bigsapper

iTrader: (2)

I want to run e85

NKPPhil

It'll make more power.

62nalide

iTrader: (1)

How hard could it be to just pump E85? Most 5th gen camaros aren't flex fuel but the stock pump and injectors can take E85 like nothing.

bigsapper

iTrader: (2)

I'm pretty sure the tuning is different along with the fuel type sensor.

01WS6/tamu

iTrader: (36)

Tuning is different but the wideband 02's are what the pcm uses to determine what fuel is in the tank. I've never done it but based of my understanding of the electronics if you build a tune it should run just fine.

The longeivity of pump and injectors lines etc may be a issue but doubtful as most everything is built to run corn gas these day's in some capacity or another.

kyle's v

iTrader: (4)

So how long before GM announces IF this will be somewhat of a production truck??

I seen a ford Tremor at a dealer lot earlier this week.

NKPPhil

Yes the tune is different, and your ECM decides which tune to use. Here's what they were saying in 2011 about "how it knows," one of the guys posted this back then:

E85 compatible vehicles no longer use an alcohol sensor to determine and adjust for the alcohol content of the fuel in the tank. Instead, the vehicle calculates the alcohol content of the fuel through measured adjustments.

The ethanol calculation occurs with the engine running after a refueling event has been detected via a measured change in the fuel level sender output. The virtual flex fuel sensor (V-FFS) algorithm temporarily closes the canister purge valve for a few seconds and monitors information from the closed loop fuel trim system to calculate the ethanol content. This logic executes several times until the ethanol calculation is deemed to be stable. This may take several minutes under low fuel flow conditions such as idle, or a shorter time during higher fuel flow, off-idle conditions.

Air-fuel ratios and the corresponding ethanol percentage are updated following each purge-off sequence. The fuel alcohol content percentage value can be read on a scan tool.

When an E85 compatible vehicle is built, an ECM or PCM replaced, or if the learned alcohol content has been reset with a scan tool the fuel system will need to contain ASTM gasoline with 10 percent or less ethanol content.

A minimum of 11 liters (3 gallons) must be put in the tank in order for the vehicle to recognize a re-fueling event. It is not necessary to turn the ignition OFF in order to have the re-fueling event recognized, however local safety regulations should be followed.

After the re-fueling event, the system registers the amount of fuel that was added, relative to the amount that was in the tank. Reading fuel trim and O2 sensor activity, the system determines if the fuel added was either ASTM Gasoline or ASTM E85. Based on that determination, the system adjusts to the expected alcohol mix in the fuel tank, and then the fuel trim and O2 sensor activity fine tunes the adjustments. The system must remain in closed loop in order for this adjustment to occur. Numerous short trips after switching from gasoline to E85, or E85 to gasoline, can result in driveability symptoms due to the inability of the system to adjust for fuel composition by not attaining closed loop operation.

bigsapper

iTrader: (2)

Awesome info! Thanks for posting that.

So my take away is that E85 compatibility is actually now part of the ECM programming.


In any event, I'm not going to wait around 3 months to see if Chevy will (not) offer the 6.2 in the RCSB, which is all anyone is looking for anyway.

I'll just order my 5.3 now and put a blower on it.

Koots

The fact you can tune for e85 is nice, but does GM equip the fuel system to handle it? I'm sure they wouldn't waste time installing regular rubber o-rings, hoses and seals, but it's something that is very important for most alternative fuels.

NKPPhil

E85 has something like thirty percent less energy by volume than the usual E10 that's sold as "gasoline" these days - so an engine needs a greater volume of fuel per x amount of air in order to run. I have to wonder if something in the new DI 6.2 fuel system is the limiting factor that kept them from making it E85 capable. Anybody have any ideas?