FLEX FUEL SENSORS HOWS AND WHYS
 

I have been getting a lot of questions regarding adding a flex fuel sensor for use with E-85.

There seems to be a lot of misinformation regarding this so I am starting this thread to hopefully educate and put to rest some of the misinformation.

Some how people are getting the impression you can purchase and install a sensor and your good to go, NOT the case at all.

Q. Can I add a flex fuel sensor to my car?

A. Yes, you can but it will do nothing without custom tuning to activate it.

Q. OK after the flex fuel sensor can I burn E-85?

A. NO, you do not have large enough injectors or fuel pump to supply the 30% more fuel volume needed.

Q. What is required to burn E-85 in my ZL-1?

A. That will depend on RWHP target, Example, for 500 RWHP you could get away with ID-850s, a JMS fuel pump voltage booster, a Flex fuel sensor, and custom tuning.

A2. For most modified ZL-1 it will require a complete Squash or Fore, twin pump, return system, with PTFE lines and fittings, ID-1300 injectors, and a one of our Flex Fuel sensor kits at a cost of around 4200.00 in parts and 10 hours of labor and of coarse custom tuning to make it all work.

Q. How much more power an I expect from E-85?

A. This is a loaded question, again it will depend on how extensive your mods are now and how badly you need more octane.

A2. Example 1, 770 RWHP 93 oct combo makes 850 RWHP on E-74, total 80 RWHP gain

A3. Example 2, 630 RWHP 93 oct combo makes 685 RWHP on E-68, total 55 RWHP gain

Q. What is E-85, E74, E68?

A. It is the percentage of Ethanol vs Gasoline in the mixture, when you buy E-85 you don't always get E-85 you often get E-74.

Q. How do you know this?

A. The Flex fuel sensor reports this to the computer and can be logged or read through the OBDii port.

Q. With a complete flex fuel conversion can I switch between 93 and E-85

A. Yes you can when set up correctly the computer will compensate for the Stoich value and timing requirements.

Q. What needs to be done to the tune to enable Flex fuel capability?

A. A full custom tune must be made on the dyno first on 93 then enable the flex fuel sensor, the flex fuel timing and fueling tables must be set up as they are currently all Zeros.

I will be happy to add to this thread with anyone's additional questions, these are the most common I have been getting.

Ted.

Thanks Ted, this is very useful information!

BTW, would you happen to know the PID for the sensor reading for those of us who would rather use an app or Dashlogic instead of a dedicated gauge?

Alcohol Percent

I have a question for you.
I bought one of your FFS and fuel systems late last year, got everything installed but have hit a wall with the FFS wiring. The sensor has 3 wires (ground) pretty easy, (12V switched) not to sure and (Voltage out which is supposed to go to pin 40 on the ECM) seriously not sure on this one.

I can hold my own with the mechanical stuff but when it comes to wiring I struggle so any help with this would be great for me and anyone considering this mod.

Anyone know where the #40 pin is?

If you look carefully the connectors are numbered at each corner/ end of row

And that would be gray, black or blue?

I just checked with my installer, Blue pin number 5 on the ZL-1.

I'm trying to do the same thing and I can't see any dang numbers. Any pics would help Ted.

The numbers are located on the ECM right in the corners not on the connectors.

Here is the diagram from a 2010-2011 service manual. I added the arrows and circle to show the location of pin 40.

Excellent thanks guys.

PIN #5? PIN#40?http://www.chevythunder.com/Gen%20IV%20E67%20ecm.jpg

Ted says for the ZL1 it's blue pin 5 which would be 5th from the bottom left. See the number 1? I would say count 5 up from there. I'm going to call him just to make sure. Pin 40 is for the SS I think.

As an aside, the only station that carries E-85 within 60 miles was out of service today. Luckily I went with enough gas in the tank still so I could go all the way home, about 20 miles. Will call first next time!! I need this flex fuel sensor installed soon!!

In the ZL1 ECM it looks as if the majority of the tables to switch over to using flex-fuel with a sensor are already there populated with what appears to be data t hat is either correct or reasonably close.

For those with HPT, after installation of the sensor what else must be done?