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Discussion Starter #1
I have my engine and trans out of my 95 Bird and just about ready to go back in and decided to change out the pcm again. I currently have a 97 Mark VIII pcm with a tune and I am thinking of changing it over to an 05 pcm for tune ability as I want to run E85 and do away with my Alky system.
Has anyone done this yet??
I really didn't see any advantage to the Mark VIII pcm other than a good starting point for the DOHC .
Since I have the engine and trans out and both freshened up I was just thinking it would be nice to run a late model PCM for ease of tuning and probably sell off the Mark VIII pcm and the Jet chip I got for it years ago. I will probably keep the X4 for another car.

Or am I looking at this wrong and is there an easy way to run E85 off and on..
 

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Try using a QuarterHorse instead.

Eight banks, on the fly programmability, and deeper datalogging than the OBDII port gives.

(It's supposed to fit EEC IV and EEC V ECUs both; the Mark VIII is supposedly a EEC V. If it's not, then ignore this.)

RwP
 

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Changing to an 05 PCM will be very involved, for little to no gain. You will need to run the newer wiring harness as the 05+ PCM connectors are completely different. All 05+ 4.6s are drive by wire, so you would need to set that up. You will need to deal with PATS. It is a major headache for no reason. If the wiring has already been modified to run the MarkVIII PCM, stick with that. If you are going to change it to anything, just change it back to the stock 2V ECM with a tune.
 

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Discussion Starter #4
I do a lot of late model swaps mostly LS in old cars and have the tuning software available to do 05^ Fords. So was thinking the 05^ PCM would be a good platform to work off of.
My original PCM fried and I couldn't find a match to the LLX3 that was in the car. So I got one from a Mark VIII in the scrap yard. The Mark VIII was a pain to switch over to but was already good for the engine set up, and with the Jet chip ran like the original pcm. Later I got the SCT-X4 and it got better.
Now, I want the flex fuel capability of the newer pcm. That way I can do away with the Alky System and gain back some of the trunk space.
Wiring is kind of what I do so that's no biggie and I want to use the newer EV6 injectors which are much better than the EV1 we use in these engines (I think they will work fine with the old pcm but not sure, need to do more research )
 

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Flex fuel won't work without having the sensor in the tank too. With a quarterhorse, you could easily have one tune for E85, and another tune for regular gasoline though, which would accomplish the same thing, except that you would have to run the tank down to about 1/8 of a tank before switching fuels, since you wouldn't be able to accurately calculate the alcohol content, and therefore the air/fuel ratio otherwise.
 

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Discussion Starter #7
I was thinking I could run a sensor in line like the GM does. I have done a lot of E85 kits on them and it's pretty simple by just pinning a few wires in the pcm and adding the alcohol sensor in line before the fule rail.
 

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Discussion Starter #9
The flex fuel / alcohol sensor on the explorers and F 150 is on the frame rail. So I was thinking it would be a simple wire in like the GM sensor that was my thought. so a simple add on since the injectors are already larger for future boosting .
ford calls it a fuel composition sensor.
 
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