

Use all of the 4.6 sensors and actuators that you can. They were known to work. Still getting spark? Did any fuses blow?

 

RE:
The lead frame harness in the trans is quite easty to replace. You just need a pick and a scredriver to unseat the connectors. If you find it still fails then go ahead and replace the EPC and solenoid pack

Anyone find any truth to this? is this a possibility?

 

Comment: Seems the whole issue as you discribe can't run like that without setting a/some trouble codes.
The PCM looks at and monitors a lot operations.
I think you are missing an issue that if affecting more than one item.
As an example; there is 'one' fuse' that if blown will set a bunch of codes that would seem to be unrelated until you look them up, put them in groups and look at the wiring for power feed and see a single fuse powers a lot of different operations.
This is an example of what happens when one OX sensor heater lead shorts to ground and blows that fuse.
It blows a fuse that prevents the transmission solenoids from operating, convertor clutch won't operate, EVAP system fault, A/C wide open throttle relay won't work etc.
In this example, one fuse can create 8 to 10 seemingly unrelated codes until you understand the relationship the fuse has to all the areas the codes are referring to.
This blown fuse will not allow the transmission to engage and feels like the motor has an issue. What may be tricky is the trans will still work in reverse because reverse does not depend much on solenoid operation.
Some of the best shops can miss it or take a long time before they get wise to the cause and effect.
Good luck.

 

Did you do a compression check on all the cylinders?
After my swap I I had a vac line come loose and it messed up the idle a lot.
Then i ended up with a tulip'd valve, so bad compression on one cylinder, missed too.

Fixed that and bought a custom tune. Then it ran great. Sold the truck and new owner didn't want the tuner...go figure.

 

My battery died from cranking it so much..
I disconnected my POS terminal and started to charge my battery I reconnected the battery and set the charger to "12v Start" and the truck started up fine.. drove it around and seemed perfect 1hr later it slowly started to get rough and a little longer I heard that missing sound again.. I parked it and now I'm back where I started..

 

Check your battery voltage. If it gets too low, about 10.5 v, it will not properly run the PCM and the engine will sputter and die.

 

i agree with jmc, sounds like the alternator isnt working correctly. low voltage on newer vehicles means alot( IN A BAD WAY)