B3601?

[BlackSS]

I'm trying to get my truck tuned for 10% ethanol, I've read in multiple post where it ways to change B3601 to 14.12. My B3601 in a chart (photo attached) not just a single cell like I've noticed on the tunes people have posted. Do I need to change all those to 14.12? I'm assuming this is for a flex fuel vehicle, my tune file has the flex fueloption, which is off, but my truck is not a flex fuel. Thanks for the help.

[joecar]

Yes, correct, the single-celled B3601 is for single-fuel vehicles.

Your ECM already takes care of alcohol composition, so leave your multi-celled B3601 as is.

[BlackSS]

Joe,

Since the truck is not a flex fuel will the table still work? I only ask cause I've never noticed my commanded AFR change from 14.68 at cruising speeds even though I know there is ethanol in my fuel.

[nevinsb]

You can try to change the default ethanol percentage if you don't want to make the table flat.

[BlackSS]

I'm just looking for the correct way to get my tune right. I changed all the cells to 14.12 before I had gotten any replies on this thread. It now commands 14.12, but if that's not the correct way to do it then I'll change everything back to the way it was.

[Chalky]

I can't see how changing any cell other than 0% will make any difference in a non flex fuel vehicle. In all likelyhood, a flex fuel vehicle will have the same tables as your non flex vehicle but with flex fuel option activated. That is when the other cells would be used depending on ethanol content.

I changed a couple of different cars to 14.35 in the 0% cell only to recognize 5% ethanol that we have in our area. It works fine. Of course, both cars were dialed in as far as VE and MAF goes prior to changing to 14.35. :)

[BlackSS]

Is changing the B3601 to match the ethanol content helping with fuel mileage any? I know the change is making it richer so I would think not. My truck has dropped about 1.5mpg since the 10% ethanol hit the pumps.

[Chalky]

Changing B3601 will cause you to consume more fuel. You might be better off leaving B3601 @ 14.63 and just set PE around 12.3. Confirm with a wide band.
12.3:1 AFr is about ideal for 5% ethanol for max safe power. 10% ethanol would require a 12.1:1 AFR PE.

I bought a test kit to confirm ethanol content in my area. I am seeing 5% ethanol in the summer. Not sure what it will look like in the winter.

B3601 seems capable of handling E10 fuel even using factory B3601 settings of 14.63. Only problem is as more ethanol is added to fuel, cruise conditions dictated by 14.63 will cause a leaner mixture. At some point as more ethanol is added to our fuel B3601 will most likely have to be enriched.

[joecar]

If your vehicle has that multi-celled B3601 table, how does it determine the ethanol content % so it can lookup B3601...?

[BlackSS]

Joe,
I don't think the truck has anything to look it up because it is not flex fuel. That is why I was asking questions about the chart so I would make the right changes. Under the flex fuel tab in my tune it shows flex fuel in disabled and that there is not a sensor.

[Chalky]

If your vehicle has that multi-celled B3601 table, how does it determine the ethanol content % so it can lookup B3601...?

From what I understand, the flex fuel vehicles have a sensor in the tank that measures ethanol content. Based on Ethanol content, it will select the appropriate cell in the table in B3601 as stoich for the blend in the fuel tank. With every fuel up, the blend is evaluated again for ethanol content.

[andrewjamesbond1]

Changing B3601 will cause you to consume more fuel. You might be better off leaving B3601 @ 14.63 and just set PE around 12.3.
B3601 seems capable of handling E10 fuel even using factory B3601 settings of 14.63. Only problem is as more ethanol is added to fuel, cruise conditions dictated by 14.63 will cause a leaner mixture. At some point as more ethanol is added to our fuel B3601 will most likely have to be enriched.

The ECM will compensate for the added ethanol by using the fuel trims. Therefore, E10 and pure 87 gas will run stoich in our motors, no matter what mixture between 87 and E10 the pumps have. By changing the desired AFR for E10 and you run E10 all the time, you will see your fuel trims fall back into place, instead of adding fuel. The best would be to split the distance between 87 and E10 for your desired AFR so you can fill up and your trims will be very close no matter which fuel mixture you put in your tank. Now if you put E85 in, thats a different story :D

[nevinsb]

I was figuring you could enable it and set b3103. The sensor isn't actually in the tank, it goes on the fuel line. I got one for mine, but it was bad, so never set it up.

[BlackSS]

Where does the sensor go on the fuel line? Would the factory harness already have a plug for it? Just curious, if it was plug and play it seems like the best way to go. Also I've attached a pic of the flex fuel tab in my tune file to help explain what I'm looking at.11950

[nevinsb]

It isn't plug and play since they were on the 2.2L s10, there is no wires run to the PCM. I have -8 fuel line run to my engine, but it looks like they use the GM quick disconnect fittings. The sensors are stupid expensive, which is why I didn't get another one.

They looked like this:
http://cgi.ebay.com/ebaymotors/Flex-Fuel-Sensor-GM-Trucks-12570260-12568450-NEW-/150517742482?pt=Motors_Car_Truck_Parts_Accessories&hash=item230b8e7b92

There's a used one here too:
http://cgi.ebay.com/ebaymotors/GMC-Flex-Fuel-Sensor-GOOD-CONDITON-Part-GM-12570260-/110743608085?pt=Motors_Car_Truck_Parts_Accessories&hash=item19c8d55b15

[BlackSS]

Thanks for the info, that's out of my price range at the moment.