Detailed Disassembly Procedure - Page 1


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On this page we'll attend to all the items which need to be disassembled to allow removal of the intake manifold and valley pan. 

 

Most of the required parts... note that I didn't realize the heat shield would be so brittle, so didn't have one on hand prior to beginning work.

Disconnect battery positive lead.

- make sure your seats/mirrors are in their #1 saved position so you can return them after reapplication of power.

Remove engine cover.

- Note that I realized three of the four foam donuts that sit on the cover’s mounting pegs were gone - I later found them sitting down on the intake manifold.

 

Remove Idle Control Valve if so equipped

- disconnect wire harness from valve (A)

- disconnect plumbing (at both ends) running between valve and intake flex hose, move aside for now (B)

- carefully disengage (don’t break off mounting feet) rubber hose clamp surrounding valve from bracket (C)

- rotate valve upward to disconnect from throttle body, set valve aside.

 

Disconnect and remove flex line between MAF and ASC throttle body.

- release hose clamps on both ends (A)

- reach underneath and disconnect flex hose from intake resonator box by supporting resonator while steadily pulling up on underside of hose (B)

 

Engine Cover Supports

- Carefully disconnect red snap fitting at throttle cables (it will probably break)

- remove four 10mm bolts, two on each support (A). Don’t drop bolts. Set supports aside

 

Fuel Lines

- remove fuel lines at driver’s side rear of engine block (four places). Grasp hose portion and push toward connector. Using other hand, press black lock ring toward hose, then release hose from pipe. CAUTION: fuel may be under significant pressure.

- Using a baggie and zip tie on EACH of four fuel pipes, seal off pipes (two on intake manifold and two on fender well). Place removed hoses in a clean environment - ie., inside a large ziplock bag.

 

 

Driver’s side electrical harness

- remove valve cover plate (A) - carefully pry up two small plastic covers to gain access to mtg bolts. Remove 10mm bolts. Pry plate away from valve cover with hands. Remove and set aside.

- disconnect coils (B). On each of four coils, lift silver-gold connector lock clip, then disconnect harness connector from coil.

- disconnect circular knock sensor harness (C) (there may be two such connectors on VANOS motors. Also on VANOS motors I think there is a second cam position sensor harness).

- remove two 10mm nuts (D) attaching harness covering (black plastic rectangular box) to head. Set nuts aside.

- disconnect electronic harness from rear-most injector (E) - working from bottom of connector, press metal retaining clip upward to release.

- disconnect harness cover from fuel injectors. The driver’s side cover is essentially one large connector, providing electrical connection to the front three injectors on this side. Grasp the cover/box with both hands and pull directly up and away from the injectors (straight away from the injectors, a 45 degree angle from the vertical) - try to disconnect the cover from all three injectors at the same time. Be prepared for the release: stop pulling as soon as the cover comes free. Allow cover to simply lay on head at this point.

 

Accelerator Cables

- move main throttle lever backward with one hand while disconnecting both accelerator and cruise control cable ends from lever - the plastic retainers unsnap forward (A).

- remove throttle cable bracket from front of throttle body - 2x T30 Torx bolts (B). This way you don’t need to readjust the cable position when you’re done.

- move ASC throttle lever (C) (on underside of secondary throttle body) backward (clockwise looking down) to create slack in the ASC cable. Remove the cable from the lever by unsnapping barrel end from lever and threading cable thru slot. Pull ASC cable from mounting lug (D) on lower-right side of secondary throttle body. You do not need to remove any more of the ASC cable.

Passenger side electrical harness

- remove valve cover plate (A) (the BMW plate) - same as driver’s side.

- disconnect coils - same as driver’s side.

- disconnect circular knock sensor harness (B) and crankshaft position sensor harness (C) - lay each harness out of way toward front of motor.

- remove two 10mm nuts (D) attaching harness cover head. Set nuts aside.

- disconnect harness cover from fuel injectors. The passenger side cover is the same as the driver’s side except that it connects to all four injectors. Allow cover to simply lay on head at this point.

- disconnect electrical connector from fuel tank breather valve (E) (driver’s side front of engine block)

- disconnect electrical connector from main and secondary throttle position sensors (F).

 

Vacuum Control Plumbing

- locate black pipe that runs front/back along upper driver’s side of intake manifold. Remove single 10mm bolt (A) holding bracket at front-center of intake manifold (note: rear bracket should already be loose when driver’s harness cover was removed).

- follow black pipe rearward - it connects to a rubber hose, which in turn runs into a ‘T’ connector (B). The hose that runs from this ‘T’ over to the rear of the intake manifold must be disconnected at the manifold (C). This is a large press-fit ‘L’ connector which runs into a rubber grommet in the rear face of the manifold. Carefully work the ‘L’ fitting loose from the grommet, twisting and pulling it rearward from the manifold.

- Return to the black pipe where it connects to a rubber hose - cut and remove the factory crimp connector (D) (don’t damage the hose) and disconnect the black vacuum pipe from the hose. At this point the intake manifold vacuum plumbing is disconnected from the car. During reassembly you will replace this crimp connector with a screw-type hose clamp. Allow the black pipe to rest on the intake manifold.

 

 

Engine Vent Tube

- PITA Alert! The vent tube is located under the intake manifold (dotted lines in photo), runs along the driver’s side head/block, and connects the block to the intake manifold. This tube must be disconnected from the intake manifold prior to the manifold’s removal.

- Remove the driver’s side air duct between the cabin air filter box and firewall - at the filter box, release the retainer strap, then rotate the duct 45 degrees counterclockwise and pull forward away from the firewall. Set duct aside.

- The vent tube mounts to the intake manifold (A) via an o-ring sealed slip fit. The tube is retained by a spring clip (B), which snaps around the tube (C) and clips over the manifold’s fitting (A). This clip is accessed at the driver’s side rear of the intake manifold, down low. Using a small screwdriver, gently pry this clip up away from the tube. If the clip slides forward on the tube under the manifold, don’t worry - you’ll retrieve it later. If it falls off down into the motor, get it now before you forget.

- Now slide the vent tube (C) forward off the connector fitting - it will probably be stuck, so judicious use of a large screwdriver to help pry it away may be called for. Work slowly and don’t break anything. Slide the tube all the way forward until you see that it is completely disconnected from the fitting.

 

 

 

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