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Old 12-04-2015, 07:28 AM   #1
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Default Flex fuel sensor reading high

I have finally installed my flex fuel sensor on my 9093 mspnp g2.
In the settings I have 50hz at the min and 150hz as the high. It's is a continental unit (GM)same pn# as the haltech unit.

I have 93 Kentucky gas in it which I assume has at most 10% ethanol, however in tuner studio it is reading 30%!!
If I change around the min frequeny in the tuner studio settings I can get it to read, e10 but then when I added 3~ gallons of e85 to top of the 12~ gallon tank it was showing e50 anyone else have experience with ms and flex fuel sensors.
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Old 12-04-2015, 09:51 AM   #2
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No personal experience, but I'm definitely interested to learn more.

My method would be to fill with E10, set low end reading so it reads 10%. Run the tank empty. Fill with E85, set the low end reading so it reads 85%. Ideally I'm sure you would want to test the gas going in the car, but I feel like that would get you a datapoint at each end of the scale so you could reliably interpolate between the two.
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Old 12-04-2015, 10:02 AM   #3
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Originally Posted by pdexta View Post
No personal experience, but I'm definitely interested to learn more.

My method would be to fill with E10, set low end reading so it reads 10%. Run the tank empty. Fill with E85, set the low end reading so it reads 85%. Ideally I'm sure you would want to test the gas going in the car, but I feel like that would get you a datapoint at each end of the scale so you could reliably interpolate between the two.
Don't do this. E85 is rarely true e85, more often that not it can be as low as e70. You need to get a baseline measurement and figure out what's going on. You may have a defective sensor. Try to find a station around you with ethanol free gas.
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Old 12-04-2015, 11:37 AM   #4
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Originally Posted by pdexta View Post
No personal experience, but I'm definitely interested to learn more.

My method would be to fill with E10, set low end reading so it reads 10%. Run the tank empty. Fill with E85, set the low end reading so it reads 85%. Ideally I'm sure you would want to test the gas going in the car, but I feel like that would get you a datapoint at each end of the scale so you could reliably interpolate between the two.
Unless you're mixing the E10 and E85 blends yourself, you have no earthly idea what the actual compositions are. Do not do this.
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Old 12-04-2015, 11:38 AM   #5
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Unless you're mixing the E10 and E85 blends yourself, you have no earthly idea what the actual compositions are. Do not do this.
x1million
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Old 12-04-2015, 11:59 AM   #6
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There is a possibility that the sensor is dead or perhaps there is a little water in my tank. that can cause havock with these sensors.
Need to empty the tank and run strate e0 93 then attempt again.
Any one had any experience with ms and flex fuel sensors reading high?
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Old 12-04-2015, 12:05 PM   #7
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experience with ms and flex fuel sensors
Not much of this exists. Yank is running one with success. I have one on my shelf.
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Old 12-04-2015, 12:12 PM   #8
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Like I said, no personal experience, and I'm interested to learn more. I'll try to be more careful with my assumptions, certainly not intending to harm anyone's car. I'd love to see more Flex Fuel info on the site and hope this leads toward a constructive conversation.

If you have a safe tune on what comes out of the pump labeled as "E85" and reads 85% ethanol on your sensor, and a safe tune on what comes out of the pump labeled "E10" and reads 10% ethanol on your sensor, then I assumed a linear blending of those two tunes would result in a safe tune. The fact that those ethanol percentages may be off slightly doesn't seem like it would matter. If that's incorrect I'd love to understand why.

If you can't calibrate a sensor based on available information, what is the solution? I know you said find no-ethanol gas, but then what? Are these sensors just supposed to be 100% calibrated and you shouldn't adjust them?
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Old 12-04-2015, 12:12 PM   #9
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Hmm I wounder if there is something similar to calibration tables for Afr sensors and ait sensors. that can adjust the calibration of the flex fuel readings within tuner studio.
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Old 12-04-2015, 12:17 PM   #10
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Originally Posted by pdexta View Post
Like I said, no personal experience, and I'm interested to learn more. I'll try to be more careful with my assumptions, certainly not intending to harm anyone's car. I'd love to see more Flex Fuel info on the site and hope this leads toward a constructive conversation.

If you have a safe tune on what comes out of the pump labeled as "E85" and reads 85% ethanol on your sensor, and a safe tune on what comes out of the pump labeled "E10" and reads 10% ethanol on your sensor, then I assumed a linear blending of those two tunes would result in a safe tune. The fact that those ethanol percentages may be off slightly doesn't seem like it would matter. If that's incorrect I'd love to understand why.

