Technical Support

Installation instructions

From this page you'll find everything needed in the installation of an eFlexFuel device. Installation instructions (PDF)

Also check the quick guide for eflexfuel.


Table of contents


1. Before you begin

Go through the following checklist before installing the device. Do not refuel with ethanol before the installation.

Check that the product package contains the right components

Check that the accessories kit contains the right components

Tools needed:

  • Multimeter
  • In addition, you may need a fuel line opening tools, screw drivers, or similar basic tools.

Check the following before moving on to the next phase


2. Preparation

Check the video below to see what needs to be done before the installation.


3. Installation

3.1 Disconnecting the fuel line

Ethanol sensor can be connected to either the fuel return line or the pressure line. Fuel flow direction doesn't affect the reading of the sensor. Ethanol sensor should be installed near the fuel rail.

  1. Open the fuel filling cap to release the pressure.
  2. Ethanol sensor should be installed to a location free from moving parts and high temperatures. Engine movement may cause rubbing to the fuel hose if installed incorrectly. Installing to a hot environment may cause melting of the fuel hose which can lead to slipping or leaking of the fuel hose. Clean the fuel line connection before disconnecting them.
  3. Clean the connectors before disconnecting.
  4. The fuel hose should be installed as straight as possible. Avoid tight bends. Minimum radius for a bend is 80 mm (3.1 in). Tight bending of a fuel hose may cause breaching and leaking
  5. Use quick connectors in installing the ethanol sensor.
  6. If a fuel hose is added during the installation, use the fuel hose included in eFlexFuel accessories kit.
  7. Do not use solvents when installing the fuel hose.
  8. Lubricate the quick connector seals with clean engine oil before installation.

3.2 Installation of the ethanol sensor

Installation, figure F:

  1. Ethanol sensor
  2. Ethanol sensor connector (figure A; 4)
  3. Fuel hose and hose clamps
  4. Fuel line quick connector

After installing the quick connectors, make sure they are properly locked by pulling the connector back and forth.

Check the video below to see the correct way to attachthe fuel line:

Check the following before moving to the next phase

3.3 Wiring harness

Wiring harness, figure A:

  1. Strip connector
  2. Ground wire
  3. Temperature sensor
  4. Ethanol sensor connector
  5. Fuel injector connector (female)
  6. Terminal couple for male connectors
  7. Male connector
  8. Expansion connectors (5-8 cylinder vehicles)
  9. Expansion wiring harness (5-8 cylinder vehicles)

Disconnect the fuel injectors connectors, figure B:

  1. The fuel return line
  2. Fuel rail
  3. The fuel supply line (pressure line)
  4. Fuel injector
  5. The original fuel injector connectors

Remove the connectors connected to the fuel injectors.

Before proceeding with the installation make sure your vehicle's fuel connectors are compatible with the contents of the product package. If the connectors do not fit, please contact the seller.

3.4. The polarity of the injector connector

Check the polarity of the injector connectors so the wiring harness can be connected correctly. Use multimeters conductivity position (beep-position). Normally positive side (+12 V) has the same wiring color.

Measure all the connectors the same way. Remember which terminal made the beep sound. You will need this information later on.

3.5. The polarity and installation of the male connectors

Check which way the male connector plugs in. Push the red wire of the wiring harness to the male connector. Make sure that the red wire inserts to the same side the tone indicated.

3.6. The installation of the wiring harness

Once the male connectors are connected to the wiring harness, it is ready to be installed to the vehicle. Do not change the order of the original connectors! eFlexFuel injector wires can be in any order. The connector pair with the double red wires (can also be marked with a red shrink tube) (+12V) needs to be always connected so that eFlexFuel gets its operating voltage and main functions.

  1. Connect the male connectors of the eFlexFuel wiring harness to the vehicle's injector wires you disconnected earlier
  2. Connect the female connectors of the eFlexFuel wiring harness to the injectors

Note when installing eFlexFuel to motorcycles

If the engine is equipped with two injectors per one cylinder (for example 4 cylinders and 8 injectors), the first cylinder wire from eFlexFuel must be connected to the primary injectors. Primary injectors are the ones closer to the cylinder head. If the first cylinder wire is being installed to secondary injectors, eFlexFuel do not work properly.

Install the temperature sensor

A good place for temperature sensor is near the cylinder head next to the fuel injectors or under the ignition coil cover. The temperature sensor must not be installed near the engine exhaust manifold.

Installing the control unit

Find a proper location in the engine bay. Make sure that the control unit is not exposed to excessive heat or moisture. Also make sure that the control unit is not touching moving parts.

Secure the wiring harness

Make sure that the terminals of the control unit's main connector are straight before connecting the wiring harness. Connect the wiring harness to the control unit. You only need just a little bit of force. Make sure that the connector is securely attached

Connect the wiring harness to the ethanol sensor.

3.7. Connect the ground wire

Connect the ground wire either directly to the negative terminal of the vehicle's battery or to the metallic chassis of the vehicle. Make sure that the ground wire is connected properly.

Check the following before moving to the next phase

3.8. Finalizing the installation

Attach the wiring harness to the engine compartment. Make sure the harness has a little bit of slack for engine movement and it does not touch any moving or hot parts. The wiring harness can safely withstand 100 °C (212 °F) temperature but avoid attaching it to the engine´s hottest parts.

  1. Start the engine
  2. The engine should be running normally. However, the first startup after the installation may be a bit longer if the ethanol sensor is installed in the pressure line and fuel line is drained empty
  3. When you have started the engine, observe the installed fuel line connectors and fuel hose. Even a small leak could cause a fire hazard
  4. If vehicle won’t start, check the ground wire connection
  5. If vehicle runs badly, check the polarity of fuel injector connectors and that the connectors are connected properly
  6. You can monitor the control unit with the mobile application
  7. Installation is ready and you can now refuel gasoline, E85 or any mixture of these in your vehicle

The installation is ready and you can now refuel gasoline, E85 or any mixture of those in your vehicle.

Check the following after the first start


4. Cold weather

If you encounter any problems with starting the engine in cold temperatures, avoid long cranking. It is best to do short start-ups keeping a few seconds pauses and wait a few seconds before the next start. This helps ethanol to evaporate in the engine before attempting to start engine again and this way eFlexFuel makes adaptation corrections.

If cold starting gets worse we recommend using an engine block heater or adding 5 - 10 % of regular gasoline to the E85-based fuel mixture.