swathdiver
Full Access Member
I suspect that a vacuum or exhaust leak can trigger a relearn because the fuel trims are upset by such.
Ethanol percentage flex fuel
- Thread starter wsteele
- Start date
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So far, the only condition that seems to trigger the relearn on my truck is filling the tank. After a fill-up, when I drive enough (like 10+ miles) it will settle on a number it likes. Then the next cold start seems to cause it to make a final decision and the number usually jumps quite a but from the last calc. It will then stay at that spot until the next fill.
Today, I had a second start and drive today, after the fill. It was a warm start, so I wonder of it even got to open loop. After I started the engine, it was displaying 19.38% (down a few percentage points from when I turned it off the first trip after the fill).
It will be interesting if it stays there or goes lower/higher when I do the cold start tomorrow.
OK, final update for this fill. The E% calc after the first cold start after a fill (I had two warm starts after the fill), the % is the same as the final calc after the second warm start, 19.38%. About 19% above what is actually in the tank. 
I changed the canister purge valve to a new OEM unit and also installed a new OE E85 gas cap and did get a monitor complete on the Evap, so it looks like the canister purge valve isn’t playing a role in the poor performance of the virtual ethanol sensor.
I am thinking I am not going to get to the bottom of this issue. Glad I got the Tech 2 to reset it to 3% when it gets up into the 30’s percentage range.
I changed the canister purge valve to a new OEM unit and also installed a new OE E85 gas cap and did get a monitor complete on the Evap, so it looks like the canister purge valve isn’t playing a role in the poor performance of the virtual ethanol sensor.
I am thinking I am not going to get to the bottom of this issue. Glad I got the Tech 2 to reset it to 3% when it gets up into the 30’s percentage range.
Is the calculated ethanol percentage something one can monitor using a Bluetooth dongle and one of the Android apps? If so, which apps, and would it require buying the enhanced PIDs version (vs. the free version)?
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Yes, I am using a simple ELM327 Bluetooth dongle (like $20) and a free app called Car Scanner. The dongle is sold by Viecar, but I think there are myriad other vendors selling the same thing. I chose Bluetooth because the iPhone seems to have problems with some WiFi versions. I think Android works with both pretty well.
I did do the lifetime upgrade to the Pro version of the app, for like $6, because it allows me to display more simultaneous parameters, but the free version works fine as well, just limited to like 2 variables at the same time.
Edit, here is what I bought. It went up $5 since I bought mine (like everything else in the world).
https://www.amazon.com/Viecar-Bluetooth-Android-Diagnostic-Multi-Brands/dp/B01MTKSCEJ/ref=sr_1_5?crid=1TZZGXZQ5DZDM&dchild=1&keywords=viecar+bluetooth+4.0+elm327&qid=1621533523&sprefix=Viecar,aps,222&sr=8-5
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swathdiver
Full Access Member
Haven't been able to pull up Alcohol Content with the Torque Pro app but can see it with the Dash Command app.
Mine is staying at 73% today. Almost time to refuel, next time out probably.
I assume you are using E85. Have you used the water bottle test to see how your virtual sensor is doing versus the actual content of your E85?
Thanks. I have the OBDLink MX+ Bluetooth dongle, just need to figure out a good Android app for the small tablet I use.
swathdiver
Full Access Member
I have in the past but not lately. I'll see about pulling another sample soon.
Holy smokes, so your truck thinks it has 73% Ethanol and you are pumping E10?
