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Author Topic: True automatic map changing flex-fuel setup for ME7  (Read 32457 times)
nyet
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« Reply #15 on: December 19, 2012, 12:45:08 PM »

A simple FET based buffer circuit could fix this easily, btw.
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« Reply #16 on: December 19, 2012, 12:48:08 PM »

Sorry to burst your bubble, but...

Those sensors are very expensive and unreliable.
This is why the OEM's have dumped them and are using feedback from O2's and knock sensors to create a software Ethanol sensor.
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jibberjive
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« Reply #17 on: December 19, 2012, 12:56:33 PM »

Sorry to burst your bubble, but...

Those sensors are very expensive and unreliable.
This is why the OEM's have dumped them and are using feedback from O2's and knock sensors to create a software Ethanol sensor.
I had heard that the OEM ones were having reliability issues, but they actually quit using them in the US cars?  Because of the questionable reliability, this is the sensor I was planning on trying out, once it has had enough time to get some reviews on it:

http://www.haltech.com/flex-fuel-sensor/
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jibberjive
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« Reply #18 on: December 19, 2012, 12:57:42 PM »

A simple FET based buffer circuit could fix this easily, btw.
Fix what?
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DonSupreme
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« Reply #19 on: December 19, 2012, 01:04:32 PM »

I had heard that the OEM ones were having reliability issues, but they actually quit using them in the US cars?  Because of the questionable reliability, this is the sensor I was planning on trying out, once it has had enough time to get some reviews on it:

http://www.haltech.com/flex-fuel-sensor/

Is that sensor available for purchase? There is no price on that page.

Edit: I found the price. Its $249
« Last Edit: December 19, 2012, 01:36:01 PM by DonSupreme » Logged
nyet
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« Reply #20 on: December 19, 2012, 02:15:19 PM »

Fix what?

.. if there is a voltage mismatch or pullup/pulldown issue
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ME7.1 tuning guide (READ FIRST)
ECUx Plot
ME7Sum checksum checker/corrrector for ME7.x

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience.
britishturbo
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« Reply #21 on: December 19, 2012, 06:51:06 PM »

The newest GM sensor is only $65 btw...
And as far as I know GM went back to using this newer cheaper, more reliable sensor...
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jibberjive
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« Reply #22 on: December 24, 2012, 02:22:22 AM »

The newest GM sensor is only $65 btw...
And as far as I know GM went back to using this newer cheaper, more reliable sensor...
It took some digging to find info on the new GM sensor.  You guys are right, after the failure of the early sensors, GM and Ford went with the "virtual ethanol sensors" that estimated ethanol content via the O2 sensors and fuel level. Now, to comply with the new tier III emission requirements, GM has recently implemented a gen II dielectric flex fuel sensor that actually measures ethanol content again, instead of estimating it.   The gen II sensor is made by the same company who made the first sensors, VDO/Continental.  When digging for info, I made the curious discovery that these look strikingly similar to the Haltech sensor:

http://www.usa.vdo.com/generator/www/us/en/vdo/main/press/releases/aftermarket_replacement_parts/2012/sv_CO1483_C.html





Like Britishturbo said, these Continental sensors can be had for ~$65, but he didn't mention it's the exact same as the Haltech ($226!).  Pleasant surprise!

The part #'s are 13577394 and 13577379, the difference between the two being the length of fuel connections (the 13577394 being longer).  They can be bought from www.gmpartsdirect.com for ~$66.



Here's some info about the new flex fuel sensor

Quote from:  l
Flex Fuel Sensor

The flex fuel sensor measures the ethanol-gasoline ratio of the fuel being used in a flexible fuel vehicle. Flexible fuel vehicles can be operated with a blend of ethanol and gasoline, up to 85 percent ethanol. In order to adjust the ignition timing and the fuel quantity to be injected, the engine management system requires information about the percentage of ethanol in the fuel.

The flex fuel sensor uses quick-connect style fuel connections, an incoming fuel connection, and an outgoing fuel connection. All fuel passes through the flex fuel sensor before continuing on to the fuel rail. The flex fuel sensor measures two different fuel related parameters, and sends an electrical signal to the engine control module (ECM) to indicate ethanol percentage, and fuel temperature.

The flex fuel sensor has a three-wire electrical harness connector. The three wires provide a ground circuit, a power source, and a signal output to the ECM. The power source is battery positive voltage and the ground circuit connects to an engine ground. The signal circuit carries both the ethanol percentage and fuel temperature within the same signal, on the same wire.

