74 BMWcar
WORKSHOP WISDOM
There are a couple of pressure/temp sensors down
at the back. There’s one on the manifold and it’s the
pressure sensor to be disconnected. The other is on
the fuel rail sensor. I’ve shown the manifold pressure
sensor with the manifold removed for clarity.Next, the rear engine acoustic cover can be taken
off. These covers are typically a bit of a struggle to
remove (and refit), but it’s pretty easy in this case,
with the rear covers and cross bars removed – it’s
much harder on the E46. There are 5mm Allen screws
and you should take care not to mix them up.The injector loom is unplugged, the two small Torx
screws are removed and then the loom is free. Pull
it back, tuck it to one side to keep it out of harm’s
way. It’s designed in such a way that it cannot be
reassembled incorrectly.Here’s the EGR valve pipe being disconnected. Use a
flat-blade screwdriver to undo the Jubilee clip. Undo
it all the way so that the clip comes off as well as the
two-piece metal clasp that clamps the pipe to the
side of the EGR intake.Disconnect the battery earth cable. You will be under the bonnet in a minute and disconnecting the power cable
to the engine – it would be all too easy to short it out with a 13mm spanner! Under the bonnet, remove the plastic
cap and disconnect the power cable to the positive power stud. It’s the cable going across the top of the engine.Now use a flat-bladed screwdriver to separate the
brake vacuum pipe from the connector – these are
tricky. There’s a 10mm bolt that secures the dipstick
tube to the manifold. It’s not too bad to remove, but
is trickier to refit and I’d happily bet that a few get
‘accidentally’ left off!The intake boost pipe from the EGR intake is
disconnected by pulling up the metal clip on the
intake pipe with a small screwdriver, and wiggling
it off. These later-type boost pipes are much better
than the old rubber ones used on the E46.The centre Torx bolt is a T25 that you access by
removing the plastic cover disc. Take care to remove
this without damaging it, using a two-pence coin.
It won’t be tight, and only needs to be rotated by a
quarter-turn to release it. This will reveal the T25 bolt
that’s tightened to 60Nm.(^45)
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