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M54 Engine Intake Manifold Replacement
 
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Pelican Technical Article:

M54 Engine Intake Manifold Replacement

Nick Czerula

Time:

4 hours4 hrs

Tab:

$250

Talent:

*****

Tools:

Set of sockets (8mm, 10mm, 13mm), wrenches, screwdrivers, fuel line socket

Applicable Models:

BMW X3 Sport Utility (2004-06)

Parts Required:

Intake manifold gaskets, hose clamps, fuel line hose clamps, fuel line O-rings, coolant hoses and pipes

Hot Tip:

Work with a cool engine

Performance Gain:

Repair vacuum leaks from old gaskets

Complementary Modification:

Replace crankcase vent valve or coolant hoses

On the 6-cylinder M54 engine installed in BMW X3 vehicles, the molded plastic intake manifold is configured as two sets of three runners with variable lengths. Low end torque and high end power are improved by varying the intake runner length according to a map stored in the ECM. Engine vacuum, load and ambient temperature are used by the ECM to determine the rpm at which to switch intake manifold configuration. The actuator used by the ECM to switch manifold configuration is a vacuum solenoid called the dual resonance intake system or DISA valve.

At low to mid-range engine speeds (up to about 3750 rpm), engine torque is increased as the DISA valve closes a flap inside the manifold, effectively increasing the length of the intake runners.

From mid-range to high engine speeds (4100 rpm and higher), DISA is de-energized. This opens the resonance flap inside the intake manifold and allows air to be drawn into cylinders through additional intake runners. This provides extra air for the power needed at higher rpms.

Another function of the design is that resonance waves inside the manifold pulse back and forth between opening and closing intake valves and help in cylinder filling.

If you have a hard-to-find vacuum leak, replace your intake manifold gaskets. If you find oil inside your intake manifold, replace the crankcase breather valve. Clean the inside of the intake manifold thoroughly and be careful not to get any debris inside the cylinder head during the procedure. Removing the intake manifold will also give you easy access to the engine starter, knock sensors or coolant pipes and hoses.

BMW E83 X3 models with an M54 6-cylinder engine utilize a runner profile style gasket for the intake manifold. Over time, the gaskets harden from heat or they swell from oil contamination.

It's a good idea to relieve the fuel system pressure before beginning. This will minimize the amount of fuel spilled. The best way to relieve fuel system pressure is to remove the fuel pump fuse and run the vehicle until the engine stalls. How to do this is described later in this procedure.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability.

Vehicle models change and evolve as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

Remove the engine covers and microfilter housing. See our tech articles on engine cover removing and cabin filter replacing.

Remove the DISA valve and throttle housing. See our tech articles for both procedures.

On the 6-cylinder M54 engine installed in BMW X3 vehicles, the molded plastic intake manifold (red arrow) is configured as two sets of three runners with variable lengths.
Figure 1

On the 6-cylinder M54 engine installed in BMW X3 vehicles, the molded plastic intake manifold (red arrow) is configured as two sets of three runners with variable lengths. Low end torque and high end power are improved by varying the intake runner length according to a map stored in the ECM. Engine vacuum, load and ambient temperature are used by the ECM to determine the rpm at which to switch intake manifold configuration. The actuator used by the ECM to switch manifold configuration is a vacuum solenoid called the dual resonance intake system or DISA valve.

Be prepared to catch leaking fuel when the fuel lines are disconnected.
Figure 2

Be prepared to catch leaking fuel when the fuel lines are disconnected. Disconnect the negative (-) battery cable. Working at the fuel rail, remove the fuel test port cap. Then place a rag over the Schrader valve and open the valve with a flathead screwdriver (red arrow) to relieve any remaining pressure.

Working near the left strut tower, reach beneath the intake manifold (rear corner).
Figure 3

Working near the left strut tower, reach beneath the intake manifold (rear corner). Follow the fuel line (red arrow) to the fuel rail connection until you locate the quick connect. To disconnect the fuel line, press and hold the release collar (blue arrow) while pulling the fuel line straight off. Have a rag handy to catch any dripping fuel. Follow the fuel line behind the intake manifold, near the firewall. You can see the line, but will have to do this part mostly by feel. Reach behind the intake manifold.

Working at the top of intake manifold, locate the oxygen sensor connectors.
Figure 4

Working at the top of intake manifold, locate the oxygen sensor connectors. Remove (red arrow) both square connectors out of the mounting bracket and lay them aside. Front connector shown, repeat for rear connector.

Then pull the other two oxygen sensor connectors (red arrow) out of the mounting brackets and lay the harness aside.
Figure 5

Then pull the other two oxygen sensor connectors (red arrow) out of the mounting brackets and lay the harness aside. Front connector shown, repeat for rear connector.

Pull the oxygen sensor harnesses out of the mounting clip at the rear of the intake manifold.
Figure 6

Pull the oxygen sensor harnesses out of the mounting clip at the rear of the intake manifold. Then locate the wire tie (red arrow) and cut it. Be sure to install a new wire tie when reinstalling the fuel injectors.