If you can't calibrate a sensor based on available information, what is the solution? I know you said find no-ethanol gas, but then what? Are these sensors just supposed to be 100% calibrated and you shouldn't adjust them?
Because as I said before. A pump labeled E85, DOES NOT MEAN 85% ETHANOL. Some places it can be as low as e70. And this makes a big difference. Sometimes it can be 85%, sometimes 70%.

The sensors read 50hz at 0% ethanol. and 150hz at 100% ethanol. Its different than a variable voltage sensor, for which the ADC sometimes needs to be calibrated. OEMs trust them from the factory, I assume we should too. Which is why I suggested a dead sensor, and that he should test it with e0, because that should give 50hz. If you can scope it that would be even better.

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Originally Posted by willerdcraft View Post
Hmm I wounder if there is something similar to calibration tables for Afr sensors and ait sensors. that can adjust the calibration of the flex fuel readings within tuner studio.
Calibration is 50hz=0% ethanol. 150hz=100% ethanol.
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Old 12-04-2015, 12:17 PM   #11
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Originally Posted by willerdcraft View Post
Hmm I wounder if there is something similar to calibration tables for Afr sensors and ait sensors. that can adjust the calibration of the flex fuel readings within tuner studio.
I assumed there would be since there is with everything else. If not, then that answers my questions.
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Old 12-04-2015, 12:20 PM   #12
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You can calibrate if if you have a well known value. Which is why I suggested getting some e0. Getting e100 might be hard.
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Old 12-04-2015, 12:26 PM   #13
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Old 12-04-2015, 12:31 PM   #14
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Irrelevant. E100 means 100% ethanol 0% gasoline. Not 100% pure ethanol.
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Old 12-04-2015, 12:33 PM   #15
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How can 100% ethanol not be 100% ethanol? 100 percent meaning allofit.
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Old 12-04-2015, 12:40 PM   #16
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Originally Posted by aidandj View Post
Because as I said before. A pump labeled E85, DOES NOT MEAN 85% ETHANOL. Some places it can be as low as e70. And this makes a big difference. Sometimes it can be 85%, sometimes 70%.
I don't know if you just can't comprehend what I wrote or if you just didn't read it, but either way it makes trying to have a conversation totally pointless.
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Old 12-04-2015, 12:43 PM   #17
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How can 100% ethanol not be 100% ethanol? 100 percent meaning allofit.
Do you read your post linked? It talked about distilling ethanol.

E85 does not mean 85% pure ethanol. It means 85% is ethanol that is distilled to be as pure as possible. E100 means no gasoline added to that. You guys are slow as **** this morning.
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Old 12-04-2015, 12:47 PM   #18
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Originally Posted by pdexta View Post
If you have a safe tune on what comes out of the pump labeled as "E85" and reads 85% ethanol on your sensor, and a safe tune on what comes out of the pump labeled "E10" and reads 10% ethanol on your sensor, then I assumed a linear blending of those two tunes would result in a safe tune. The fact that those ethanol percentages may be off slightly doesn't seem like it would matter. If that's incorrect I'd love to understand why.
Because for like the 3rd time what comes out of the pump is not always e85. And varying percentages can mean anything from low on power to destroying your engine.

Let's say you set up your sensor so e75 reads as 85% ethanol, and e10 reads as 10%. Your whole blend is screwed up. What if you then mix in some e83. Now you are over your calibrated "85%" ethanol. Something you might not have tuned for
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Old 12-04-2015, 01:07 PM   #19
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Do you read your post linked? It talked about distilling ethanol.

E85 does not mean 85% pure ethanol. It means 85% is ethanol that is distilled to be as pure as possible. E100 means no gasoline added to that. You guys are slow as **** this morning.
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Irrelevant. E100 means 95% ethanol, 5% water, 0% gasoline. Not 100% pure ethanol.
^So you meant that?^
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Old 12-04-2015, 01:10 PM   #20
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No, quit being ******* pedantic, it probably has all sorts of **** in it. But the designation e85 is the percentage of "ethanol" (percentage of actual pure ethanol i have no idea) compared to the percentage of gasoline. I'm not trying to argue about the contents of ethanol, ****, i don't even care. I'm trying to explain to you what it means in terms of ethanol blended fuel. And I'm about to give up.
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