Can anyone explain how the new 5.4 compensates for E85 (or any blend for that matter)?

I have made a couple assumptions. Please let me know if either of these are incorrect...

1) The EFI adjusts very frequently for a blend. So if the fuel in the line was E10, and you filled up with E85, once the "new" fuel started burning, sensors would immediately detect this and adjust appropriately.

2) If I take price/mileage out of the picture, the performance increase while pulling a trailer in the mountains would be a welcome addition, and used rarely would not affect the longevity of my engine.

OK - let me hear it...

 

I believe there is a sensor in the fuel line that senses how much ethanol is in your fuel.

 

yep, but it's in the tank...it's a big, ***** looking thing.

 

[quote=it's a big, ***** looking thing.[/quote]

so theoretically, if you switched from E10 to E85 when the tank was empty, you'd start it back up and the sensor would detect an 85% alc mixture. So wouldn't it run like crap for a couple minutes until the E85 actually got to the motor?

Just trying to understand how this stuff works a little better...

 

No, it doesn't. I have run E85 a few times, and my Edge runs better on it because the octane is so high. You're supposed to be run the tank under half before filling it with E85 and vice-versa. Mine's a flex fuel.

 

I've also heard that you're supposed to run under 1/2 before switching. Not sure why that is, if its supposed to be able to handle any blend from 0-85% alc.

Thanks for the info!

 

It can. I did it several times before I read the book...oops. I'm not sure it can sense, say, E29 or E41...It's closer to either normal E10 or E85 for the PCM and timing settings. Like when the sensor senses an abnormal amount of Ethanol, it sets the timing for E85. Chevy's the same.

 

at a certain threshold value, the PCM swaps between the E-85 fuel maps and the normal 87 fuel map.

Sorry, wish I could tell you that value. per the manual though, you are supposed to be at least under 1/2 tank before changing from 87 octane or E-85 octane. They suggest you be closer to Empty though, and to stick to that type.

Don't swap between the 2 different fuel types ***** nilly. Pick one and stay there for a few tanks. Indescriminate swapping is bad for the whole setup.



I ran E-85 on my FFV 2006 F-150. Only a few times to try it out, then never tried it again. The swap is seamless. With stock tuning, you would never know if there was 87 or E-85 in the tank. The only indicator is the crappy mileage on the E-85.



Now concerning MPG's. With 87 "unleaded" my truck got great mileage. With 87 "E-10 blend" I usually lost 1-2 mpgs...usually winter. And with E-85, I lost at least 5 mpg highway. Usually closer to 7 mpg loss though.


E-85 is utterly worthless IMO. Do some comparisons and I believe you'll shortly believe the same way. You need at least a $1.00 difference in price for it to resemble being economical to run. Between the lower MPG's and the increased Maintenance Schedule...I never ran it after about 3 tanks. Waste of my $$$$ and time

 

Ahh - so it really has a "one or the other" PCM setting, rather than a dynamic "adjust it precisely" setting.

Now it makes sense why they say to use one or the other, and not go back and forth all the time.

That kind of sums it up for me; if you're the type of person that wants to run E85 all the time, it will allow you to do that. But I'm not one of those folks, so I'll just stick to good ol' gasoline...