Fuel Injector Replacement – BMW N20 Turbo 4 Cylinder Engine
Step 1 - Purchase Parts
Fuel Injector
Direct injection fuel injectors are notoriously expensive. Many home mechanics try and save money by installing "imported" aftermarket injectors often found on sites like Amazon and Ebay. Big mistake. Please take our word on this...you get what you pay for with fuel injectors. Cheap aftermarket versions will fail and can even possibly cause major damage to your engine. Don't cut corners - even if you have to take out a loan, only install Genuine BMW fuel injectors like this one in your vehicle.
Fuel Injector Removal Tool
When it comes to BMW specific tools, we cannot stress enough staying away from cheap reproductions. This is the actual BMW fuel injector extraction tool used at the dealership - unlike the cheaper aftermarket versions it fits and operated flawlessly. Never try to remove or install a direct injection fuel injector without the proper tool...you can cause catastrophic damage to the engine head.
Professional Diagnostic Scan Tool for BMW/MINI
Affordable and powerful...this is the only BMW diagnostic scanner you will ever need. Schwaben Multi-System Elite Scanner is a unique tool that delivers dealership level diagnosis for BMW and MINI vehicles. Works on 1987-current model BMW and MINI models. Display fault codes, clear error lights, reset Conditional Based Service (CBS) settings, register new batteries, calibrate fuel injectors, reset adaptations and more. Displays live data for entire vehicle allowing high level diagnostics and repairs. Extremely easy to use, this is the
Step 2 - Repair Procedure
You must disconnect the negative battery cable before starting this repair. Not disconnecting the battery could cause catastrophic damage to the engine electronics.
You must remove the ignition coils before starting this repair.
Please see our article Ignition Coil Replacement – BMW N20 Turbo 4-Cylinder Engine for instructions on removing the ignition coils.
- Remove the bolts (2) anchoring the high pressure fuel line to the engine. Remove the cable clip (3).
- Loosen the two union nuts (1), then unclip the high pressure fuel line and remove from the engine compartment.
- Loosen the two four union nuts (2). Unscrew the fuel rail anchor bolts (3) a few turns until the fuel rail (4) is loose.
- Rotate the fuel rail to the left until the injectors can be safely removed.
- Unplug the electrical connector from the fuel injectors (1). Remove the ground cable nut (2) and fold the wire back out of the work area.
- Remove nut (1) and bolt (2) securing the injector bracket (3) to the engine head. Remove the bracket from the engine compartment.
- In order to remove th fuel injectors, you must use the special BMW tool 83300496885. Please see our required tool block above for more information.
- Before using the tool, lightly grease the extraction threads (1) to keep the tool from binding up while pulling the fuel injectors out of the head.
- Position the fuel injector removal tool (1) on the engine head as shown in the image.
- Screw in the tools mounting bolts (2) a few turns to keep the tool from moving. Do not tighten yet.
- Turn the extraction threads (4) far enough down that the threaded sleeves (3) can be threaded onto the top of the fuel injectors.
- Screw the threaded sleeves (3) onto the top of the injectors and tighten the tools mounting bolts (2).
- Using a torque wrench set to 5 Nm (3.6 ft-lb) and a crows foot socket, turn the extraction thread clockwise (3) slowly until the fuel injector is pulled from the cylinder head.
- Repeat for the second injector.
Read calibration value before installing!
- Each new fuel injector has a calibration value stamped on its shaft. You MUST document this number and which injector it is associated with before installation. This number will be used to calibrate the new fuel injectors in later steps.
- Read and document the calibration adjustment value and the cylinder location for each new fuel injector as shown in the image.
- If there is no calibration number on the shaft of the fuel injector, use the default value of 2.15!
- Install the new fuel injectors with the extraction tool following the above steps in reverse EXCEPT the torque wrench should be turned counterclockwise and set to 2 Nm (1.5 ft-lb) while tightening the extraction thread (3).
Important torque values:
Injector bracket to cylinder head bolts - 13 Nm (9.5 ft-lb).
Fuel rail to cylinder head - 7 Nm (5 ft-lb).
High pressure fuel lines to top of injectors - 23 Nm (17 ft-lb).
High pressure fuel lines to fuel rail - 30 Nm (22 ft-lb).
- Using a diagnostic scanner (see our special tools block above to purchase one), calibrate the four new fuel injectors using the adjustment values recorded in the above step.