Time – 3 hours
Cost – Full set of Fuel Injectors, reconditioned, ultrasonically cleaned and matched flow rate £58
Source - Bavarian Werke Fuel Injector Store – E-Bay
Difficulty Rating -
***Important Read Before You Start***
- Spanners 10mm, 11mm, 13mm
- Flat Bladed Screw Driver
You are completing a job that requires venting of the fuel system, please ensure that you take the necessary precautions:
I am not responsible for your safety, so please assess the risks of doing this job yourself before starting, and get a mechanic to complete for you if you do not feel competent to carry this procedure out.
- Work in a well ventilated area
- Be prepared to catch and control any spills
- Have a fire extinguisher available at point of use
The Strip Down Process
Open the bonnet (hood for our American friends)
Unplug the MAF and remove the Air Temp Sensor
Undo the throttle body gaiter band clip and remove the vacuum hose
Unclip both throttle body sensor plugs
Remove both vacuum hoses from the throttle body
Undo the band clip on the top vacuum hose on the plenum chamber and remove the hose
Undo the plenum chamber centre bolt and two side nuts
Undo the front and back plenum-retaining bracket bolts do not remove fully
Remove the top plenum chamber and place to on side
Remove the rocker cover breather pipe
Remove the fuel rail bleed nipple cap
Now you have access to remove the pressure from the fuel rail, ensure that you put some rags or cloth around the area as you will release fuel when doing this next step.
Using a suitable tool (star screw driver) depress the bleed nipple (similar to loosing air out of your tyre) until no more fuel runs out.
Ensure you mop / dry up any fuel.
Undo both fuel supply lines and then unscrew the fuel rail, be careful the fuel rail contains fuel, but it is not under pressure, if you followed the previous step, ensure you capture any spillage.
The fuel rail together with the Injectors should now pull free, disconnect the electrical connectors (careful not to lose the spring clips)
You can see how dirty the Injectors are and how the o’rings have shrunk over time to allow dirt and oil in and around the Injector
With the fuel rail assembly on the bench you can now unclip the injectors by removing the metal clip with a flat blade screwdriver and pull the injectors free and remove the vacuum hoses
Fitting the new injectors is a reversal of the removal, push the injector home and slide in the clip, attach the vacuum hoses
When refitting the fuel rail system back into the engine, line the injectors up with the relevant port, and attach both fuel lines first, and then the two fuel rail bolts, the tightening of the bolts will pull the injectors home into their ports (no excessive force required)
Rebuild is a reversal of the strip down procedure – Job done!
M44B19 Fuel Injector Replacement
This article details the procedure to replace the BMW Z3 M44B19 Fuel Injectors. This is a procedure which can be carried out by a competent home mechanic, but as you are dealing with the fuel system, extreme care should be taken.