Run a tank of E85 orleave well enough alone ?

[swathdiver]

This is great info thanks. P.O. Put new cats and o2's in mine but not sure what brand he used. He is a BMW tech so hopefully he used decent stuff. Im gonna put a half tak in tomorrow and see what happens.

"EDIT" Just talked to previous owner. He thinks he used Denso or something other than OE

You'll probably not notice any difference with a 1/2 tank, but it will begin cleaning out the chambers and piston tops.

I forget which company is the OE supplier, Denso or Delphi? The Denso looks closest to GM but they are still different.

GM 213-3866:


Denso 2344668:


Delphi ES20013:

 

[belair62]

Without a true ethanol sensor how the heck does it "virtually" sense the ethanol content ?

 

[Onlyone]

Hell I’m going to try it out on the old Denali. Completely forgot about it. Ours is 2.99 vs 4.29 for 91. I’ll bet it will help clean it a bit and give the ol 6.2 some more punch.

 

[petethepug]

Wakey, wakey for the Denali motor .

There is so little info published on how GM uses the up & downstream o2 sensors to calculate the e85 burn in the BCM. Some have actually added the earlier GM e85 sensor to the BCM on a tap that already exists and reads ethanol content live. Yes, it’s already set up for that.

My daughter just inherited her great grandmothers 01 S10 LT extra cab with the 2.2 I-4 and 23k Orig miles. It’s one of the early e85 vehicles GM made. We’re going to fill it with corn juice this week to see if it wakes up the iron duke motor a little.

 

[swathdiver]

Without a true ethanol sensor how the heck does it "virtually" sense the ethanol content ?

From the shop manual:

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 upd ted following each purge-off
sequence. The
fuel alcohol content percentage value can be read on a scan tool.

 

[Fless]

IIRC there may be a calibration update for the GMT900 Flex Fuel calculation algorithm. Might be worth checking with a Tech 2 or via the online programming, or the dealer.

 

[petethepug]

I like that. What a great way for me to spend the rest of those GM reward point redeemable for free service at the dealer.

A word of caution for those who run e85 on this Gen of trucks. If the BCM has to be reset or reprogrammed to the initial baseline learning curve, it can be not be calculated unless the motor is running petrol.

Once the motor’s happy and had all its parameters set against the petrol parameters, you can add e85, and then it’ll do its thing based off corn fuel. If the motor has e85 in the tank on a fresh flash the motor will buck and kick like a banshee.

My Indi tech shared that time consuming learning experience about our 09 Esky fuel pump R&R. He had to call out to a dealer buddy to get that info. Fortunately he was already into the tank for service so dropping it again to drain the e85 was not that painful.

 

[stimpster]

I have been using only E85 for many months. Just completed my 2nd 3000 mile roadtrip. Year round in Indiana. I feel the power bump and get 12.5mpg combined instead of 14-15 for gas. Besides wasting corn, I love E85, and have had no problems. I have less than 60k on the Engine, but the rest of the vehicle had 212k miles....

 

[petethepug]

First time since 01 when new the S10 had e85. Sheesh, day & night difference on the 100hp
I-4 2.2L lump. The truck has the 4SP slushbox and drones from detonation in regular 87 and piss’d off if you get into it to force the kick down.

With a 80/20 fill up on e85 / 87 @ $2 a gal cheaper the drone & detonation are gone. My daughter & I took it up an 8% grade and it actually accelerated, very slowly though. The idle settled down and I have to say, I’m kinda impressed and my daughter’s stoked too.

She shaved $37 off her $90 18 gal fill ups and free’d up some performance to make getting on the highways safer. I’m surprised the e85 sensor woke up after 23 years and performed flawlessly. We now have two corn fuel vehicles.

My daughter just inherited her great grandmothers 01 S10 LT extra cab with the 2.2 I-4 and 23k Orig miles. It’s one of the early e85 vehicles GM made. We’re going to fill it with corn juice this week to see if it wakes up the iron duke motor a little.

 

[tomcoppola]

+1 for E85
I run it almost exclusively in my '07 Tahoe and 01 Corvette (converted w/ AFDs kit). I see, on average, a 22% decrease in fuel mileage w/ E85 which means I only fill up if there is a >22% difference between E10 and E85. Right now on Long Island, NY E85 is 49% cheaper ($2.09/gal), so we're saving money!

In the winter when the vette doesn't get driven, I try to keep E10 in it. I'm sure I could use an additive to prevent hygroscopy, but I haven't tried it.