docs: update configuration/Flex_Fuel

configuration/Flex_Fuel.md

@@ -2,19 +2,19 @@
 title: Flex Fuel
 description: Setting up the flex fuel / ethanol content sensor
 published: true
-date: 2020-01-16T11:37:06.161Z
+date: 2020-01-16T12:09:30.179Z
 tags: 
 ---
 
-Overview
---------
+# Flex Fuel
+
+## Overview
 
 Speeduino has the ability to modify fuel and ignition settings based on the ethanol content of the fuel being used, a practice typically known as flex fuelling. A flex fuel sensor is installed in the feed or return fuel lines and a signal wire is used as an input on the Speeduino board.
 
 As ethanol is less energy dense, but also has a higher equivalent octane rating, adjustments to the fuel load and ignition timing are required.
 
-Hardware
---------
+## Hardware
 
 Speeduino uses any of the standard GM/Continental Flex fuel sensors that are widely available and were used across a wide range of vehicles. These were available in 3 different units, all of which are functionally identical, with the main difference being only the physical size and connector. The part numbers for these are:
 
@@ -38,8 +38,7 @@ All units are wired identically and have markings on the housing indicating what
 
 On boards earlier to these, you will need to add a pullup resistor of between 2k and 3.5k Ohm. Recommended value is 3.3k, however any resistor in this range will work. Note that this is a relatively strict range, more generic values such as 1k or 10k DO NOT WORK with these sensors.
 
-Tuning
-------
+## Tuning
 ![flex_settings.png](/img/flex/flex_settings.png){.align-center width=450}
 
 -   **Sensor frequency -** The minimum and maximum frequency of the sensor that represent 0% and 100% ethanol respectively. For standard GM/Continental flex sensors, these values are 50 and 150