01-31-2012, 12:59 PM
Join Date: Sep 2009
My Ride: 330 Ci convertible
Project M54 Engine: Fuel Injection Rail
Fuel Injection Rail
Links to other parts of the project
Removal of the fuel injection rail is required need to change an injector, or if you want to remove the intake manifold.
Before I start, I looked at the methods described in the Bentley manual, and other DIYs that have been posted in different places. I used them all, and found most quite difficult. I tried a whole bunch of things over and over and eventually came up with this method. The problem with the fuel rail is there are a number of things layered here, and if attempted in the wrong order, or in the wrong way, it is easy to break things. You will notice that the oil separator pipe at the top of the intake manifold in the photos is covered in tape. This is because it was broken when I attempted to do it as per another DIY.
The way I will show you I think is much easier, and much less likely to break something.
Also, most methods talk about releasing the fuel pressure from the fuel rail before you start. If you are actually going to remove the injectors from the rail then this is obviously required. If you plan to just remove the intake manifold, then I would not release the pressure.
If you want to remove the pressure and fuel from the rail, this is the way I would do it.
1. Remove the fuel pump fuse.
2. Start the car and wait until is starts to run rough. Then turn it off.
3. Disconnect the battery.
4. Put a rag over the shraeder valve on the front of the rail, and then press down on the pin to release the remaining pressure in the rail. (the shraeder valve is the name given to the valve that you use to pump up your tyres. The one on the fuel rail is exactly the same.)
5. Connect a hand bicycle pump to the shraeder valve at the front of the rail and give a good number of pumps to try and remove as much of the fuel out of the rail as possible.
Finally, I have no idea what the funny plastic thing that sits on top of the intake manifold that receives the air from the oil separator. I have called it the "oil separator part of the intake manifold" or OSIM.
The methods I have seen published elsewhere did not have you disconnect the OSIM, they said to just disconnect the oil separator pipe from the two connectors below it. This is difficult. There's no space to get your fingers in, and you need to use some long nose pliers. The connectors are really stuck on, and when the eventually release (with you pulling as hard as you can) things break easily. This is why I think it is better to lift off the OSIM, with the pipe coming with it and out of the way.
Once the oil separator pipe is out of the way, you can remove the injector harness. The first photo here has the injector removed so you can see easily what you need to do. Use a small pick tool to get under the clips and remove them. This is the biggest pain of the whole job. Make sure you have a magnetic pickup tool touching the clip as you try and remove them, they can spring all over the place.
Once all clips have been removed from each injector connector, you can easily pull off the harness. Intake cam sensor and intake air temp sensor connectors will also need to be disconnected. Place the whole harness out of the way.
Now remove the small bolts that hold on the rail.
And gently pry up the fuel rail. Don't just pull it up by hand. You will need to use a lot of force, and when it gives, it will happen very quickly. Easy to break something expensive. If you do it as shown it is dead easy.
When all the injectors are out, you can lift and rotate the whole rail with injectors still attached as shown.
There is a flexible fuel hose at the back of the engine that connects to the fuel rail. This hose is held in place by a clip at the back of the intake manifold. Release this by getting your hand down the back under the manifold and unclip it.
If you want to remove the fuel rail completely now is the time to do it. You will need to have removed the fuel pressure from the fuel rail as described at the top. Then you can disconnect the flexible hose from the fuel rail. The photos show the hose still attached at the clip, but this would be much easier to do when the hose is removed from the clip.
If you do need to remove an injector, this is how you do it. Again, you will need to have removed the fuel pressure from the rail to do this.
There you have it.
Reassembly is the opposite, but is much simpler. Tips I have are:
1. Connect the injectors to the rail before putting the injectors in the intake manifold.
2. Push in the injectors and rail by hand into the intake manifold before putting in screws. Don't try and screw them down to seat them. It won't work. To help get the injectors into place, I smeared the smallest amount of engine oil around the O Ring that goes into the intake manifold, and they slid in easily.
3. Have the injector harness clips placed back into their correct position before attaching the harness. The harness connectors will slide on and clip in easily.
3. Same procedure for the OSIM as for seating the injectors.
I couldn't find any torque figures for reinstallation on either BMW TIM or the Bentley manual. Just make sure they are well attached but not over tightened.
Last edited by jjrichar; 02-14-2012 at 12:54 PM.
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