BRZ/FRS/GT86: 750cc Injector Installation and Calibration

BRZ/FRS/GT86: 750cc Injectors Kit Manual

High Flow Motorsport 750cc Injector Kit

These direct replacement high-low 750cc Motorsport Injectors are suitable for replacing the standard port injectors for power outputs over 300bhp. Included in the package are… 

  • 4x 750cc high flow fuel injectors
  • 4x wiring harness adapters
  • 4x New lower seals
  • Fitting Instructions and Tuning Tips

Once you have installed the high-flow injectors it will be necessary to calibrate the ECU with the correct settings ofInjector Flow Scaling, Injector Lag Time Offset and the cranking fuel tables in EcuTek ProECU software before you start the engine.

The job of installing the new injectors and recalibrating the system should take approximately one hour to complete. 


  1. Disconnect the battery negative terminal

  2. Remove the two injector covers which are retained by two M8 thread (12mm head) bolts on each side.

  3. The direct injector control unit must be separated from one of the covers before attempting to remove it. This is retained by 3x M6 (10mm headed) bolts.

  4. Gently position the control unit to one side then remove the metal cover (2x M8 bolts).

  5. You will now be able to see the port injectors and fuel rails; disconnect the electrical connectors from the injectors, loosen the vehicle fuel-filler cap to release fuel tank pressure, and remove bolts 1 and 2, which are shown below. 

  6. Gently pull the fuel rail away from the inlet manifold, remove the lower rubber seals from the manifold openings (new seals are supplied with the kit) and remove each injector by pulling them clear of the fuel rail. Ensure the upper seals stay on the injectors when they are removed from the fuel rail.

Fitting the new injectors

  1. Remove the two protective silicone caps from each of the EcuTek injectors. Lubricate the upper and lower seals sparingly with petroleum jelly or clean fuel, then carefully push the injectors, firstly into the fuel rail, then into the inlet manifold openings, ensuring the lower seals locate correctly.

  2. Fit the EcuTek injector wiring adaptors between the new injectors and original injector wiring. The remainder of refitting is as per removal instructions, though in reverse order. Be careful not to trap any wiring when refitting the metal covers, ensure all bolts are correctly secured, and re-tighten the vehicle fuel-filler cap.

  3. After physical installation of the new EcuTek fuel injectors you need to modify some settings in the ROM file, using ProECU.  


Injector Scale

These can be found at Maps by Function → Fuelling → Injector Scaling → Port Injector Scaling

Original value: 228

New value: 750

Injector Open Time Compensation

The new Injectors have a different lag time (response time), so you'll need to change the setting using the Injector Open Time Compensation Maps found at.

  • Maps by Function → Fuelling → Port Injector scaling → Injector Opening Time Compensation

Set this map with the values shown below.

Low Pulse Width Injector Compensation

  • Maps by Function → Fuelling → Port Injector scaling → Low pulse Width Injector Compensation

Cranking Fuel Maps

The Cranking fuel maps will need reducing when larger injectors are fitted because the port injectors are used in the crank condition, and the EcuTek injectors have more than three times the flow of the original units.

When these injectors were fitted to our development vehicle we reduced the values by 75% in all of the cranking fuel maps shown in the screenshot below; you may have to reduce/increase these map values for your application or for running on ethanol fuels. Be sure to adjust all cranking maps by the same percentage.These maps are found i

  • Maps by Function → Fuelling → Cranking → Cranking Fueling #1 → #5b

Set these maps to 25% of their original value but selecting all of the values and pressing CTRL + P.

Cranking fuel is calculated by Manifold Absolute Pressure and if the MAP sensor has been changed you must ensure that the correct MAP sensor scaling has been entered.

You can simply verify the MAP sensor scaling by turning on the ignition and checking atmospheric pressure, which should be 1.0 bar at sea level with the engine NOT running.  MAP sensor accuracy is important for the cranking fuel volume to deliver an amount of fuel to the point that if a stock car has a 2.5 or 3.0 bar sensor fitted and the MAP sensor scaling is not recalibrated, the engine won't start

You can now program the ECU, start the engine and check the whole fuel injection system for fuel leaks.

Tuning Tips

Only the port injectors are fired during cranking; these operate at idle when the engine is cold. They work at lower RPM, but with the factory calibration they do not run through the mid-range on higher load (2400rpm-5200rpm) but come back in at high RPM.

The fine-tuning procedure should be followed; you'll find it in the PDF-format BRZ Tuning guide (at C:\EcuTek\ProECUHelp\BRZ-FT86). Following the MAF scaling section of the manual will enable you to fine-tune the injectors.You can find further advice on setting up the port and direct injection ee the ProECU BRZ Tuning guide for further advice on setting up the port and direct injection settings.

No other Warranties

To the maximum extent permitted by applicable law, EcuTek disclaim all other warranties and conditions, either express or implied, including, but not limited to, implied warranties or conditions of merchantability, fitness for a particular purpose, title and non-infringement, with regard to this product, and the provision of or failure to provide support services.

To the maximum extent permitted by applicable law, in no event shall EcuTek be liable for any special, incidental, indirect, or consequential damages whatsoever (including, without limitation, damages for loss of business profits, business interruption, loss of business information, or any other pecuniary loss) arising out of the use of or inability to use the product or the failure to provide support services, even if EcuTek has been advised of the possibility of such damages.

Contact Us:

EcuTek Technical Support

(+44) 1895 811200

When dialing from within the UK, the country code is not required so dial 01895 811200

Open Hours

Monday to Friday 9:00am - 5:00pm BST (UK Time)

(4am-1230pm Eastern Standard TIme US)

Visitors by appointment only

EcuTek Tehnologies Ltd.
8 Union Buildings
Wallingford Road
Uxbridge, UB8 2FR

VAT No: 
GB 235 2616 23