Swaping to newer flex fuel engine

[douglasnc]

Hi again, Was woundering why a 2001 flex fuel 4.0 sohc wouldn't interchange in place of a 1999 4.0 sohc engine..Have a chance to buy a low mileage 2001. Is the pcm set up different and need to be swaped? Will it not work with the 99 transmission? At a glance they look the same as mine..Would like to swap engines, and work on old engine as I had the time and money as a spare maybe...Thanks

 

[ExcelDominus]

I'm kinda interested as well. Although should mine ever die I wanna change it out an eco boost. Not sure how to ask my question but I would like to know if there is a link/pdf/.doc to read about what currently is interchangable or how to find/search for a mod kit if they exist.

 

[imp]

Hi again, Was woundering why a 2001 flex fuel 4.0 sohc wouldn't interchange in place of a 1999 4.0 sohc engine..Have a chance to buy a low mileage 2001. Is the pcm set up different and need to be swaped? Will it not work with the 99 transmission? At a glance they look the same as mine..Would like to swap engines, and work on old engine as I had the time and money as a spare maybe...Thanks

Look at this situation like this: The flex-fuel engine will run on 100% gasoline as well as a MIX of gasoline and alcohol, starting with 99% gas, and going on up to what, 15% gas/85% alky?

If the computer is able to handle that, why would a different engine than the original, assuming injectors, etc. were identical (or use them off the old engine, along with the PCM, if you like) not run just as well? Unless I'm missing some significant point here, which if that's the case, I hope someone knowledgeable sets me straight! imp

 

[douglasnc]

Thats what I was thinking also.I;m thinking besides making sure that the two engines both came from 2WD or 4WD respestfuly,The only other possible differences might be the intake or maybe the pcm needing swaping.Neither swap would be a big deal if you'r already able to swap an engine. Flex fuel engines are later engines with all the bugs removed that plaged the earlier 4.0sohc,so i'd love to hear from some of the pro's here on this topic.

 

[Carguy3J]

I'm not sure, but I would suspect that the intake, injectors/fuel rails, various sensors, and parts of the wiring harness are different. The PCM is definitely different, as would be the fuel lines and related items (different materials to withstand the ethanol, which "eats" certain rubbers/plastics found in older/non-flex-fuel vehicles(s)/systems. It is also plausible that the flex fuel motor might have a different cam, to go along with a re-calibrated PCM. However, I'm just speculating on that. It could very well be the same cams, and probably is.

Provided that the cam(s) and other engine internals are the same, which I think they are, you should be able to use the flex-fuel long block, minus the intake and fuel delivery systems, and sensors. In other words, swap all the sensors, intake plenum, injectors,etc... from the old motor onto the new.

 

[2000StreetRod]

No actual experience

While I have no actual experience with flexfuel Ford engines I've read that they have a means of determining the alcohol content of the fuel. Engines after 2000 use the O2 sensors and the PCM to estimate the content. The optimum A/F ratio for E85 is 9.8:1 vs 14.7:1 for unleaded fuel. The PCM adjusts the fuel injector pulse width based on the determined alcohol content.

Since alcohol is corrosive all seals in the fuel system from tank to injectors must be resistant to alcohol corrosion. Since alcohol as a fuel exhibits cold starting problems many blocks to be operated in the North will have a block heater installed. E85 is switched to E70 at the pumps in the winter in cold areas.

In theory, I agree with Carguy3J that if you use just the flexfuel long block there should be no problem. It only costs Ford a small amount ($100-$200) more to manufacture a flexfuel vehicle. Since E85 vehicles pollute less Ford probably receives a federal emissions credit to offset the rest of their unleaded fuel vehicles. In practice, since most of the flexfuel vehicles end up burning unleaded fuel there is no significant emissions reduction.