Can I swap my 2007 f150 5.4 engine for a 2007 f150 5.4 flex fuel engine? If so, what else would I need to change on my f150 to make the flex fuel engine work properly?

 

All the info I got with my 07 5.4 says flex fuel. Even on the gas filler door. Why would want to switch to a fuel that gives lower fuel economy?

 

I want to purchase a wreck/salvaged F150 to obtain another 5.4 engine. This seems to cheaper than purchasing just used stand alone engine. 99% of the 2007 f150 appear to be flex fuel trucks. I understand that gas engine gives better mileage.

 

I would think you would need to do one of two things. Either swap the engine and PCM together, or get your existing PCM flashed after the engine swap. While the only real difference between the two should be parts that won't be destroyed by the alcohol, I'm sure timing (at the very least) would be different as well.
Alternatively, I bet you can just install the flex fuel engine and never run anything but gas in it without issue.

 

Hey wrvond, thanks for the info. That seems to make sense. Hopefully more people will weigh in with more of the same.

 

I've been pondering on the potential PCM issue.
There's nothing the operator has to do in order to switch between gas and E85 (or E10 for that matter). So how does the PCM know you are running E85? The answer is, it doesn't know and doesn't care. It simply responds to the exhaust gasses and adjusts the timing and such accordingly. In other words, I don't think you'd have to do anything to the PCM you wouldn't have to do if installing a brand new engine.

 

Yes it's true the vehicle doesn't know if there's gas or E85.

However...... the real issue is whether or not the PCM calibration even has the proper tables and maps to accommodate the change in fuel. Vehicles that are not E85 capable do not have the calibration programming needed to make such large changes in how the fuel is delivered and ignited.

So even if the motor itself is technically capable of running E85, the PCM may not be able to adjust enough to run properly, and could actually cause engine damage because of improper fueling/timing.

 

I don't see why you'd need a whole engine. I think the fuel system and PCM would be the only differences

Some vehicles use a sensor in the tank to calculate ethanol percentage. No clue if the F150 uses the same.

 

Good point. Texasteddy could purchase the salvage motor and simply use it as a short block.
Block and heads are just about the only things I can see needing. I'd probably reuse plenum, throttle body, alternator, power steering, and such, replacing the water pump and taking the opportunity to replace oil pump and timing components with high volume parts.
PCM swapping/flashing would be a non issue.

 

Best thing to do is buy a flex fuel truck. the fuel system is made for alcohol. the Non flex isn't.

 

I could be wrong, but I don't think he's asking about running E85 in the truck. He has a 2007 5.4 that happened not to be equipped with the flex fuel option. It's cheaper for him to buy a wrecked truck and take it's 5.4 for his truck, than it is to buy a used unit somewhere. Problem is, all the wrecks are 5.4 FFV models.

That being said, I do believe the programming of the PCM's is different in the fact that the FFV has different maps to support from 0 to 85% and everything in between ethanol content. To be safe, taking the PCM from the donor truck would be a good idea. I do believe you would be fine with the FFV engine on your stock PCM as long as you ran straight gas and never tried FFV, but I'm not fully convinced that everything between the two models of engines are the same. I would think the injectors would be different, and maybe a different set of controls because of that.

 

Just curious if this swap was done or not I have 05 lariat 5.4 and looking at 07 5.4 flex for new engine I don't care for the flex gas as they don't offer it up here I just need new motor and was wondering if I just changed fuel rail and injectors if it would plug and play thanks for any help this is the only forum on 3 different sites that gets close to what I want to do. Thanks again

 

Hi. I know it a couple years later and wiring if this swap was done successfully and what was involved.
I'm facing the same problem. Mine is a late 08 with the upgraded 5.4 so I need to replace with a late 08 or 09 10 engine but the only ones to be found are flex and I just want to run in a regular fuel .

 

 

There are some fuel system changes, but there is no sensor. The PCM infers the percentage of E85 based on input from the oxygen sensor.