Working at the front left corner of the valve cover, disconnect the breather hose (blue arrow) by squeezing the collar and pulling it straight off.
Figure 7

Working at the front left corner of the valve cover, disconnect the breather hose (blue arrow) by squeezing the collar and pulling it straight off. Then disconnect the VANOS solenoid electrical connector (red arrow) be pressing the wire release and pulling it straight off the solenoid.

Working at the front of the intake manifold, squeeze the crankcase vent hose (red arrows) release tabs and pull them off the intake manifold.
Figure 8

Working at the front of the intake manifold, squeeze the crankcase vent hose (red arrows) release tabs and pull them off the intake manifold. Then, rotate the hose toward the wiper cowl to move it out of the way.

Then release the fuel injector harness strip from the fuel injectors and remove it.
Figure 9

Then release the fuel injector harness strip from the fuel injectors and remove it. I find the easiest way to do this is to use a large flathead screwdriver and gently pry up (red arrow) at each fuel injector. This will release the spring clips that hold the electrical harness to the fuel injectors. If stuck, try a swift prying action to detach the connector. Work your way down the injectors lifting the harness housing (blue arrow) while disconnecting the injector harness. Lay the fuel injector harness aside.

Working at the right strut tower, open the jump start terminal cover.
Figure 10

Working at the right strut tower, open the jump start terminal cover. Then loosen and remove the 19mm nut, then remove the cable from the junction.

Working at the rear left of the intake manifold, remove the 10mm plastic nut (red arrow).
Figure 11

Working at the rear left of the intake manifold, remove the 10mm plastic nut (red arrow). Remove the cable and plastic holder from the stud.

Working at the brake booster, remove the brake booster vacuum hose (red arrow) by pulling it straight out of the brake booster.
Figure 12

Working at the brake booster, remove the brake booster vacuum hose (red arrow) by pulling it straight out of the brake booster. Check that the rubber grommet is in good shape when reinstalling. If needed, replace it.

Working the left lower corner of the intake manifold (red arrow), unclip the wiring harness and any hoses that are hooked to the corner of the manifold.
Figure 13

Working the left lower corner of the intake manifold (red arrow), unclip the wiring harness and any hoses that are hooked to the corner of the manifold. Note locations for reinstallation.

Working below the intake near the throttle housing mounting surface (red arrows), locate the intake manifold mounting bracket.
Figure 14

Working below the intake near the throttle housing mounting surface (red arrows), locate the intake manifold mounting bracket. Then remove the 16mm nut from the mounting bracket (red arrows).

Working at the front of the intake manifold, pull the evaporative emission purge solenoid off the mounting bracket.
Figure 15

Working at the front of the intake manifold, pull the evaporative emission purge solenoid off the mounting bracket. It is mounted in a rubber bushing and pulls straight off the bracket. Disconnect the electrical connector by squeezing the release tab and pulling it off. Then detach the lower hose by squeezing the collar and pulling it straight off (red arrow).

Remove the nine 11mm intake manifold nuts (red arrows).
Figure 16

Remove the nine 11mm intake manifold nuts (red arrows). Once the fasteners have been removed, lift the intake manifold up and off the cylinder head. The fuel rail has been removed for clarity, you do have to remove it to access the intake nuts.

Continue to lift the intake manifold off the cylinder head, disconnecting hoses or electrical connectors.
Figure 17

Continue to lift the intake manifold off the cylinder head, disconnecting hoses or electrical connectors.

If removing the manifold completely, feed the battery cable (red arrow) through the intake runners, note the position and orientation of the cable.
Figure 18

If removing the manifold completely, feed the battery cable (red arrow) through the intake runners, note the position and orientation of the cable. If just replacing the seals on the intake, leave the cable in place, flip the intake over to access the seals. Then remove the intake manifold from the engine.

Once removed, seal the intake ports (red arrows) to prevent debris from entering the cylinder head.
Figure 19

Once removed, seal the intake ports (red arrows) to prevent debris from entering the cylinder head.

Before installing, replace the intake manifold gaskets.
Figure 20

Before installing, replace the intake manifold gaskets. Remove by prying the gaskets out with a small flathead screwdriver. Install the new gaskets by pressing in. Check that all gaskets are properly seated before installing the intake manifold. If you plan to replace your crankcase breather valve now is a good time. You have great access to it, and you can easily connect the hoses. See our tech article on crankshaft breather valve replacing. Remove items you used to seal the intake ports on the cylinder head. Then install the intake manifold to the cylinder head and tighten the fasteners in an alternating pattern. Reconnect the electrical connectors then reconnect the fuel lines. Reinstall the evaporative emission purge valve. Reconnect the fuel injectors and oxygen sensors. Reinstall the remaining items in the reverse order of removal. Double check the wiring harness routing and fuel line connections. Once complete, let the engine idle for about 10 minutes. If you left something disconnected or an item is misrouted, it is best to find out before driving. Check and clear any fault codes.

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Page last updated: Wed 3/22/2017 03:11:34 AM