Ethanol percentage flex fuel

[iamdub]

Ya know sumpin... I was having odd alcohol content readings last I tried the stuff. Filled up from RaceTrac and my fuel rail sample showed something like 65%. My Tahoe always reported in the 20s and seemed to hover on 22%. I quit running it because there's no point- If the PCM doesn't see the higher content, it's not gonna adjust accordingly. This will result in less power along with the weaker fuel, surely negating any cost-per-mile savings.

More recently, I had to replace my EVAP canister and purge valve and blow carbon pellets out of all the lines due to the old canister puking them out. Now I'm wondering if they were causing issues back then, screwing up the EVAP purge process and causing the alcohol content to be measured inaccurately.

 

[wsteele]

Ya know sumpin... I was having odd alcohol content readings last I tried the stuff. Filled up from RaceTrac and my fuel rail sample showed something like 65%. My Tahoe always reported in the 20s and seemed to hover on 22%. I quit running it because there's no point- If the PCM doesn't see the higher content, it's not gonna adjust accordingly. This will result in less power along with the weaker fuel, surely negating any cost-per-mile savings.

More recently, I had to replace my EVAP canister and purge valve and blow carbon pellets out of all the lines due to the old canister puking them out. Now I'm wondering if they were causing issues back then, screwing up the EVAP purge process and causing the alcohol content to be measured inaccurately.

Hope so, it sure will simplify my life if it does....

PS - I haven't had any fill issues, but I have to admit to being one of those "top it up real good" kind of people, at least until I learned about canisters and pellets floating around...

 

[George B]

I get it, was just explaining the set up I have. If I were going to fill that little beaker up a the gas station, I would surely spill more on the ground that goes into the little bottle. It'll evaporate quick enough though but sure would stink up my hands unless wearing gloves. I got it, pump some into a bowl and then submerge the beaker in that to get a sample. Yeah, that'll work.

I bought this one off ebay, the numbers are etched into the glass, no sticker.

On another thread a member posted about having an empty small gas can in the truck. Pump some in the truck then into the can then into the truck. Test out of the can and dump the rest into the truck s few days later. Then let the can drynput for the next time.

 

[wsteele]

On another thread a member posted about having an empty small gas can in the truck. Pump some in the truck then into the can then into the truck. Test out of the can and dump the rest into the truck s few days later. Then let the can drynput for the next time.

Probably was me. That is my plan in any case. I have a number of 1 gal cans I used for power landscape tools like trimmer, chain saw, snow blower, etc.

 

[swathdiver]

On another thread a member posted about having an empty small gas can in the truck. Pump some in the truck then into the can then into the truck. Test out of the can and dump the rest into the truck s few days later. Then let the can drynput for the next time.

Even my old cans without the government nozzles, I think I'd spill gasoline on my hands trying to fill that little thing up. Might work if I was real careful like.

 

[wsteele]

Gasspouts.com, when you really don’t want to spill gas out of your CARB compliant gas can.

Not cheap, but worth every penny.

Not available in CA, shame really.

 

[YukonDoit2003]

So I am fulling up my tank with E85 lately, should I be recalibrated the PCM to run on E85? I save a ton at the pump, although I am losing some MPG. Can you recommend a good scan tool app?

 

[jmm121783]

Little background....

I EXCLUSIVELY run E85 in my 850hp+ CTSV, except when stored for winter. With my Aeroforce Gauge I am constantly checking my Alcohol % levels after fill up in order to find the best E85 in my area. There are a LOT of stations that "water-down" E85 (which by definition should be 85% alcohol) or just have subpar quality E85. In Michigan, technically, E85 only has to contain 50% ethanol. I prefer Speedway E85 to just about any other brand as it is the most consistent, is high quality, clean and typically comes in at 78% alcohol. I run E85 in my Tahoe whenever it makes sense (the price should be 25% cheaper to make it worthwhile since you loose about 15-20% MPG.

1) Ethanol is in all gas, up to 10% in most states
2) If you sensor is not settling on a number after driving around a few miles your sensor might be bad or you could have some sort of clog or buildup?
3) E % changes throughout the year (and from different vendors) on normal gas and e85, especially in the winter which is why typically see a loss of mileage during winter months
4) I have never experienced any sort of rough running or a "struggling" motor due to E % varying
5) E85 should smell SWEET when coming out of the tailpipe, nothing like the smell of normal gas
6) Other than a custom tune, you should NEVER have to re-calibrate your FF Sensor unless there was an ECM swap or you are troubleshooting a possible faulty sensor
7) All gas stations are not created equally, if you haven't figured that out already or by reading my pointers above

 

[wsteele]

So I am fulling up my tank with E85 lately, should I be recalibrated the PCM to run on E85? I save a ton at the pump, although I am losing some MPG. Can you recommend a good scan tool app?

I wouldn’t expect any need to recalibrate anything to run a flex fuel vehicle on E85.

To just monitor things, read engine codes, etc. I bought a cheapie ELM427 ODBII dongle that plugs into my ODB port and uses my iPhone with a free app that also uses ELM 427. There are many for sale on Amazon. Just heed the reviews and make sure it clearly states it works with IOS or Android depending on what phone you have. I bought the Viecar Bluetooth one and it works well with the Car Scanner iPhone app.

Good luck.

 

[Fless]

Little background....

I EXCLUSIVELY run E85 in my 850hp+ CTSV, except when stored for winter. With my Aeroforce Gauge I am constantly checking my Alcohol % levels after fill up in order to find the best E85 in my area. There are a LOT of stations that "water-down" E85 (which by definition should be 85% alcohol) or just have subpar quality E85. In Michigan, technically, E85 only has to contain 50% ethanol. I prefer Speedway E85 to just about any other brand as it is the most consistent, is high quality, clean and typically comes in at 78% alcohol. I run E85 in my Tahoe whenever it makes sense (the price should be 25% cheaper to make it worthwhile since you loose about 15-20% MPG.

1) Ethanol is in all gas, up to 10% in most states
2) If you sensor is not settling on a number after driving around a few miles your sensor might be bad or you could have some sort of clog or buildup?
3) E % changes throughout the year (and from different vendors) on normal gas and e85, especially in the winter which is why typically see a loss of mileage during winter months
4) I have never experienced any sort of rough running or a "struggling" motor due to E % varying
5) E85 should smell SWEET when coming out of the tailpipe, nothing like the smell of normal gas
6) Other than a custom tune, you should NEVER have to re-calibrate your FF Sensor unless there was an ECM swap or you are troubleshooting a possible faulty sensor
7) All gas stations are not created equally, if you haven't figured that out already or by reading my pointers above

A little clarification:

1) Some stations do carry ethanol-free gas, so not ALL gas contains ethanol. I use this in my small engines and in my DD.

3) The ethanol percentage is generally lowered in colder seasons due to high ethanol content causing hard starting.