The flex fuel sensor uses a microprocessor inside the sensor to measure the ethanol percentage and fuel temperature, and changes the output signal accordingly. The electrical characteristic of the flex fuel sensor signal is a square-wave digital signal. The signal is both variable frequency and variable pulse width. The frequency of the signal indicates the ethanol percentage, and the pulse width indicates the fuel temperature. The ECM provides an internal pull-up to 5 V on the signal circuit, and the flex fuel sensor pulls the 5 V to ground in pulses. The output frequency is linear to the percentage of ethanol content in the fuel. The normal range of operating frequency is between 50 and 150 Hz, with 50 Hz representing 0 percent ethanol, and 150 Hz representing 100 percent ethanol. The normal pulse width range of the digital pulses is between 1 and 5 ms, with 1 ms representing −40°C (−40°F), and 5 ms representing 151.25°C (304.25°F).

The microprocessor inside the sensor is capable of a certain amount of self-diagnosis. An output frequency of 180 Hz indicates either that the fuel is contaminated, or that an internal sensor electrical fault has been detected. Certain substances dissolved in the fuel can cause the fuel to be contaminated, raising the output frequency higher than the actual ethanol percentage should indicate. Examples of these substances include water, sodium chloride (salt), and methanol.

It should be noted that it is likely that the flex fuel sensor will indicate a slightly lower ethanol percentage than what is advertised at the fueling station. This is not a fault of the sensor. The reason has to do with government requirements for alcohol-based motor fuels. Government regulations require that alcohol intended for use as motor fuel be denatured. This means that 100 percent pure ethanol is first denatured with approximately 4½ percent gasoline, before being mixed with anything else. When an ethanol gasoline mixture is advertised as E85, the 85 percent ethanol was denatured before being blended with gasoline, meaning an advertised E85 fuel contains only about 81 percent ethanol. The flex fuel sensor measures the actual percentage of ethanol in the fuel.

So the "ECM provides an internal pull-up to 5 V on the signal circuit, and the flex fuel sensor pulls the 5 V to ground in pulses".  Does anyone know if that is how the stock EGT's work, with the ECM providing the pull-up voltage?  If so, it looks like it's going to be perfect to use the EGT's 3 wires to power and send the signal from the flex fuel sensor.

I'm banking on these new sensors being more reliable than the old ones, and if they prove to suck, at least they're a lot cheaper. I'm excited to try this out!
« Last Edit: December 24, 2012, 03:57:50 AM by jibberjive » Logged
terok
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« Reply #23 on: December 25, 2012, 12:21:31 PM »

VAG (propably among others) is using this same Continental sensor in their flexfuel cars, so it can't be that bad Smiley
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prj
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« Reply #24 on: December 25, 2012, 03:41:54 PM »

Seems my info was a little out of date.
I looked into flex fuel a long time ago the last time, and when I looked into it, that was the case.

If they have come up with a cheaper and more reliable sensor, then that is good.

One thing I am worried about slightly - how big is the orifice on the sensor? Is it any good for high power setups? It says that all fuel has to pass through it.
Or am I misreading it?
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britishturbo
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« Reply #25 on: December 25, 2012, 03:48:37 PM »

Seems my info was a little out of date.
I looked into flex fuel a long time ago the last time, and when I looked into it, that was the case.

If they have come up with a cheaper and more reliable sensor, then that is good.

One thing I am worried about slightly - how big is the orifice on the sensor? Is it any good for high power setups? It says that all fuel has to pass through it.
Or am I misreading it?

Just put a T in the return line and run some of the fuel through it. You're Ethanol % will not change much at all from minute to minute...
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MIL_on
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« Reply #26 on: March 24, 2014, 11:56:17 AM »

Hi Guys,
With E85 becoming more and more popular in the Scene even more people see themselves confronted with the problem of lacking e85 gas stations. So the only possibility to do a "flex fuel" is the known method by bringing the FTs to their limits with either one of the fuels and hope that LR will make it fit or be a strict either/or fueller. But wouldnt it be cool if we could fit in a real flex fuel routine?
The sensor for this is easy to get...it even has a VW Partnumber and is fabricated by Continental: 06K907811. I would say the price being ~150€ is also acceptable. Its even easy to install...
Wouldnt it be possible to use the 2nd O2s as an input for the sensor and manipulate fueling and Ignition based on that Voltage?
« Last Edit: March 24, 2014, 12:02:32 PM by MIL_on » Logged
ddillenger
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« Reply #27 on: March 24, 2014, 12:09:41 PM »

Your topic is the exact same as a current discussion. As such, I merged it.
« Last Edit: March 24, 2014, 12:11:21 PM by ddillenger » Logged

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MIL_on
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« Reply #28 on: March 24, 2014, 02:48:49 PM »

Oopsie, sorry and thanks! Didnt see this topic in the last days
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overspeed
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« Reply #29 on: March 24, 2014, 03:34:38 PM »

here in Brazil, there is no dedicated sensor to measure Ethanol proportion...

All is calculated by logic + O² readings + knock activity (it´s called SFS by Marelli - software Flexfuel System)

I posted some time ago files used by Golf 1.6 EA113 engine Flex (C20 till E100) to someon who want to disassemble and study, but lost the topic (lol)

There is some tricky issues with this metod, but works Ok for factory...
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